Learn how to install SSH to a Docker container and how to SSH to other Docker containers.

Blocking APIs can hurt your applications performance. So does using Asynchronous EJBs help?

Read about the state of DevOps, including Puppet Labs' 2015 report, cloud computing, and Apple Watches.

In this article, excerpted from the book Docker in Action, I will show you how to open access to shared memory between containers. Linux provides a few tools for sharing memory between processes running on the same computer. This form of inter-process communication (IPC) performs at memory speeds. It is often used when the latency associated with network or pipe based IPC drags software performance below requirements. The best examples of shared memory based IPC usage is in scientific computing and some popular database technologies like PostgreSQL. Docker creates a unique IPC namespace for each container by default. The Linux IPC namespace partitions shared memory primitives like named shared memory blocks and semaphores, as well as message queues. It is okay if you are not sure what these are. Just know that they are tools used by Linux programs to coordinate processing. The IPC namespace prevents processes in one container from accessing the memory on the host or in other containers. Sharing IPC Primitives Between Containers I’ve created an image named allingeek/ch6_ipc that contains both a producer and consumer. They communicate using shared memory. Listing 1 will help you understand the problem with running these in separate containers. Listing 1: Launch a Communicating Pair of Programs # start a producer docker -d -u nobody --name ch6_ipc_producer \ allingeek/ch6_ipc -producer # start the consumer docker -d -u nobody --name ch6_ipc_consumer \ allingeek/ch6_ipc -consumer Listing 1 starts two containers. The first creates a message queue and starts broadcasting messages on it. The second should pull from the message queue and write the messages to the logs. You can see what each is doing by using the following commands to inspect the logs of each: docker logs ch6_ipc_producer docker logs ch6_ipc_consumer If you executed the commands in Listing 1 something should be wrong. The consumer never sees any messages on the queue. Each process used the same key to identify the shared memory resource but they referred to different memory. The reason is that each container has its own shared memory namespace. If you need to run programs that communicate with shared memory in different containers, then you will need to join their IPC namespaces with the --ipc flag. The --ipc flag has a container mode that will create a new container in the same IPC namespace as another target container. Listing 2: Joining Shared Memory Namespaces # remove the original consumer docker rm -v ch6_ipc_consumer # start a new consumer with a joined IPC namespace docker -d --name ch6_ipc_consumer \ --ipc container:ch6_ipc_producer \ allingeek/ch6_ipc -consumer Listing 2 rebuilds the consumer container and reuses the IPC namespace of the ch6_ipc_producer container. This time the consumer should be able to access the same memory location where the server is writing. You can see this working by using the following commands to inspect the logs of each: docker logs ch6_ipc_producer docker logs ch6_ipc_consumer Remember to cleanup your running containers before moving on: # remember: the v option will clean up volumes, # the f option will kill the container if it is running, # and the rm command takes a list of containers docker rm -vf ch6_ipc_producer ch6_ipc_consumer There are obvious security implications to reusing the shared memory namespaces of containers. But this option is available if you need it. Sharing memory between containers is safer alternative to sharing memory with the host.

[This article was written by Sveta Smirnova] Like any good, thus lazy, engineer I don’t like to start things manually. Creating directories, configuration files, specify paths, ports via command line is too boring. I wrote already how I survive in case when I need to start MySQL server (here). There is also the MySQL Sandbox which can be used for the same purpose. But what to do if you want to start Percona XtraDB Cluster this way? Fortunately we, at Percona, have engineers who created automation solution for starting PXC. This solution uses Docker. To explore it you need: Clone the pxc-docker repository:git clone https://github.com/percona/pxc-docker Install Docker Compose as described here cd pxc-docker/docker-bld Follow instructions from the README file: a) ./docker-gen.sh 5.6 (docker-gen.sh takes a PXC branch as argument, 5.6 is default, and it looks for it on github.com/percona/percona-xtradb-cluster) b) Optional: docker-compose build (if you see it is not updating with changes). c) docker-compose scale bootstrap=1 members=2 for a 3 node cluster Check which ports assigned to containers: $docker port dockerbld_bootstrap_1 3306 0.0.0.0:32768 $docker port dockerbld_members_1 4567 0.0.0.0:32772 $docker port dockerbld_members_2 4568 0.0.0.0:32776 Now you can connect to MySQL clients as usual: $mysql -h 0.0.0.0 -P 32768 -uroot Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 10 Server version: 5.6.21-70.1 MySQL Community Server (GPL), wsrep_25.8.rXXXX Copyright (c) 2009-2015 Percona LLC and/or its affiliates Copyright (c) 2000, 2015, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. mysql> 6. To change MySQL options either pass it as a mount at runtime with something like volume: /tmp/my.cnf:/etc/my.cnf in docker-compose.yml or connect to container’s bash (docker exec -i -t container_name /bin/bash), then change my.cnf and run docker restart container_name Notes. If you don’t want to build use ready-to-use images If you don’t want to run Docker Compose as root user add yourself to docker group

written by tim brock. scatter plots are a wonderful way of showing ( apparent ) relationships in bivariate data. patterns and clusters that you wouldn't see in a huge block of data in a table can become instantly visible on a page or screen. with all the hype around big data in recent years it's easy to assume that having more data is always an advantage. but as we add more and more data points to a scatter plot we can start to lose these patterns and clusters. this problem, a result of overplotting, is demonstrated in the animation below. the data in the animation above is randomly generated from a pair of simple bivariate distributions. the distinction between the two distributions becomes less and less clear as we add more and more data. so what can we do about overplotting? one simple option is to make the data points smaller. (note this is a poor "solution" if many data points share exactly the same values.) we can also make them semi-transparent. and we can combine these two options: these refinements certainly help when we have ten thousand data points. however, by the time we've reached a million points the two distributions have seemingly merged in to one again. making points smaller and more transparent might help things; nevertheless, at some point we may have to consider a change of visualization. we'll get on to that later. but first let's try to supplement our visualization with some extra information. specifically let's visualize the marginal distributions . we have several options. there's far too much data for a rug plot , but we can bin the data and show histograms . or we can use a smoother option - a kernel density plot . finally, we could use the empirical cumulative distribution . this last option avoids any binning or smoothing but the results are probably less intuitive. i'll go with the kernel density option here, but you might prefer a histogram. the animated gif below is the same as the gif above but with the smoothed marginal distributions added. i've left scales off to avoid clutter and because we're only really interested in rough judgements of relative height. adding marginal distributions, particularly the distribution of variable 2, helps clarify that two different distributions are present in the bivariate data. the twin-peaked nature of variable 2 is evident whether there are a thousand data points or a million. the relative sizes of the two components is also clear. by contrast, the marginal distribution of variable 1 only has a single peak, despite coming from two distinct distributions. this should make it clear that adding marginal distributions is by no means a universal solution to overplotting in scatter plots. to reinforce this point, the animation below shows a completely different set of (generated) data points in a scatter plot with marginal distributions. the data again comes from a random sample of two different 2d distributions, but both marginal distributions of the complete dataset fail to highlight this separation. as previously, when the number of data points is large the distinction between the two clusters can't be seen from the scatter plot either. returning to point size and opacity, what do we get if we make the data points very small and almost completely transparent? we can now clearly distinguish two clusters in each dataset. it's difficult to make out any fine detail though. since we've lost that fine detail anyway, it seems apt to question whether we really want to draw a million data points. it can be tediously slow and impossible in certain contexts. 2d histograms are an alternative. by binning data we can reduce the number of points to plot and, if we pick an appropriate color scale, pick out some of the features that were lost in the clutter of the scatter plot. after some experimenting i picked a color scale that ran from black through green to white at the high end. note, this is (almost) the reverse of the effect created by overplotting in the scatter plots above. in both 2d histograms we can clearly see the two different clusters representing the two distributions from which the data is drawn. in the first case we can also see that there are more counts from the upper-left cluster than the bottom-right cluster, a detail that is lost in the scatter plot with a million data points (but more obvious from the marginal distributions). conversely, in the case of the second dataset we can see that the "heights" of the two clusters are roughly comparable. 3d charts are overused, but here (see below) i think they actually work quite well in terms of providing a broad picture of where the data is and isn't concentrated. feature occlusion is a problem with 3d charts so if you're going to go down this route when exploring your own data i highly recommend using software that allows for user interaction through rotation and zooming. in summary, scatter plots are a simple and often effective way of visualizing bivariate data. if, however, your chart suffers from overplotting, try reducing point size and opacity. failing that, a 2d histogram or even a 3d surface plot may be helpful. in the latter case be wary of occlusion.

