Kubernetes migration strategy and best practices

A Kubernetes migration strategy consists of a step-by-step plan for moving applications and workloads to a containerized environment, including best practices for a successful outcome.

As businesses modernize applications and adopt cloud-based technologies like microservices, they need container orchestration platforms to reliably and efficiently manage hybrid cloud and multicloud workloads.

As the dominant orchestration platform, Kubernetes enables enterprises to migrate their cloud journeys, facilitating the transition of legacy applications to cloud-native environments.

According to a 2024 Cloud Native Computing Foundation (CNCF) study, cloud-native adoption has reached 89%, with 93% of organizations now using, piloting or evaluating Kubernetes.¹

To carry out a seamless Kubernetes migration, organizations need a robust strategy that involves careful planning designed to capture business and technology opportunities while overcoming challenges.

Originally developed by Google, Kubernetes is an open source container orchestration platform maintained by the Cloud Native Computing Foundation (CNCF) since 2015. Also known as k8s or kube, this platform schedules and automates the deployment, management and scaling of containerized applications.

Before Kubernetes, applications typically ran on dedicated servers or virtual machines (VMs), which made scaling expensive and time-consuming.

In modern containerized settings, a runtime engine (typically Docker) allows developers to build, deploy, run, update and manage containers. Kubernetes provides the orchestration layer needed to manage hundreds or thousands of containers at scale. Today, Docker and Kubernetes are the leading containerization tools.

Kubernetes deployment occurs through clusters made up of nodes—each representing a physical machine or VM. Every cluster has a main node that manages a control plane (including the API server and etcd database). Kubernetes applications run in pods, which are the smallest deployable units. They typically contain Linux-based containers that share storage and other resources.

Key features of Kubernetes include deployments for managing app lifecycles and replica sets, DNS and networking for service delivery, and namespaces for resource isolation. The Kubernetes API server (accessed through the kubectl command-line tool) manages configuration and orchestrates communication between components. Persistent volumes handle storage needs.

Kubernetes is open source, which allows organizations to avoid vendor lock-in. DevOps and other teams benefit from a global community that contributes improvements and security patches. All major cloud service providers offer managed Kubernetes services, including Amazon Web Services (AWS), Microsoft Azure, Google Cloud Platform and IBM Cloud®.

A Kubernetes migration delivers both technical and organizational benefits, including:

• Better resource use and cost efficiency
• Improved reliability and high availability
• Faster deployment
• Enhanced team productivity and autonomy

Kubernetes autoscales applications up or down based on demand. For instance, during peak traffic periods, such as a flash sale on an e-commerce website, it spins up more pods to handle load balancing. When the sale is over and demand decreases, Kubernetes scales back down to conserve resources.

Kubernetes helps keep apps stable and available through distribution across clusters and automatic recovery from failures. This helps maintain high availability.

Kubernetes enables continuous delivery at scale to help streamline workflows and allow teams to create changes whenever needed. Rolling updates deploy new versions gradually, monitoring for issues before completing the rollout. If problems emerge, rollbacks happen quickly.

With Kubernetes, teams own specific services and can work independently. This includes deploying on independent schedules, making technology choices that fit their needs and innovating at the right pace. 

Platform teams provide shared services like monitoring, logging and a service mesh that all teams use, creating consistency without constraining innovation.

Successful migrations begin with thorough planning that involves the following steps:

1. Assess your current environment.
2. Evaluate team skills and training needs.
3. Choose your migration approach.
4. Plan your cluster strategy.

Start by cataloging your existing applications, infrastructure and dependencies. Identify which applications are good candidates for early migration. Typically, stateless applications with well-defined APIs work best as starting points, while stateful apps require more planning.

Document dependencies between applications, including databases, message queues and external services that need consideration during migration.

Evaluate your current infrastructure to determine whether a managed Kubernetes service from a cloud provider or a self-hosted solution makes more sense for your organization. Consider factors like internal expertise, compliance requirements and budget constraints.

