General Tech

How to migrate OpenShift 3 to OpenShift 4

9. Oct 2020

Migrating OpenShift Container Platform (OCP) 3 to 4: learn about possible migration paths and why you should make the move to the new version of OpenShift.

Recap: what is OpenShift?

Red Hat OpenShift is a hybrid cloud, enterprise Kubernetes application platform for developers and business applications.
OpenShift provides a secure and stable platform for container-based deployments without the need for big IT investments. This means that much needed legacy applications can be used alongside new cloud native and container-based ones.
Red Hat OpenShift is a Kubernetes distribution. An extensive article with more details about Kubernetes and how Kubernetes compares to OpenShift can be found here.
OpenShift consists of platform, application, and developer services. It is used to manage workloads, build cloud-native apps, and to boost the productivity of developers.

(image: © Red Hat

What’s new in OpenShift 4?

OpenShift 4 was introduced at the Red Hat Summit in May 2019. In this major release, Red Hat redefines Kubernetes for the enterprise through full stack automation. OpenShift 4 includes new technologies and functionality that results in self-managing, flexible, and automated clusters.
New key elements of OpenShift 4 include:

  • Immutable Red Hat Enterprise Linux CoreOS;
  • Operator framework;
  • OpenShift service mesh; and
  • Knative framework.

OpenShift 4 is Kubernetes at its core and in this release, Red Hat has completely re-architected how OpenShift is installed, upgraded and managed, introducing innovations such as Kubernetes Operators. Operators automate life cycle management of containerized applications with Kubernetes, and drives installation and upgrades of OpenShift and all of its services. This includes Kubernetes core services, along with Prometheus, Grafana, Elasticsearch, software-configured networking, storage, registry and other components of the OpenShift Kubernetes platform. OpenShift 4 is an Operator-driven platform that delivers full-stack automation from top to bottom.
OpenShift 4 also offers multiple cluster management across multiple clouds, and enables hybrid cloud services with Operators & OperatorHub. OpenShift 4 is designed to deliver a unified experience across hybrid cloud by driving automated installation and updates across Kubernetes deployments everywhere, all powered by Kubernetes Operators. OpenShift 4 is still built on top of Red Hat Enterprise Linux, and delivered in a new immutable form as Red Hat Enterprise Linux CoreOS.
OpenShift 4 also brings a number of new developer services and capabilities needed to build cloud-native applications, to deploy them consistently across any supported on-premises, private, or public cloud infrastructure.
Red Hat OpenShift 4 is Kubernetes for the Enterprise, designed to power businesses’ digital transformation, and to unite development teams on a single platform.

What are the advantages of migrating to OpenShift 4

OpenShift 3 will only be supported until 2021, so besides the need to migrate to the new version, we also think that OpenShift 4 brings many advantages for both operators and users.
The level of maturity of operators leaves little to be desired. For the operation of a cluster, updates are much faster and at the same time, easier to handle and more stable. This also simplifies operations, as operators can react to changes and correct errors if needed. Operators are a new concept also for the operation of applications for users of OpenShift.
The switch from Docker to Buildah for container builds now allows to build container images in a more secure way. This is a welcome innovation for all multitenant clusters, such as public platform providers and corporate clusters with multiple users. With the introduction of the OpenShift Service Mesh, developers in particular will gain new insights and new possibilities to visualize, secure and optimize the communication of their applications.
OpenShift 4 represents a significant change in the way that OpenShift Container Platform clusters are deployed, managed, and developed upon. OpenShift 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. They 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.
The advantages of OpenShift 4 include:

  • 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.
  • Red Hat Serverless: enables an application to consume only the compute resources necessary, scaling up or down automatically depending on usage. This removes the overhead of server provisioning and maintenance from the developer, letting them focus on application development instead.
  • Red Hat Service Mesh: controls how different parts of an application share data with one another through a built-in dedicated infrastructure layer. This visible infrastructure layer can track different parts of an app and their interactions, to optimize communications and to avoid downtime as it grows.
  • 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.