16 Apr 2015 In a year defined by international expansion and investments in new infrastructure to enhance operational efficiency, Gulftainer recorded robust growth across its entire terminal portfolio. Iain Rawlinson, Group Commercial Director of Gulftainer said: “The positive growth recorded by Gulftainer across its terminals globally underlines the confidence of our partners in our ability to meet their requirements efficiently. Our extensive network and technological expertise are the strengths that have enabled us to expand our footprint to new locations. We continuously invest in enhancing our infrastructure, thus boosting reliability, operational efficiency and productivity.” He added: “The growth in volume achieved throughout our terminals is strong testament to the expertise and dedication of our employees and the strong productivity levels we are able to achieve on a consistent basis. In the dynamic global trade routes linking Asia and Europe, our terminals today play an increasingly significant role. Even as we expand and grow our business, we also remain committed to the communities we serve in by creating new jobs and supporting the domestic economy.” In global markets, Gulftainer’s Saudi terminals recorded impressive growth with Northern Container Terminal accounting for 1.9 million TEUs, sustaining previous-year trends, while Jubail Container Terminal (JCT) noted a growth of 22 per cent to over 396,000 TEUs. The total volume at the Saudi terminals was over 2.29 million TEUs. Gulftainer’s Umm Qasr terminal also accomplished a significant growth of 46 per cent in 2014, while the Recife terminal in Brazil marked a growth in volume of 7 per cent. Gulftainer’s UAE terminals recorded a total volume of 3.8 million TEUs in line with the all-round growth in business. The company marked another significant milestone, with the Sharjah Container Terminal (SCT) surpassing 400,000 TEUs in annual throughput for the very first time. Operations at SCT were energised by the positive growth in global trade and the arrival of new services, such as UASC’s Gulf India Service (GIS1), which now connects Sharjah with Sohar in Oman, Mundra in India and Karachi in Pakistan. The addition of this service represented a significant development for Sharjah and boosted the national carrier’s volumes through SCT last year. The only fully fledged operational container terminal in the UAE located outside the Strait of Hormuz, Khorfakkan Container Terminal (KCT) has today emerged as one of the most important transshipment hubs for the Arabian Gulf, the Indian Sub-continent, the Gulf of Oman and the East African markets. Further strengthening the operations at KCT, Gulftainer has received and commissioned new state-of-the-art Ship to Shore (STS) and Rubber Tyred Gantry (RTG) cranes that will further increase overall performance and productivity. This enhanced infrastructure marks an investment of over US$60 million. Gulftainer has set an ambitious target to triple the volume over the next decade through organic growth across existing businesses, exploring green field opportunities and potential M&A activities.

Gulftainer, a privately owned, independent terminal operating and logistics company, marked another significant milestone with the Sharjah Container Terminal (SCT) surpassing 400,000 TEUs (Twenty Foot Equivalent Units) in annual throughput during 2014. SCT has again recorded double-digit growth compared to last year’s volumes. The achievement was reached with an impressive safety record under challenging conditions including space constraints. Iain Rawlinson, Group Commercial Director of Gulftainer said that the professional approach of Gulftainer’s management, along with consistently high productivity levels, was a driving force behind the Terminal’s success. “SCT has always marketed itself as ‘The Flexible Alternative’ and the individual attention we extend to our customers offers us an advantage over competitors.” The 400,000th unit was discharged from Mag Container Lines’ vessel, ‘Mag Success’, one of the Terminal’s regular callers, which considers Sharjah as her base port. Speaking on behalf of Mag Line’s CEO, BDM Jamal Saleh congratulated the Terminal for its achievement. He said: “The announcement today reflects how Gulftainer and MCL have grown together over the years and, in partnership, managed to reach this target. The continuous support, flexibility and excellent operational performance MCL receives from Gulftainer, both operationally and logistically, has contributed greatly to this achievement.” The milestone was achieved on the shift of Duty Superintendent Mehmood Malik, the longest serving employee at over 38 years at the Terminal and part of the team when the first TEU crossed the quay. Mehmood has witnessed several records and milestones and recalls handling 2,500 TEUs in 1976: “At that time we could not imagine reaching the levels of throughput we have today, so this is a very special moment for me.” SCT, which is managed and operated by Gulftainer on behalf of the Sharjah Port Authority, has the honour of being the site of the first container terminal in the Gulf, commenced operations in 1976. SCT is located in the heart of Sharjah and is an ideal gateway for import and export cargo with direct links throughout the Gulf, Asia, Europe, Americas and Africa. The strong performance of the Sharjah economy has supported the growth of many of SCT’s customers, enabling them to increase their throughput and contribute to a record year for the Terminal. The relationships built with our customers have been strengthened by the joint efforts of Gulftainer’s sales and marketing team and the high levels of service and operational efficiency at the terminal, “When looking at the Sharjah market, the dedicated team at SCT listen to and address the many requirements of our diverse and interesting customer base,” said Iain Rawlinson. SCT’s figures have been further boosted with the arrival of new services throughout the year, including UASC’s Gulf India Service (GIS1), which now connects Sharjah with Sohar in Oman, Mundra in India and Karachi in Pakistan, which has boosted in the national carrier’s volumes through SCT in November and December. Gulftainer’s current portfolio covers UAE operations in Khorfakkan Port and Port Khalid in Sharjah as well as activities at Umm Qasr in Iraq, Recife in Brazil, Jeddah and Jubail in Saudi Arabia and in Tripoli Port in Lebanon, which will be operational in April 2016. It also marked another milestone in 2014 with its expansion to the US by signing a long-term agreement to operate the container and multi-cargo terminal at Port Canaveral in Florida. With a current handling activity of over 6 million TEUs, the company has set an ambitious target to triple the volume over the next decade through organic growth across existing businesses, exploring green field opportunities and potential M&A activities.

Learn about how to integrate Apache Camel and Fabric8 into an existing Kubernetes CDI service.