Assess your team’s current capabilities with containers, Kubernetes and cloud-native practices.

According to an IBM Institute for Business Value 2023 report, approximately 58% of global decision-makers report that cloud skills remain a considerable challenge.

Identify skill gaps early and develop training plans that include hands-on experience.

Decide between different migration strategies based on application characteristics and business priorities. A lift-and-shift approach containerizes existing applications with minimal changes, allowing faster migration but potentially missing optimization opportunities. Refactoring applications to be cloud-native takes longer but delivers better performance, scalability and cost efficiency.

Many organizations adopt a phased approach. This approach entails starting with simple applications to build experience, then tackling more complex workloads as team expertise grows.

Determine whether you should use a single cluster or multiple clusters in your new environment. Single clusters are simpler to manage but might not meet requirements for isolation, compliance or geographic distribution. Multiple clusters provide better isolation and can improve reliability, but require more sophisticated configuration management that uses tools like Helm charts or Kustomize.

After the planning phase, Kubernetes migration can begin, guided by these best practices:

1. Ready applications for Kubernetes.
2. Build CI/CD pipelines for automated deployments.
3. Monitor and log effectively.
4. Secure Kubernetes clusters.

Start by building container images with multi-stage builds. This technique keeps build dependencies separate from what runs in production, shrinking your image size and reducing security vulnerabilities.

Run containers as non-root users. In this case, if something gets compromised, the damage stays limited.

Use consistent tagging and organize your registry clearly so that you can easily track versions.

Proper health checks help Kubernetes manage your applications effectively. Liveness probes tell Kubernetes whether a pod needs to restart, while readiness probes indicate when pods can accept traffic.

Applications should expose endpoints that verify application health by checking database connectivity, external dependencies or internal state.

For networking, configure service discovery and load balancing by using Kubernetes services so applications can find dependencies through service names rather than hardcoded IP addresses.

For external traffic, implement Ingress resources with appropriate controllers that handle SSL termination and routing.

Externalize all configuration from application code by using YAML files. Use ConfigMaps for non-sensitive configuration and Secrets for sensitive data like database credentials and API keys, enabling the same container image to run across development, staging and production with different configurations.

Build CI/CD pipelines that handle everything from code commit to production deployment, with automated testing that includes unit tests, integration tests and deployment verification. Container images get built automatically and pushed to registries with proper versioning.

Deploy comprehensive monitoring covering resource use (CPU, memory and storage), app performance and business metrics, with dashboards for visualization. Centralized logging helps debug issues across many pods and services.

Use role-based access control (RBAC) for defining permissions, network policies to control traffic between pods, and encryption for data at rest and in transit. Scan container images regularly for vulnerabilities and keep base images updated.

Even well-planned Kubernetes migrations face obstacles. On-premises legacy applications often weren’t designed for containerized environments and might rely on outdated configurations, specific server setups or local storage that don’t work in Kubernetes. External systems like databases and third-party services also add complexity. Thorough testing and validation in staging environments help identify and resolve compatibility issues before production.

Protecting data is paramount. Run old and new systems in parallel temporarily, syncing data between environments and validating functionality before fully cutting over to Kubernetes. This running in parallel helps minimize downtime and reduce data loss.

Cloud providers and other technology companies offer a range of Kubernetes migration tools and services, including the following.

Cloud service providers offer managed services for assessing workloads, containerization and automated deployment. For example, Amazon EKS, Microsoft Azure AKS and IBM Cloud Kubernetes Service all offer migration services.

Also, infrastructure-as-code (IaC) tools like Terraform help developers automate cluster provisioning and add-on installation and configuration management.

These tools provide monitoring, observability and troubleshooting capabilities so teams can gain insights into the behavior, health and performance of their Kubernetes environments.

Technology and consulting firms provide Kubernetes expertise that complements migration tools. Such services can guide strategic decisions from initial assessment through post-migration optimization, helping organizations navigate complex technical and organizational challenges.