OpenShift’s goal is to help developers to innovate more rapidly, to address the needs of the business quicker. Cloud native application development brings new challenges. As developers adopt microservice architectures, managing the communication between each service, securing those services and getting better service to service traceability to debug issues is an absolute necessity. These are the challenges that the Istio open source project seeks to address.
The OpenShift 4 Service Mesh takes Istio and combines it with other key projects, like Jaeger for tracing and Kiali for visualization, to provide better manageability and traceability to microservices deployments. Developers can focus on building the business logic, letting the service mesh manage how each microservice communicates based on policies they define. They can also leverage the tracing and visualization capabilities to debug issues when they occur.
Development approaches haven’t stopped evolving, and serverless is yet another way developers are looking to build applications, by leveraging function as a service based offerings. The Serverless model enables scaling down to zero, so as to only consume compute resources when functions execute. This can be an effective way to control operational costs, particularly in the public cloud. FaaS offerings were first pioneered by public cloud providers like AWS, but have the potential to lock your applications into a single cloud environment. This is why Red Hat is working to bring these capabilities to a hybrid cloud environment via Knative.
Red Hat is an active member of the Knative open source project, collaborating with the Kubernetes community to drive upstream development that enables hybrid serverless capabilities. Using the Knative framework enabled in OpenShift, users can extend Kubernetes to build, deploy and manage serverless applications, supporting containerized and serverless deployments from a single Kubernetes control plane.

Who is OpenShift 4 for?

Almost a year after the initial release of OpenShift 4, we believe that OpenShift Container Platform 4 is ready for productive workloads.
If you are currently running OpenShift 3, you have to evaluate and plan migrating to OpenShift 4.
What are your options?

  • Do you want to run and operate OpenShift yourself?
    • This way you “keep full control” and you decide on every detail with all the implications
    • Do you have enough staff with the needed know-how to run OpenShift operations yourself 24/7? This might mean that you have to re-train your staff and also re-engineer all operations tools.
      • You might need to hire new people or train your existing staff.
      • External consultants might be needed for specific tasks such as the setup or migration part.
  • Or do you want to work with a partner who takes care of your OpenShift installation and ensure 24/7 operations?
    • Work with a hyperscaler like AWS/Azure/Google Cloud etc.:
      • You are super flexible, you can spin up your own cluster and the additional tools you need and you can do everything yourself “at a fingertip”
      • But you are also bound to one platform and you have to ensure the actual 24/7 management and operations
    • Work with a specialized partner like VSHN / APPUiO:
      • You can be sure that you have the latest OpenShift know-how and enough people who take care of your operations, both on premises or in any cloud of your choice.
      • A certified, Swiss based Red Hat partner who knows how to run OpenShift even in the most sensitive areas and industries such as banking & finance with a focus on the business-relevant application, not the “generic platform”
      • You get Managed OpenShift, 24/7 operations, additional Managed Services for a recurring monthly fee, at the end you save time & money so that your people can focus on developing your product and / or services.

At the end, it’s not a question of if, but when to migrate to OpenShift 4.

How to migrate from OpenShift 3 to OpenShift 4

There is no planned update path from OpenShift 3 to 4. Red Hat provides migration tools, however, that can migrate not only the Kubernetes resources, but also the data from persistent volumes, where S3 Storage is used as a cache. The migration tool supports migrations from version 3 to 4 as well as migrations between different OpenShift 4 clusters.
According to the website, 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.

To successfully transition from OpenShift Container Platform 3 to OpenShift Container Platform 4, it is important that you review the following information:

  • Planning your transition: Learn about the differences between OpenShift Container Platform versions 3 and 4. Prior to transitioning, be sure that you have reviewed and prepared for storage, networking, logging, security, and monitoring considerations.
  • Performing your migration: Learn about and use the tools to perform your migration:
    • Control Plane Migration Assistance Tool (CPMA): the Control Plane Migration Assistance tool helps you configure the new cluster OpenShift 4 cluster that will be the destination for the applications that are being migrated from your existing OpenShift 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 OpenShift 3 to a destination cluster running the latest OpenShift. It also can migrate applications between OpenShift 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.

If you need detailed instructions about your OpenShift migration, head over to this page to learn more about the migration process and how to utilize the migration tooling. And of course, if you need help with your migration, we will be very happy to help you.


VSHN is a Red Hat Advanced CCSP partner and we offer Managed OpenShift since 2016 through our brand APPUiO, both in the cloud of your choice or on premises. In 2020, we are operating OpenShift clusters for 350 customers and partners in 16 clouds around the globe.
If you want to learn how we helped acrevis Bank in Switzerland with the move and how we operate OpenShift for them, check out our Success Story.

APPUiO OpenShift 4 Fact Sheet

Our APPUiO OpenShift Fact Sheet explains the benefits of OpenShift 4 in an easy to read 2-pager.

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Markus Speth

Markus is VSHN's CEO and one of the General Managers.

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