in the previous blog post about solrcloud we’ve talked about the situation when zookeeper connection failed and how solr handles that situation. however, we only talked about query time behavior of solrcloud and we said that we will get back to the topic of indexing in the future. that future is finally here – let’s see what happens to indexing when zookeeper connection is not available. looking back at the old post in the solrcloud – what happens when zookeeper fails? blog post, we’ve shown that solr can handle querying without any issues when connection to zookeeper has been lost (which can be caused by different reasons). of course this is true until we change the cluster topology. unfortunately, in case of indexing or cluster change operations, we can’t change the cluster state or index documents when zookeeper connection is not working or zookeeper failed to read/write the data we want. why we can run queries? the situation is quite simple – querying is not an operation that needs to alter solrcloud cluster state. the only thing solr needs to do is accept the query, run it against known shards/replicas and gather the results. of course cluster topology is not retrieved with each query, so when there is no active zookeeper connection (or zookeeper failed) we don’t have a problem with running queries. there is also one important and not widely know feature of solrcloud – the ability to return partial results. by adding the shards.tolerant=true parameter to our queries we inform solr, that we can live with partial results and it should ignore shards that are not available. this means that solr will return results even if some of the shards from our collection is not available. by default, when this parameter is not present or set to false , solr will just return error when running a query against collection that doesn’t have all the shards available. why we can’t index data? so, we can’t we index data, when zookeeper connection is not available or when zookeeper doesn’t have a quorum? because there is potentially not enough information about the cluster state to process the indexing operation. solr just may not have the fresh information about all the shards, replicas, etc. because of that, indexing operation may be pointed to incorrect shard (like not to the current leader), which can lead to data corruption. and because of that indexing (or cluster change) operation is jus not possible. it is generally worth remembering, that all operations that can lead to cluster state update or collections update won’t be possible when zookeeper quorum is not visible by solr (in our test case, it will be a lack of connectivity of a single zookeeper server). of course, we could leave you with what we wrote above, but let’s check if all that is true. running zookeeper a very simple step. for the purpose of the test we will only need a single zookeeper instance which is run using the following command from zookeeper installation directory: bin/zkserver.sh start we should see the following information on the console: jmx enabled by default using config: /users/gro/solry/zookeeper/bin/../conf/zoo.cfg starting zookeeper ... started and that means that we have a running zookeeper server. starting two solr instances to run the test we’ve used the newest available solr version – the 5.2.1 when this blog post was published. to run two solr instances we’ve used the following command: bin/solr start -e cloud -z localhost:2181 solr asked us a few questions when it was starting and the answers where the following: number of instances: 2 collection name: gettingstarted number of shards: 2 replication count: 1 configuration name: data_driven_schema_configs cluster topology after solr started was as follows: let’s index a few documents to see that solr is really running, we’ve indexed a few documents by running the following command: bin/post -c gettingstarted docs/ if everything went well, after running the following command: curl -xget 'localhost:8983/solr/gettingstarted/select?indent=true&q=*:*&rows=0' we should see solr responding with similar xml: 0 38 *:* true 0 we’ve indexed our documents, we have solr running. let’s stop zookeeper and index data to stop zookeeper server we will just run the following command in the zookeeper installation directory: bin/zkserver.sh stop and now, let’s again try to index our data: bin/post -c gettingstarted docs/ this time, instead of data being written into the collection we will get an error response similar to the following one: posting file index.html (text/html) to [base]/extract simpleposttool: warning: solr returned an error #503 (service unavailable) for url: http://localhost:8983/solr/gettingstarted/update/extract?resource.name=%2fusers%2fgro%2fsolry%2f5.2.1%2fdocs%2findex.html&literal.id=%2fusers%2fgro%2fsolry%2f5.2.1%2fdocs%2findex.html simpleposttool: warning: response: 5033cannot talk to zookeeper - updates are disabled.503 as we can see, the lack of zookeeper connectivity resulted in solr not being able to index data. of course querying still works. turning on zookeeper again and retrying indexing will be successful, because solr will automatically reconnect to zookeeper and will start working again. short summary of course this and the previous blog post related to zookeeper and solrcloud are only touching the surface of what is happening when zookeeper connection is not available. a very good test that shows us data consistency related information can be found at http://lucidworks.com/blog/call-maybe-solrcloud-jepsen-flaky-networks/ . i really recommend it if you would like to know what will happen with solrcloud in various emergency situations.

It's a big week with Dockercon going on, and we have some great updates. At the show, we are demoing UrbanCode Build and Deploy build containers, storing them in registries, and deploying them out through test environments and production across hybrid clouds. Check out this quick overview from the team: For a deep dive on any of it, find the guys at the IBM booth at Dockercon. They'll be happy to show you!

This days I’m reading about Microservices. The idea is great. Instead of building a monolithic script using one language/framowork. We create isolated services and we build our application using those services (speaking HTTP between services and application). That’s means we’ll have several microservices and we need to use them, and maybe sometimes change one service with another one. In this post I want to build one small container to handle those microservices. Similar idea than Dependency Injection Containers. As we’re going to speak HTTP, we need a HTTP client. We can build one using curl, but in PHP world we have Guzzle, a great HTTP client library. In fact Guzzle has something similar than the idea of this post: Guzzle services, but I want something more siple. Imagine we have different services: One Silex service (PHP + Silex) use Silex\Application; $app = new Application(); $app->get('/hello/{username}', function($username) { return "Hello {$username} from silex service"; }); $app->run(); Another PHP service. This one using Slim framework use Slim\Slim; $app = new Slim(); $app->get('/hello/:username', function ($username) { echo "Hello {$username} from slim service"; }); $app->run(); And finally one Python service using Flask framework from flask import Flask, jsonify app = Flask(__name__) @app.route('/hello/') def show_user_profile(username): return "Hello %s from flask service" % username if __name__ == "__main__": app.run(debug=True, host='0.0.0.0', port=5000) Now, with our simple container we can use one service or another use Symfony\Component\Config\FileLocator; use MSIC\Loader\YamlFileLoader; use MSIC\Container; $container = new Container(); $ymlLoader = new YamlFileLoader($container, new FileLocator(__DIR__)); $ymlLoader->load('container.yml'); echo $container->getService('flaskServer')->get('/hello/Gonzalo')->getBody() . "\n"; echo $container->getService('silexServer')->get('/hello/Gonzalo')->getBody() . "\n"; echo $container->getService('slimServer')->get('/hello/Gonzalo')->getBody() . "\n"; And that’s all. You can see the project in my github account.

