Migrating from OpenShift 3 to 4

Benefits of OpenShift 4

OpenShift Container Platform 4 represents a significant change in the way that OpenShift Container Platform clusters are deployed, managed, and developed on. OpenShift Container Platform 4 includes new technologies and functionality, for both developers and cluster administrators.  Operators, Serverless, Service Mesh, and Red Hat Enterprise Linux CoreOS (RHCOS), are all new to OpenShift 4 and are redefining what’s possible with the next generation of Kubernetes platforms. This technology shift enables clusters to self-manage functions previously performed by administrators and empower developers to innovate on a consistent and stable platform that is simple to install and scale.

• Operators:  implement and automate common Day-1 (installation, configuration, etc) and Day-2 (re-configuration, update, backup, failover, restore, etc.) activities in a piece of software running inside your OpenShift cluster, by integrating natively with Kubernetes concepts and APIs.

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• Red Hat Serverless:  enables an application to consume only the compute resources necessary and can automatically scale up or down based on use. This removes the overhead of server provisioning and maintenance from the developer, letting them focus on application development instead.

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• Red Hat Service Mesh:  is a way to control how different parts of an application share data with one another through a dedicated infrastructure layer built right into an app. This visible infrastructure layer can track how different parts of an app interact, so optimizing communication and avoiding downtime becomes easier as an app grows.

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• Red Hat Enterprise Linux CoreOS: combines the ease of over-the-air updates from Container Linux with the Red Hat Enterprise Linux kernel to deliver a more secure, easily managed container host.

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Moving from OpenShift 3 to OpenShift 4

The migration process from OpenShift 3 to 4 can be completed in 5 steps:

1. Spin up a new cluster running OpenShift 4.
2. Configure the new OpenShift 4 cluster.
3. Create a migration plan which includes how to handle data from the applications that are being migrated.
4. Run migration plan.
5. Move your DNS or Load-balancer configuration to your new cluster.

Red Hat has built several new tools that integrate the best of open source projects with slick users interfaces to simplify this process and reduce the opportunity for human error. Check out the official documentation to learn more about the migration process and how to utilize the migration tooling.

Migration tools

Control Plane Migration Assistance Tool

The Control Plane Migration Assistance tool helps you configure the new cluster OCP4 cluster that will be the destination for the applications that are being migrated from your existing OCP 3 cluster. This tool reduces the possibility for human error in the configuration process, matching when possible the existing settings in the source cluster. It also allows you to review the resources that will be applied to the new cluster.

Cluster Application Migration Tool (CAM)

The Cluster Application Migration tool (CAM) migrates stateful and stateless applications from the source cluster on OCP 3 to a destination cluster running the latest OpenShift. It also can migrate applications between OCP 4 clusters. It is installed on your destination cluster via an Operator. Through the rich user interface take advantage of the simplified, customizable workflows. Decide which applications to start with and which migration approach best fits each application and your needs.