Cloud Migration Best Practices: How to Move Your Project to Kubernetes
The time for the big move to the cloud has come. You know which applications you're taking, but how will you pack them?
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Moving your app or web services to the cloud is more of a must than an option these days. The cloud infrastructure we have today is not only more capable and more stable, but also more scalable. By moving to the cloud, you gain a lot of benefits while also significantly reducing operational stress and costs.
A more popular option now is to move to a container-based cloud environment, with Kubernetes being the most popular method to do so — and the most scalable in the long run. There are three approaches you can take and certain best practices to follow, which we are going to look into in this article.
Before we get to the best practices and methods you can use to migrate to Kubernetes, it is worth taking the time to understand why the container-based environment provided by Kubernetes is the way to go. For starters, Kubernetes offers the most flexibility when it comes to setting up your cloud environment.
Kubernetes has two major parts: the master cluster and nodes acting as containers for your services. The way these two elements are set up allows for better availability and reliability. While the nodes handle specific tasks and parts of your app, the master cluster deals with things such as managing networks and other resources.
The two-part setup also means you can make changes to your nodes without affecting the entire cluster. When you need to update a particular service, for example, you can create a new node, implement the update, and then tell the master cluster to use the new node instead of the old one. The approach minimizes downtime from the moment you migrate to Kubernetes.
There is also the fact that Kubernetes is immensely flexible. There are no strict rules on how nodes need to be set up in relation to one another. As long as the master cluster is configured to use the nodes correctly, your app or web service will continue to run smoothly.
It is easy to see why Kubernetes is so popular. If you are thinking of migrating to a container-based environment, Kubernetes is the way forward.
Migration Strategies: Three Plans of Attack
There are three ways you can migrate your app to Kubernetes. Rehosting, also known as lift-and-shift, is perhaps the simplest approach of them all. You basically take your web service or app in its entirety and move it to a Kubernetes cluster.
This means, if needed, you simply wrap Docker around your app and then configure Kube YAML files to deploy it. A rehost doesn’t involve making changes to the app as well, which is why this method is the fastest way to move to Kubernetes.
Rehosting, however, may not be the most efficient (or effective) way to utilize the cloud environment offered by Kubernetes. You don’t benefit from all the flexibility of Kubernetes right away. But it is a good first step to take since you can continue to break down services and parts of the app into additional nodes once the initial migration is completed.
Replatforming is the next approach you can use to migrate to Kubernetes. Rather than moving the entire app in its present state, you prepare the app and make some basic changes to the way it runs. This usually involves breaking down services into individual container and pods and separating different functions into individual containers. I’ve seen several times that using the same app with different configs is a quick way to replatform and configure services.
Replatforming takes more time to complete than rehosting. This is due to the fact that adapting apps to a container-based cloud environment is not always a straightforward process. The process can be made simpler with the help of a local Kubernetes cluster and Minikube.
The app can continue to run while you work on a compartmentalized version for migration purposes. Once the updated version is ready and the service cluster is laid out, migrating to a cloud cluster like GKE or Azure becomes a lot easier to complete. You can even do thorough testing inside Minikube to ensure a smoother transition.
Refactoring is the most advanced approach you can take when migrating to Kubernetes. Unlike the previous two approaches, the entire app and the services that support it are modified to better suit the new compartmentalized environment.
In most cases, a refactor involves rearchitecting the entire app to take full advantage of the cloud environment. For instance, you can rebuild services using cloud-native frameworks that are designed to work with Kubernetes, such as Knative. Refactoring lets you go as far as running serverless workloads in the cloud.
As a tradeoff, the migration process takes longer and consumes more resources. At the end of the process though, you have a fully scalable app that takes advantage of all the gains offered by Kubernetes. We only tend to recommend this process if you need to reflect your code base to support a major version upgrade.
So, which approach is best for you? The answer to this depends on your migration objectives, the app you want to migrate to the cloud, and the way the app is currently configured. Review these approaches from your perspective to determine the best course of action when moving to Kubernetes.
This post was originally published here.
Published at DZone with permission of Stefan Thorpe, DZone MVB. See the original article here.
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