[This article was written by Alex Harford.] Docker APIs are a convenient way for your systems to talk to Docker infrastructure. But sometimes there are challenges associated with them. I've outlined in this blog the steps you need to take and the items you need to look out for when working with Docker APIs. Initial Docker Setup Ensure you have the latest Docker client installed. It should be v1.6 or newer. [alexh:~/work] docker pull ubuntu latest: Pulling from ubuntu 428b411c28f0: Pull complete 435050075b3f: Pull complete 9fd3c8c9af32: Pull complete 6d4946999d4f: Already exists ubuntu:latest: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security. Digest: sha256:45e42b43f2ff4850dcf52960ee89c21cda79ec657302d36faaaa07d880215dd9 Status: Downloaded newer image for ubuntu:latest [alexh:~/work] docker run -ti ubuntu /bin/bash root@1092e8ca2ead:/# ps PID TTY TIME CMD 1 ? 00:00:00 bash 14 ? 00:00:00 ps root@1092e8ca2ead:/# exit exit Daemons, Registries, Hubs The Docker registry is used to host docker images for download. In the most simple case, it can be a process serving static images. This would be a read-only registry supporting GET operations only. If you need something more complex, you need to use a Docker registry web service. You can [a target="_blank" href="http://www.activestate.com/blog/2014/01/deploying-your-own-private-docker-registry"]run your own private Docker registry or use the public official Docker Hub. The Docker Hub contains a Docker registry, but also includes other features, like user authentication. In our examples, we will run an unauthenticated Docker registry. Setup If you are using standard Docker images, most people will pull from the Docker Hub, which is a publically accessible Docker registry. However, a more complicated service may be talking to private Docker registries running different versions of the API. Let’s assemble a test environment with both versions of the docker registry API so we can see the different ways you can access it. First, pull down two versions of the docker registry from the Docker Hub: docker pull registry:0.9.1 0.9.1: Pulling from registry e9e06b06e14c: Pull complete a82efea989f9: Pull complete 37bea4ee0c81: Pull complete 07f8e8c5e660: Pull complete 1f4ab7282e19: Pull complete 3c27027cdae8: Pull complete 7e0e5314436e: Pull complete 2696504d3685: Pull complete 012772dbb1c6: Pull complete e24d9fce1d00: Pull complete fd2726a79da8: Pull complete bffc32d7113a: Pull complete 0cd49aa0e23c: Pull complete 4e698fa80441: Already exists registry:0.9.1: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security. Digest: sha256:98937757728eecbd72c9276bf711260aa29896f15217ce05be0562287e73232d Status: Downloaded newer image for registry:0.9.1 [alexh:~/work] docker pull registry:2.0.1 2.0.1: Pulling from registry 39bb80489af7: Pull complete df2a0347c9d0: Pull complete 7a3871ba15f8: Pull complete a2703ed272d7: Pull complete 68769176e114: Pull complete ab2ab59d7d1b: Pull complete 882ecee9f360: Pull complete 40de65f8e79f: Pull complete 0c4f9c7d798f: Pull complete ca29675fe853: Pull complete 89d10e9463e5: Pull complete 1a5aa415e484: Pull complete 3ea7a9e93b04: Pull complete 769d811a57fd: Pull complete ae8a4a3af1aa: Pull complete 85cc9a791bb5: Pull complete 9cd2c8646022: Pull complete 048c32c549b9: Pull complete cbbbda28c189: Pull complete 2602c005e534: Pull complete 136beb445cfa: Pull complete 0c5e5ef1d7da: Already exists registry:2.0.1: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security. Digest: sha256:0cd177d687589aff586aa2c66c64d1c25657b8d09cff9e1492192f496e7786c3 Status: Downloaded newer image for registry:2.0.1 The next step is to start them. We will start the v1 registry on port 5000, and the v2 registry on port 6000. The v1 registry occasionally fails when starting due to a lock file race condition, so tell it to restart if necessary. [alexh:~/work] docker run -p 5000:5000 -d --restart=on-failure:3 registry:0.9.1 896c651b9bfa9780b14e3710d20428baab8497c30b9bc89946b192e1d1c145aa [alexh:~/work] docker run -p 6000:5000 -d registry:2.0.1 e09d4204921c732879ee9b7544cd40a25275e0d1f1702cacd954412cfd586ffb [alexh:~/work] docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES e09d4204921c registry:2.0.1 "registry cmd/regist 4 seconds ago Up 3 seconds 0.0.0.0:6000->5000/tcp silly_albattani 896c651b9bfa registry:0.9.1 "docker-registry" 35 seconds ago Up 34 seconds 0.0.0.0:5000->5000/tcp jovial_leakey Understanding Docker Namespaces Docker has a concept of namespaces for its repositories which can be confusing. [a target="_blank" href="https://docs.docker.com/docker-hub/official_repos/"]Official Repositories can be referred to without a username prefix: CentOS Ubuntu Internally these are prefixed by library/. This means that command like docker pull ubuntu:15.10 and docker pull library/ubuntu:15.10 are equivalent. If the name includes a '/' character (samalba/docker-registry), the left side refers to the username, and the right side refers to the image name in their public repository. It gets more complex when accessing private registries. The format becomes HOST:PORT/[USERNAME/]IMAGE. However, you should note that there is no authentication performed at this layer of our docker registry environment: anyone can push, pull, or delete from any 'user'. If the USERNAME is omitted, it is internally treated as being an 'official' image, and prefixed with library/. docker pull 127.0.0.1:5000/library/test-ubuntu Pulling repository 127.0.0.1:5000/library/test-ubuntu FATA[0004] Error: image library/test-ubuntu:latest not found [alexh:~/work] docker tag 0fe5a10d2cf8 127.0.0.1:5000/test-ubuntu [alexh:~/work] docker push 127.0.0.1:5000/test-ubuntu The push refers to a repository [127.0.0.1:5000/test-ubuntu] (len: 1) Sending image list Pushing repository 127.0.0.1:5000/test-ubuntu (1 tags) Image 5c1d0c04c3b8 already pushed, skipping Image 8c63e4ac9a5f already pushed, skipping Image 5fc05c0feaea already pushed, skipping Image 0fe5a10d2cf8 already pushed, skipping Pushing tag for rev [0fe5a10d2cf8] on {http://127.0.0.1:5000/v1/repositories/test-ubuntu/tags/latest} [alexh:~/work] docker pull 127.0.0.1:5000/library/test-ubuntu Pulling repository 127.0.0.1:5000/library/test-ubuntu 0fe5a10d2cf8: Download complete 5c1d0c04c3b8: Download complete 8c63e4ac9a5f: Download complete 5fc05c0feaea: Download complete Status: Image is up to date for 127.0.0.1:5000/library/test-ubuntu:latest In the v2 Docker registry, the [a target="_blank" href="https://docs.docker.com/registry/spec/api/#overview"]URI scheme has changed to allow the repository name to be broken up into multiple components. However, the Docker client does not yet support this flexibility. In the future, you should be able to extend the namespace of your registries, ie `redhat/centos/beta or redhat/fedora/stable. Populating the Registries We'll use Ubuntu 15.10 as our example image: docker pull ubuntu:15.10 15.10: Pulling from ubuntu 5c1d0c04c3b8: Pull complete 8c63e4ac9a5f: Pull complete 5fc05c0feaea: Pull complete 0fe5a10d2cf8: Already exists ubuntu:15.10: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security. Digest: sha256:d569b6ebfc62f35f9792392724bd4a74a4f5f5af10ccbc1880974ae2f0660898 Status: Downloaded newer image for ubuntu:15.10 It needs to be tagged with the new URL in order to push it to the private registries: [alexh:~/work] docker tag ubuntu:15.10 127.0.0.1:5000/ubuntu:15.10 [alexh:~/work] docker tag ubuntu:15.10 127.0.0.1:6000/ubuntu:15.10 [alexh:~/work] docker push 127.0.0.1:5000/ubuntu:15.10 The push refers to a repository [127.0.0.1:5000/ubuntu] (len: 1) Sending image list Pushing repository 127.0.0.1:5000/ubuntu (1 tags) 5c1d0c04c3b8: Image successfully pushed 8c63e4ac9a5f: Image successfully pushed 5fc05c0feaea: Image successfully pushed 0fe5a10d2cf8: Image successfully pushed Pushing tag for rev [0fe5a10d2cf8] on {http://127.0.0.1:5000/v1/repositories/ubuntu/tags/15.10} [alexh:~/work] docker push 127.0.0.1:6000/ubuntu:15.10 The push refers to a repository [127.0.0.1:6000/ubuntu] (len: 1) 0fe5a10d2cf8: Image already exists 5fc05c0feaea: Image successfully pushed 8c63e4ac9a5f: Image successfully pushed 5c1d0c04c3b8: Image successfully pushed Digest: sha256:1f93077ce8f2fa1da8aae87735f395eae93a1c21928d3e2d130717c9aeff177d Note that the output between the v1 registry (on port 5000) and v2 (port 6000) are slightly different, but the result is the same: the Ubuntu image is now available on each registry. Docker Registry APIs At this point, we're able to compare the different APIs. In April 2015, Docker [a target="_blank" href="http://docs.docker.com/v1.6/release-notes/"]released version 1.6 and this included v2 of the Registry. Your software should be aware of the different versions of the Docker Registry API to handle these differences. Let's look at what it takes to download the image layers through the various APIs in order to make an offline cache. First, we'll prepare our environment: [alexh:~/work] export image=ubuntu [alexh:~/work] export tag=15.10 v1 The v1 private registry can be examined at this point: [alexh:~/work] curl -s http://127.0.0.1:5000/v1/repositories/library/$image/tags/$tag | python -m json.tool "0fe5a10d2cf8cdb378a39a81d87b0c8fcfa8fcaaf11bba895a1b6f72baf9a547" export v1_image_id=`curl -s http://127.0.0.1:5000/v1/repositories/library/$image/tags/$tag | sed 's/"//g'` [alexh:~/work] curl -s http://127.0.0.1:5000/v1/images/$v1_image_id/ancestry | python -m json.tool [ "0fe5a10d2cf8cdb378a39a81d87b0c8fcfa8fcaaf11bba895a1b6f72baf9a547", "5fc05c0feaeab977e52b7c2490bffacaba0e3d58e7955b683f271041d3558ad1", "8c63e4ac9a5f31e482d25a149b022209653b5948cb4f045c2ede9331a18e5824", "5c1d0c04c3b846fffd1d70886c956927a5c5f6a1c96f5e9f61c02f2ec1a45a73" ] [alexh:~/work] curl -sSL http://127.0.0.1:5000/v1/images/0fe5a10d2cf8cdb378a39a81d87b0c8fcfa8fcaaf11bba895a1b6f72baf9a547/layer > 0fe5a10d2cf8cdb378a39a81d87b0c8fcfa8fcaaf11bba895a1b6f72baf9a547.tar.gz [alexh:~/work] curl -sSL http://127.0.0.1:5000/v1/images/5fc05c0feaeab977e52b7c2490bffacaba0e3d58e7955b683f271041d3558ad1/layer > 5fc05c0feaeab977e52b7c2490bffacaba0e3d58e7955b683f271041d3558ad1.tar.gz [alexh:~/work] curl -sSL http://127.0.0.1:5000/v1/images/8c63e4ac9a5f31e482d25a149b022209653b5948cb4f045c2ede9331a18e5824/layer > 8c63e4ac9a5f31e482d25a149b022209653b5948cb4f045c2ede9331a18e5824.tar.gz [alexh:~/work] curl -sSL http://127.0.0.1:5000/v1/images/5c1d0c04c3b846fffd1d70886c956927a5c5f6a1c96f5e9f61c02f2ec1a45a73/layer > 5c1d0c04c3b846fffd1d70886c956927a5c5f6a1c96f5e9f61c02f2ec1a45a73.tar.gz v1 on Docker Hub The Docker Hub currently implements the v1 API, but requires an authentication token for certain operations. It also allows multiple endpoints to be returned by the server. We'll take the simple approach of always using the first endpoint: [alexh:~/work] export endpoint=`curl -sSL -o /dev/null -D- "https://index.docker.io/v1/repositories/$image/images" | awk '/X-Docker-Endpoints/{print $2}' | tr -d '\r' | sed 's/,//'` [alexh:~/work] echo $endpoint registry-1.docker.io [alexh:~/work] export token=`curl -sSL -o /dev/null -D- -H 'X-Docker-Token: true' "https://index.docker.io/v1/repositories/$image/images" | tr -d '\r' | awk '/X-Docker-Token/{print $2}'` The token needs to be used for authentication for the rest of the commands, but otherwise they are the same as the v1 private registry: [alexh:~/work] export v1_image_id=`curl -s -H "Authorization: Token $token" https://$endpoint/v1/repositories/library/$image/tags/$tag | sed 's/"//g'` [alexh:~/work] curl -sSL -H "Authorization: Token $token" "https://registry-1.docker.io/v1/images/$v1_image_id/ancestry" | python -m json.tool [ "0fe5a10d2cf8cdb378a39a81d87b0c8fcfa8fcaaf11bba895a1b6f72baf9a547", "5fc05c0feaeab977e52b7c2490bffacaba0e3d58e7955b683f271041d3558ad1", "8c63e4ac9a5f31e482d25a149b022209653b5948cb4f045c2ede9331a18e5824", "5c1d0c04c3b846fffd1d70886c956927a5c5f6a1c96f5e9f61c02f2ec1a45a73" ] [alexh:~/work] curl -sSL -H "Authorization: Token $token" https://$endpoint/v1/images/0fe5a10d2cf8cdb378a39a81d87b0c8fcfa8fcaaf11bba895a1b6f72baf9a547/layer > 0fe5a10d2cf8cdb378a39a81d87b0c8fcfa8fcaaf11bba895a1b6f72baf9a547.tar.gz [alexh:~/work] curl -sSL -H "Authorization: Token $token" https://$endpoint/v1/images/5fc05c0feaeab977e52b7c2490bffacaba0e3d58e7955b683f271041d3558ad1/layer > 5fc05c0feaeab977e52b7c2490bffacaba0e3d58e7955b683f271041d3558ad1.tar.gz [alexh:~/work] curl -sSL -H "Authorization: Token $token" https://$endpoint/v1/images/8c63e4ac9a5f31e482d25a149b022209653b5948cb4f045c2ede9331a18e5824/layer > 8c63e4ac9a5f31e482d25a149b022209653b5948cb4f045c2ede9331a18e5824.tar.gz [alexh:~/work] curl -sSL -H "Authorization: Token $token" https://$endpoint/v1/images/5c1d0c04c3b846fffd1d70886c956927a5c5f6a1c96f5e9f61c02f2ec1a45a73/layer > 5c1d0c04c3b846fffd1d70886c956927a5c5f6a1c96f5e9f61c02f2ec1a45a73.tar.gz v2 API The v2 API works with manifest files that include checksums. It's also slightly simpler. A manifest file for a tag contains all of the layer information, rather than requiring an image ID to be looked up for a tag, and then the ancestry for that image to be looked up. [alexh:~/work] curl -sSL http://127.0.0.1:6000/v2/$image/manifests/$tag | python -c 'import sys, json, pprint; pprint.pprint(json.load(sys.stdin)["fsLayers"])' [{u'blobSum': u'sha256:a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4'}, {u'blobSum': u'sha256:a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4'}, {u'blobSum': u'sha256:d4d342aa9da086ca4b7f7273858072e81021f4379c486223bc4708df6862b55d'}, {u'blobSum': u'sha256:23dc26e1038ae691b1a7e8e0152f974a358c42c929104c18c8e20b6d363c41ca'}, {u'blobSum': u'sha256:7772c716a45a828e124d20bc67199e77f2e63fb62589d0046f974f99b406e107'}] [alexh:~/work] curl -sSL http://127.0.0.1:6000/v2/$image/blobs/sha256:a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4 > a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4.tar.gz [alexh:~/work] curl -sSL http://127.0.0.1:6000/v2/$image/blobs/sha256:d4d342aa9da086ca4b7f7273858072e81021f4379c486223bc4708df6862b55d > d4d342aa9da086ca4b7f7273858072e81021f4379c486223bc4708df6862b55d.tar.gz [alexh:~/work] curl -sSL http://127.0.0.1:6000/v2/$image/blobs/sha256:23dc26e1038ae691b1a7e8e0152f974a358c42c929104c18c8e20b6d363c41ca > 23dc26e1038ae691b1a7e8e0152f974a358c42c929104c18c8e20b6d363c41ca.tar.gz [alexh:~/work] curl -sSL http://127.0.0.1:6000/v2/$image/blobs/sha256:7772c716a45a828e124d20bc67199e77f2e63fb62589d0046f974f99b406e107 > 7772c716a45a828e124d20bc67199e77f2e63fb62589d0046f974f99b406e107.tar.gz We can get the checksum for these files to verify that they are what is described in the manifest file: [alexh:~/work] sha256sum *.tar.gz a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4 a3ed95caeb02ffe68cdd9fd84406680ae93d633cb16422d00e8a7c22955b46d4.tar.gz d4d342aa9da086ca4b7f7273858072e81021f4379c486223bc4708df6862b55d d4d342aa9da086ca4b7f7273858072e81021f4379c486223bc4708df6862b55d.tar.gz 23dc26e1038ae691b1a7e8e0152f974a358c42c929104c18c8e20b6d363c41ca 23dc26e1038ae691b1a7e8e0152f974a358c42c929104c18c8e20b6d363c41ca.tar.gz 7772c716a45a828e124d20bc67199e77f2e63fb62589d0046f974f99b406e107 7772c716a45a828e124d20bc67199e77f2e63fb62589d0046f974f99b406e107.tar.gz The Remote (daemon) API Another API that is available is the Docker daemon running locally. It can be accessed over a Unix socket, or over TCP if the daemon is configured to allow it. [alexh:~/work] echo -e "GET /images/json HTTP/1.0\r\n" | nc -U /var/run/docker.sock | tail -n +6 | python -m json.tool [ { "Created": 1433116930, "Id": "0fe5a10d2cf8cdb378a39a81d87b0c8fcfa8fcaaf11bba895a1b6f72baf9a547", "Labels": {}, "ParentId": "5fc05c0feaeab977e52b7c2490bffacaba0e3d58e7955b683f271041d3558ad1", "RepoDigests": [], "RepoTags": [ "127.0.0.1:6000/ubuntu:15.10", "ubuntu:15.10", "127.0.0.1:5000/ubuntu:15.10" ], "Size": 0, "VirtualSize": 132392276 }, { "Created": 1432704049, "Id": "0c5e5ef1d7dac23c7164ea48faafc79f0c921f6cf87d2d8ea7469832ea31e4ca", "Labels": {}, "ParentId": "136beb445cfa7f48dbe4e36a80a83d4b7945682827fd8bfb1510ac17b6a200c0", "RepoDigests": [], "RepoTags": [ "registry:2.0.1" ], "Size": 0, "VirtualSize": 548626543 }, { "Created": 1432703977, "Id": "4e698fa804417b34b334793bab8a143403be9384e0651067b0c3933fe8d90eb2", "Labels": {}, "ParentId": "0cd49aa0e23cfe176cbea4bf622d552a6f16b21965cf52d633f8c9e27438f52c", "RepoDigests": [], "RepoTags": [ "registry:0.9.1" ], "Size": 0, "VirtualSize": 413940033 } ] A tarball containing all of the layers for a tag can be generated: [alexh:~/work] echo -e "GET /images/get?names=$image:$tag HTTP/1.0\r\n" | nc -U /var/run/docker.sock | tail -n +5 > $image-$tag.tar [alexh:~/work] mkdir tmp [alexh:~/work] tar -C tmp -xf ubuntu-15.10.tar [alexh:~/work] ls -l tmp total 20 drwxr-xr-x 2 alexh alexh 4096 Jun 2 15:33 0fe5a10d2cf8cdb378a39a81d87b0c8fcfa8fcaaf11bba895a1b6f72baf9a547 drwxr-xr-x 2 alexh alexh 4096 Jun 2 15:33 5c1d0c04c3b846fffd1d70886c956927a5c5f6a1c96f5e9f61c02f2ec1a45a73 drwxr-xr-x 2 alexh alexh 4096 Jun 2 15:33 5fc05c0feaeab977e52b7c2490bffacaba0e3d58e7955b683f271041d3558ad1 drwxr-xr-x 2 alexh alexh 4096 Jun 2 15:33 8c63e4ac9a5f31e482d25a149b022209653b5948cb4f045c2ede9331a18e5824 -rw-r--r-- 1 alexh alexh 87 Jun 2 15:33 repositories Conclusions Docker is a great technology and there are a lot of improvements and new features coming out at a rapid pace. Fortunately it's well documented and discussions about bugs are in the open on GitHub. However, there are still some edge cases to be aware of when talking to the Docker APIs. With some good design choices, your applications can be made backwards and forwards compatible, and will be able to use a wide range of Docker client versions and remote APIs.

