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InnoDB Cluster in a Nutshell Part 3: MySQL Shell

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InnoDB Cluster in a Nutshell Part 3: MySQL Shell

Let's look at the final post in this series and discuss the final component, MySQL Shell.

· Database Zone ·
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Welcome to the third part of this series. I'm glad you're still reading, as hopefully, this means you find this subject interesting at least. Previously we presented the first two components of MySQL InnoDB Cluster: Group Replication and MySQL Router and now, we will discuss the last component, MySQL Shell.

MySQL Shell

This is the last component in the cluster, and I love it. Oracle has created this tool to centralize cluster management, providing a friendly, command-line based user interface.

The tool can be defined as an advanced MySQL shell, which is much more powerful than the well known MySQL client. With the capacity to work with both relational and document (JSON) data, the tool provides an extended capability to interact with the database from a single place.

MySQL Shell is also able to understand different languages:

  • JavaScript (default), which includes several built-in functions to administer the cluster-create, destroy, restart, etc.-in a very easy way.
  • Python, which provides an easy way to write Python code to interact with the database. This is particularly useful for developers who don't need to have SQL skills or run applications to test code.
  • SQL, which works in classic mode to query the database as we used to do with the old MySQL client.

A very interesting feature provided with MySQL Shell is the ability to establish different connections to different servers/clusters from within the same shell. There is no need to exit to connect to a different server, just issuing the command \connect will make this happen. As DBA, I find this pretty useful when handling multiple clusters/servers.

Some of the features present in this tool:

  • Capacity to use both Classic and X protocols.
  • Online switch mode to change languages (JavaScript, Python and SQL)
  • Auto-completion of commands using tab, a super expected feature in MySQL client.
  • Colored formatting output that also supports different formats like Table, Tab-separated and JSON formats.
  • Batch mode that processes batches of commands allowing also an interactive mode to print output according to each line is processed.

Some Sample Commands

Samples of new tool and execution modes:

 #switch modes
\sql
\js
\py
#connect to instance
\connect user@host:[port]
#create a cluster (better to handle through variables)
var cluster=dba.createCluster('percona')
#add instances to cluster
cluster.addInstance(‘root@192.168.70.2:3306’)
#check cluster status
cluster.status()
#using another variable
var cluster2=dba.getCluster(‘percona’)
cluster.status()
#get cluster structure
cluster.describe()
#rejoin instance to cluster - needs to be executed locally to the instance
cluster.rejoinInstance()
#rejoin instance to cluster - needs to be executed locally to the instance
cluster.rejoinInstance()
#recover from lost quorum
cluster.forceQuorumUsingPartitionOf(‘root@localhost:3306’)
#recover from lost quorum
cluster.rebootClusterFromCompleteOutage()
#destroy cluster
cluster.dissolve({force:true});

Personally, I think this tool is a very good replacement for the classic MySQL client. Sadly, MySQL server installations do not include MySQL shell by default, but it is worth getting used to. I recommend you try it.

Conclusion

We finally reached the end of this series. I hope you have enjoyed this short introduction to what seems to be Oracle's bid to have a built-in High Availability solution based on InnoDB. It may become a good competitor to Galera-based solutions. Still, there is a long way to go, as the tool was only just released as GA (April 2018). There are a bunch of things that need to be addressed before it becomes consistent enough to be production-ready. In my personal opinion, it is not-yet. Nevertheless, I think it is a great tool that will eventually be a serious player in the HA field as it's an excellent, flexible and easy to deploy solution.

Compliant Database DevOps and the role of DevSecOps DevOps is becoming the new normal in application development, and DevSecOps is now entering the picture. By balancing the desire to release code faster with the need for the same code to be secure, it addresses increasing demands for data privacy. But what about the database? How can databases be included in both DevOps and DevSecOps? What additional measures should be considered to achieve truly compliant database DevOps? This whitepaper provides a valuable insight. Get the whitepaper

Topics:
database ,innodb cluster ,mysql ,shell

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