Is it that important to plan migration to K8S?

Any journey must start with a comprehensive map and a clear understanding of the destination, and the transition to Kubernetes is no different. One of the most common mistakes businesses make when migrating to Kubernetes is not investing enough time and resources in proper planning and understanding the complexities of the system. Kubernetes is a powerful and flexible tool that can orchestrate containers at scale, but it also comes with a steep learning curve and many intricacies.

Firstly, getting your team up to speed with Kubernetes is vital. This includes understanding its basic components such as Pods, Services, and Deployments, and more advanced topics such as ConfigMaps, Secrets, StatefulSets, and Ingress Controllers. This knowledge helps to ensure that your team can effectively manage and troubleshoot the system in the long run. It's often beneficial to provide formal training and hands-on experience before embarking on the migration. In the initial stages, it can be beneficial to experiment with Kubernetes by deploying less critical, non-production applications. This approach provides a sandbox where your team can make mistakes and learn without the fear of disrupting business operations.

Secondly, thorough planning is crucial. One aspect of planning is understanding your applications in-depth. Kubernetes might not be the best solution for all types of applications, especially legacy applications that weren't designed with the cloud-native paradigm in mind. Therefore, a thorough compatibility check for each application is necessary to identify potential challenges and work out mitigation plans. For example, applications that maintain state in local file systems can encounter issues since containers in Kubernetes are ephemeral by nature.

A good migration plan also includes a detailed inventory of application dependencies, which will allow you to sequence the migration in a way that minimizes disruption. It should outline how you will handle data migration, which can be one of the most complex aspects of this process. It's also critical to have a rollback strategy in case things don't go as expected. Kubernetes provides several mechanisms for rolling updates and rollbacks, and understanding how to use them is important.

Moreover, consider how you will structure your Kubernetes clusters and namespaces and which configuration management practices you will follow. Planning a namespace structure may not sound like an important step, but believe me, it is. At the moment Kubernetes does not support namespace renaming. That means if the logic on how to name namespaces or divide applications between namespaces changes, you will have no choice but to perform time consuming and error-prone operation of manually moving resources from one namespace to another one. Besides, you’ll have to fix your CI/CD pipelines for your deployment strategy to fit into new cluster structure.

Also, Kubernetes has its own way of managing configuration and secrets, and understanding these practices early on will save a lot of headache later.

Lastly, don't underestimate the need for infrastructure readiness. Kubernetes can run on a variety of environments, from on-premises data centers to public clouds, and even hybrid environments. Each comes with its own set of considerations. For example, if you're deploying on a public cloud, you need to consider the cloud provider's specific features, pricing models, and service limits.

In summary, the transition to Kubernetes is not merely a technical migration; it's a shift in mindset and approach. It involves understanding a new set of concepts and practices and rethinking how applications are developed and deployed. Businesses that invest the time in comprehensive training and detailed planning will be much better positioned for a successful migration.