CoreOS Linux is the operating system for “Super Massive Deployments”. We wanted to see how easily we can get CoreOS logs into Elasticsearch / ELK-powered centralized logging service. Here’s how to get your CoreOS logs into ELK in about 5 minutes, give or take. If you’re familiar with CoreOS and Logsene, you can grab CoreOS/Logsene config files from Github. Here’s an example Kibana Dashboard you can get in the end: CoreOS Kibana Dashboard CoreOS is based on the following: Docker and rkt for containers systemd for startup scripts, and restarting services automatically etcd as centralized configuration key/value store fleetd to distribute services over all machines in the cluster. Yum. journald to manage logs. Another yum. Amazingly, with CoreOS managing a cluster feels a lot like managing a single machine! We’ve come a long way since ENIAC! There’s one thing people notice when working with CoreOS – the repetitive inspection of local or remote logs using “journalctl -M machine-N -f | grep something“. It’s great to have easy access to logs from all machines in the cluster, but … grep? Really? Could this be done better? Of course, it’s 2015! Here is a quick example that shows how to centralize logging with CoreOS with just a few commands. The idea is to forward the output of “journalctl -o short” to Logsene‘s Syslog Receiver and take advantage of all its functionality – log searching, alerting, anomaly detection, integrated Kibana, even correlation of logs with Docker performance metrics — hey, why not, it’s all available right there, so we may as well make use of it all! Let’s get started! Preparation: 1) Get a list of IP addresses of your CoreOS machines fleetctl list-machines 2) Create a new Logsene App (here) 3) Change the Logsene App Settings, and authorize the CoreOS host IP Addresses from step 1) (here’s how/where) Congratulations – you just made it possible for your CoreOS machines to ship their logs to your new Logsene app! Test it by running the following on any of your CoreOS machines: journalctl -o short -f | ncat --ssl logsene-receiver-syslog.sematext.com 10514 …and check if the logs arrive in Logsene (here). If they don’t, yell at us @sematext – there’s nothing better than public shaming on Twitter to get us to fix things. :) Create a fleet unit file called logsene.service [Unit] Description=Logsene Log Forwarder [Service] Restart=always RestartSec=10s ExecStartPre=/bin/sh -c "if [ -n \"$(etcdctl get /sematext.com/logsene/`hostname`/lastlog)\" ]; then echo \"Value Exists: /sematext.com/logsene/`hostname`/lastlog $(etcdctl get /sematext.com/logsene/`hostname`/lastlog)\"; else etcdctl set /sematext.com/logsene/`hostname`/lastlog\"`date +\"%Y-%%m-%d %%H:%M:%S\"`\"; true; fi" ExecStart=/bin/sh -c "journalctl --since \"$(etcdctl get /sematext.com/logsene/`hostname`/lastlog)\" -o short -f | ncat --ssl logsene-receiver-syslog.sematext.com 10514" ExecStopPost=/bin/sh -c "export D=\"`date +\"%Y-%%m-%%d %%H:%M:%S\"`\"; /bin/etcdctl set /sematext.com/logsene/$(hostname)/lastlog \"$D\"" [Install] WantedBy=multi-user.target [X-Fleet] Global=true Activate cluster-wide logging to Logsene with fleet To start logging to Logsene from all machines activate logsene.service: fleetctl load logsene.service fleetctl start logsene.service There. That’s all there is to it! Hope this worked for you! At this point all your CoreOS logs should be going to Logsene. Now you have a central place to see all your CoreOS logs. If you want to send your app logs to Logsene, you can do that, too — anything that can send logs via Syslog or to Elasticsearch can also ship logs to Logsene. If you want some Docker containers & host monitoring to go with your CoreOS logs, just pull spm-agent-docker from Docker Registry. Enjoy!

I have just recorded a 5 minute video that demonstrates running an out of stock example from Apache Camel release, the camel-example-servlet packaged as a docker container and running on a kubernetes platform, such as openshift 3. camel-servlet-example scaled up to 3 running containers (pods) which is easy with kubernetes and fabric8 In this video I have already deployed the example and then demonstrates how we can use the fabric8 web console to manage our application. And also connect to the running container and see inside, such as the Camel routes visually as shown above. Then I run a simple bash script from my laptop that sends a HTTP GET to the Camel example and prints the response. The script runs in a endless loop and demonstrates how kubernetes can easily scale up and down multiple Camel containers and load balance across the running containers. And at the end its even self healing when I force killing docker containers. So I suggest to grab a fresh cup of tea or coffee and sit back and play the 5 minutes video. The video is hosted on vimeo and can be seen from this link.

Docker deployments can be very dynamic with containers being started and stopped, moved around the YARN or Mesos-managed clusters, having very short life spans (the so-called pets) or long uptimes (aka cattle). Getting insight into the current and historical state of such clusters goes beyond collecting container performance metrics and sending alert notifications. If a container dies or gets paused, for example, you may want to know about it, right? Or maybe you’d want to be able to see that a container went belly up in retrospect when troubleshooting, wouldn’t you? Just two weeks ago we added Docker Monitoring (docker image is right here for your pulling pleasure) to SPM. We didn’t stop there — we’ve now expanded SPM’s Docker support by adding Docker Event collection, charting, and correlation. Every time a container is created or destroyed, started, stopped, or when it dies, spm-agent-docker captures the appropriate event so you can later see what happened where and when, correlate it with metrics, alerts, anomalies — all of which are captured in SPM — or with any other information you have at your disposal. The functionality and the value this brings should be pretty obvious from the annotated screenshot below. Like this post? Please tweet about Docker Events and Docker Metrics Monitoring Know somebody who’d find this post useful? Please let them know… Here’s the list of Docker events SPM Docker monitoring agent currently captures: Version Information on Startup: server-info – created by spm-agent framework with node.js and OS version info on startup docker-info – Docker Version, API Version, Kernel Version on startup Docker Status Events: Container Lifecycle Events like create, exec_create, destroy, export Container Runtime Events like die, exec_start, kill, oom, pause, restart, start, stop, unpause Every time a Docker container emits one of these events spm-agent-docker will capture it in real-time, ship it over to SPM, and you’ll be able to see it as shown in the above screenshot. Oh, and if you’re running CoreOS, you may also want to see how to index CoreOS logs into ELK/Logsene. Why? Because then you can have not only metrics and container events in one place, but also all container and application logs, too! If you’re using Docker, we hope you find this useful! Anything else you’d like us to add to SPM (for Docker or anyother integration)? Leave a comment, ping @sematext, or send us email – tell us what you’d like to get for early Christmas!

Last week’s Gartner IT Operations Strategies & Solutions Summit in Orlando, Fla., was exactly what you’d expect—a place to talk about the IT operations issues impacting some of the largest companies in the world. Even so, there were a few interesting surprises. Among them: 1. Bi-modal is big. Not everyone will succeed. Gartner continued to tell its customers to employ two modes of IT—a traditional, slower moving capability for older, typically internal systems of record; and a high-speed, experimental one for new, typically customer-facing Web and mobile apps. “This is a time of experimentation and innovation,” said Gartner VP and distinguished analyst Chris Howard in his opening keynote. Organizations can’t ignore that there are multiple speeds and they should participate in all. Gartner managing VPRonni Colville added that by 2017, 75% of IT orgs will have this “bi-modal” IT capability. See also: Bi-Modal IT: Gartner Endorses Both Disruptive and Conservative Approaches to Technology However, “50% will make a mess of it,” Colville said. Why? Not necessarily because of technology failings, but more often because of a lack of people skills. 2. IT success is all about people. Donna Scott, also a Gartner VP and distinguished analyst, told her keynote audience that “you will be judged on agility, speed, and innovation.” However, the biggest problems Gartner sees for infrastructure and operations team engagement and innovation are lack of time, company culture that’s not conducive to these approaches, and a lack of business skills in IT. More than half of the people responding to an in-room poll said “people” are the part of IT ops that must change first. Not technology. Gartner research director George Spafford underscored similar issues in large organizations trying to use DevOps at scale: people and “human factors” are the biggest concerns from his in-room poll. All these probably contributed to hiring best-selling author Daniel Pink as a keynote speaker on the opening day of the conference. His focus? Not IT or architecture. Instead, he pounded home the importance of influencing people and selling internally. 3. Big orgs are trying DevOps. But the issues are different at scale. In numerous sessions I saw many hands go up when analysts asked, “Who here is trying DevOps?” Clearly, the approach is getting traction in large companies. But there’s lots of learning still to do. In fact, that was Spafford’s biggest bit of advice. “Always be learning,” he said, “trying to see what works and what breaks, especially at scale.” And, even once you’ve had some initial success, keep learning. “If you’ve done ‪DevOps, stay humble,” he advised. 4. Looking to innovative organizations for ideas … analytics on the rise. Many sessions addressed how large organizations are taking on ideas fostered by smaller, more risk-tolerant companies, and offered advice for doing so successfully. In addition to multiple discussions of DevOps, an entire session was devoted to establishing your own “Genius Bar®—a “walk-up IT support center” as explained in this CIO article. As at previous conferences, Gartner research VP Cameron Haight ran several sessions on lessons learned from firms running massive, Web-scale IT systems. “You need lots of data … and access to it inexpensively,” he said. Some commercial monitoring companies (New Relic included!) got a shout out for taking the lessons of Web scale IT to heart in their offerings. In addition, Haight said, “Analytics are increasingly important for application performance monitoring given the huge amount of data now available.” 5. Cloud: Enterprises want it, but aren’t very good at it yet. Gartner research director Dennis Smith talked through the enterprise’s interest in cloud computing. A huge majority of his in-room poll wanted some mix of both public and private cloud, while only 9% wanted to use only a private cloud environment and a measly 4% were looking to move entirely to the public cloud. The most popular choice (41%) was an 80/20 split between private and public cloud infrastructure. “Enterprises don’t make the dean’s list,” for cloud usage, Smith said, earning no more than a C average in his opinion. Large organizations are doing well at visibility, governance, and delivering standardized stacks, he said, but are less skilled at optimizing for these new environments. Still, Smith said the trends point toward enterprises improving on all fronts. 6. Cloud security can be better than yours. Importantly, Gartner VP and distinguished analyst Neil MacDonald gave the cloud a vote of confidence: noting that, for a variety of reasons, “Well-managed public cloud can be more secure than your own data center.” For example, on-premise software can pose serious security risks, he said, because of “deployment lag” where customers are stuck using software releases with unpatched security vulnerabilities. With a cloud-based Software-as-a-Service (SaaS), security updates can be more quickly rolled out to all customers. But cloud security can be different, requiring a shift to information-level security from OS-level security. Best practices include doing away with a huge pool of all-powerful sysadmins in favor of JEA, or “just enough administration,” where sysadmins have just enough privileges to do their job, and no more. An analogous security practice for compute resources is “least privilege,” where apps and microservices can’t talk to each other unless they specifically need to do so. Audience polling supported MacDonald’s optimistic view of cloud security, which suggests that large enterprises may struggle less with their cloud policies moving forward. 7. Containers: Try ’em! Ahead of this week’s DockerCon in San Francisco, Gartner devoted significant airtime to educating the audience on containers and microservices. My summary of ‪Gartner VP and distinguished analyst Tom Bittman’s advice on containers was simple: Try ’em. Now. Complement them with VMs. ‪And Docker (the company) is important, but not the be-all and end-all in this space. Bittman (copping to some deja vu from Gartner presentations he made on server virtualization 13 years ago) noted that while virtualization has been focused on admin and ops functions, containers are focused on value for developers. But because containers are well suited for driving up VM utilization for workloads that share the same OS, we can expect to see more combinations of containers and server virtualization. Finally, Bittman underscored that Gartner doesn’t see containers having much impact on premise, but making a huge difference in the cloud. That doesn’t necessarily fit with what’s been shown in other research, such as this 2015 State of Containers Survey sponsored by VMblog.com and StackEngine, so we’ll want to watch how this plays out. This is all a lot to digest. The Gartner IT Operations Strategies & Solutions Summitacknowledges the importance of dealing with existing IT systems and practices as well as promising new technologies and thinking, and tries to point a way forward. In fact, Haight had a very good quote about microservices that I thought also served to wrap up the entire event: “If you want to run with the big dogs, you need to rethink application architecture,” he said. That can be very difficult for an enterprise to fully implement … but also very appealing. Note: Al Sargent contributed to this post. All product and company names herein may be trademarks of their registered owners. Server, tortoise and hare, business team, and cloud security images courtesy ofShutterstock.com.

Originally written by David Brimley. The Death Spiral. A new feature in the 3.5 release of Hazelcast is the Cluster Quorum. In this instance we’re not talking about a Quorum in its traditional distributed systems sense, think of a Cluster Quorum as a kind of gatekeeper, protecting your cluster during times of unexpected member loss. You can use Cluster Quorums to restrict operations on Maps or indeed the entire cluster based upon environmental criteria. This sounds great you say, but I’m still not sure how this can help me? OK. Let's take a look at a scenario… Imagine a cluster that has a very high number of writes to a certain map. We also have other maps that are not updated quite so frequently and all the while we have hundreds of clients all reading from the cluster but not at the same frequency as the data that is entering the system. In normal circumstances if a machine or a number of machines were to die in the cluster we may still have enough memory available to store our data, but the amount of threads available to process requests would be reduced. We now have less cores available and the partition threads in the cluster could quickly become overwhelmed by the one map that is updated rapidly. This could mean other clients becoming starved of threads, unable to service requests. It’s also possible that the remaining members would become so consumed that they’re unable to respond to membership pings, the knock on effect could result in the member being forced out of the cluster on the assumption that it is dead. To protect the rest of the cluster in the event of member loss we need a way to stop the writes to the high frequency map whilst allowing operations to the other data structures. We can then continue to provide a good service to our other users whilst the crashed machines are restored to the cluster. Bring on the Quorum! As of Hazelcast 3.5 we now have the ability to restrict operations on distinct data structures. We do this via a Quorum configuration. We observed that other IMDG products provide Quorums that have protection at a cluster level,we decided to go one step further and provide Quorum protection around data structures as well. In the example below we create a very simple Quorum on the default map. The ‘default’ map in Hazelcast is the configuration used if no other match is found. In this instance no operations will be allowed unless the cluster has a minimum of 3 members. You’ll also note that the Quorum configuration is separate from the Map. This means that you can have multiple Quorums in a cluster attached to many different structures. If the Quorum thresholds are not satisfied then a QuorumException is thrown when we try to interact with the default map in any way. Be it from a client or another member. 3 quorumRuleWithThreeNodes Quorum Functions It’s simple to set up a Quorum check based on cluster size as we’ve seen above, but if you want to make a slightly more complex check you can do this by applying a Quorum Function. QuorumConfig quorumConfig = new QuorumConfig(); quorumConfig.setName("MyQuorum"); quorumConfig.setEnabled(true); quorumConfig.setType(QuorumType.WRITE); quorumConfig.setQuorumFunctionImplementation(new QuorumFunction() { @Override public boolean apply(Collection members) { return (members.size() >= 3) && (someOtherExternalClusterState); } }); In the example above we use Configuration API to set-up the Quorum to disallowwrites if the boolean returned from the QuorumFunction is false. In the function we test if the size of the cluster is greater than 3 and also if a variable namedsomeOtherExternalClusterState is equal true. You now get the idea that by using a function you can test for other state and not just cluster member. Listen In. Another nice feature of Quorums is the ability to listen in to Quorum Events. You can register a new callback interface called not surprisingly a QuorumListener. Quorum listeners are local to the node that they are registered, so they receive only events occurred on that local node. 3 com.company.quorum.ThreeNodeQuorumListener quorumRuleWithThreeNodes The QuorumListener has just one method that is called passing you aQuorumEvent. package com.hazelcast.quorum; import java.util.EventListener; /** * Listener to get notified when a quorum state is changed */ public interface QuorumListener extends EventListener { /** * Called when quorum presence state is changed. * * @param quorumEvent provides information about quorum presence and current member list. */ void onChange(QuorumEvent quorumEvent); } The QuorumEvent itself allows you to determine if a Quorum has been established or if it has been lost via its isPresent() method call. Additionally it provides the required cluster members to form a quorum and also the current membership list. Query the Quorums. Above we saw how we could receive callbacks, but in some cases we may just wish to make an immediate check to see if the Quorum is established or not. We can do this via the QuorumService. HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance(config); QuorumService quorumService = hazelcastInstance.getQuorumService(); Quorum quorum = quorumService.getQuorum(quorumName); boolean quorumPresence = quorum.isPresent(); In Conclusion The Cluster Quorum feature is another important tool for you to manage your cluster. In future versions of Hazelcast there are plans to add other data structures, for example you’ll be able to protect operations against Topics or Queues.

[This article was written by Andrew Marshall] We’ve been talking a lot about Docker over the past few weeks—with good reason. Docker’s explosive growth in popularity within the enterprise has enabled new distributed application architectures and with it a need for app-centric monitoring of your Docker containers within the context of the rest of your infrastructure. We’re thrilled to announce today that New Relic’s Docker monitoring is now generally available to New Relic customers, just in time for DockerCon 2015! (And as we noted last week, New Relic’s Docker monitoring solution has been selected by Docker for its Ecosystem Technology Partner program as a proven container monitoring solution.) Why app-centric monitoring? If you’re a software business using Docker containers, chances are you’ve done so to gain efficiencies from your system resources or portability across environments to shorten the cycle between writing and running code. Either way, adding Docker containers to your app development meant a new tier of infrastructure to monitor, which equated to a “black box” in your data—one that you had no visibility into from a monitoring perspective, Docker monitoring with New Relic is designed to “fix” this lack of monitoring visibility by adding an app-centric view of Docker containers to the existing New Relic Servers interface you already use. Now, instead of having a gap between the application and server monitoring views, we’ve added the ability to see containers with the same “first-class“ experience as you would with virtual machines and servers. You can now drill down from the application (which is really what you care about) to the individual Docker container, and then to the physical server. No more blind spots! As we strive to do with all of our products, we took the approach of “important” over “impressive” when it comes to the container information we provide to users. Based on direct feedback from customers, we’ve tried to take the mystery out of finding the right container to help you get back to developing your applications. As the way people use containers changes over time, we plan to continue to listen to our customers to help shape how we approach Docker container monitoring. Restoring 360-degree view of your application environment One example of how app-centric monitoring can impact a team moving to microservices or distributed application environments is Motus, a mobile workforce management company. Motus has been a New Relic customer for more than four years and recently has been shifting to a microservices architecture with approximately 95% of its production workload now running in Docker containers. While Docker helpd Motus gain speed and agility while reducing infrastructure complexity, the link between the application and what was happening with the container it was running on was broken. During the trial of New Relic’s Docker monitoring, Motus was able to more easily identify which container an app was running on, all the way down to the node. That was a big help when they needed to investigate an issue and determine if a new container was required.. During the beta alone, Motus estimates that using New Relic helped them to reduce the time to investigate and fix problems with its Docker containers by 30%! Motus isn’t just using New Relic to diagnose when a problem occurs. Docker monitoring with New Relic has helped Motus analyze and “right size” its containers for the application to better allocate resources for performance and budget. Get started with New Relic’s Docker monitoring today, for more information, please stop by our booth at DockerCon, June 22-23 in San Francisco! Resources: Motus Docker Monitoring Case Study Docker Monitoring with New Relic Enabling Docker Monitoring with New Relic Docker in the New Relic Community Forum

Written by Stephane Combaudon. A question I often hear when customers want to set up a production PXC cluster is: “How many nodes should we use?” Three nodes is the most common deployment, but when are more nodes needed? They also ask: “Do we always need to use an even number of nodes?” This is what we’ll clarify in this post. This is all about quorum I explained in a previous post that a quorum vote is held each time one node becomes unreachable. With this vote, the remaining nodes will estimate whether it is safe to keep on serving queries. If quorum is not reached, all remaining nodes will set themselves in a state where they cannot process any query (even reads). To get the right size for you cluster, the only question you should answer is: how many nodes can simultaneously fail while leaving the cluster operational? If the answer is 1 node, then you need 3 nodes: when 1 node fails, the two remaining nodes have quorum. If the answer is 2 nodes, then you need 5 nodes. If the answer is 3 nodes, then you need 7 nodes. And so on and so forth. Remember that group communication is not free, so the more nodes in the cluster, the more expensive group communication will be. That’s why it would be a bad idea to have a cluster with 15 nodes for instance. In general we recommend that you talk to us if you think you need more than 10 nodes. What about an even number of nodes? The recommendation above always specifies odd number of nodes, so is there anything bad with an even number of nodes? Let’s take a 4-node cluster and see what happens if nodes fail: If 1 node fails, 3 nodes are remaining: they have quorum. If 2 nodes fail, 2 nodes are remaining: they no longer have quorum (remember 50% is NOT quorum). Conclusion: availability of a 4-node cluster is no better than the availability of a 3-node cluster, so why bother with a 4th node? The next question is: is a 4-node cluster less available than a 3-node cluster? Many people think so, specifically after reading this sentence from the manual: Clusters that have an even number of nodes risk split-brain conditions. Many people read this as “as soon as one node fails, this is a split-brain condition and the whole cluster stop working”. This is not correct! In a 4-node cluster, you can lose 1 node without any problem, exactly like in a 3-node cluster. This is not better but not worse. By the way the manual is not wrong! The sentence makes sense with its context. There could actually reasons why you might want to have an even number of nodes, but we will discuss that topic in the next section. Quorum with multiple data centers To provide more availability, spreading nodes in several datacenters is a common practice: if power fails in one DC, nodes are available elsewhere. The typical implementation is 3 nodes in 2 DCs: Notice that while this setup can handle any single node failure, it can’t handle all single DC failures: if we lose DC1, 2 nodes leave the cluster and the remaining node has not quorum. You can try with 4, 5 or any number of nodes and it will be easy to convince yourself that in all cases, losing one DC can make the whole cluster stop operating. If you want to be resilient to a single DC failure, you must have 3 DCs, for instance like this: Other considerations Sometimes other factors will make you choose a higher number of nodes. For instance, look at these requirements: All traffic is directed to a single node. The application should be able to fail over to another node in the same datacenter if possible. The cluster must keep operating even if one datacenter fails. The following architecture is an option (and yes, it has an even number of nodes!): Conclusion Regarding availability, it is easy to estimate the number of nodes you need for your PXC cluster. But node failures are not the only aspect to consider: Resilience to a datacenter failure can, for instance, influence the number of nodes you will be using.