Over the past year, Kubernetes has emerged as the industry standard for container platforms. There are now several platforms based on Kubernetes that are offered with their own interface and preconfigured services as well as additional features. For example, the container platform dubbed “Openshift” by Red Hat is being used more and more frequently.
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Why install OpenShift offline?
In many companies, development and test environments are encapsulated in their own networks and thus secured. This means that access to and from the Internet is not possible. Even the standard installation of Openshift is somewhat complex. With the requirement to set up the environment offline, the complexity increases significantly.
We’ve tried it out and show you what you need to bear in mind when installing offline. We used Openshift with the corresponding Ansible installer and our tool
What is OpenShift?
Openshift is a container platform from Red Hat, based on Kubernetes.
OpenShift Origin and OpenShift Enterprise
As is usual with Red Hat, there is both an enterprise version with a subscription model (Openshift Enterprise) and an open source version (Openshift Origin).
New features will be integrated into Openshift Origin and included in the Enterprise version as soon as they are stable. In addition to the usual features of a container platform such as multi-tenancy, high availability, orchestration tools and integrated services for logging and monitoring, Openshift’s special feature is a collection of developer tools.
Developer functions and source-to-image builds
These range from an integrated, containerized Jenkins to webhooks for git repositories and Openshift’s source-to-image builds (S2I). With S2I, developers can give their code in a git repository directly to Openshift. They can use the corresponding development framework for this. If they do not specify this, Openshift decides which framework to use based on the file extensions.
Openshift then starts a base image with the corresponding framework. The next step is to clone the Git directory, start the application and save the resulting container image in the integrated Openshift registry.
orcharhino as a mirror for repositories and container images
The second tool used is
Lifecycle environments and content views
With the corresponding lifecycle environments and content views, the version statuses can be frozen and fixed. This provides stable package versions for productive operation. The required servers can be set up directly via appropriately connected hypervisors. Baremetal solutions are also possible. All servers can then be prepared directly for the Openshift installation using the integrated configuration management tools.
Requirements for the offline installation of OpenShift
For an offline installation, it must be ensured that all repositories and packages are available. Via
Provide repositories, packages and container images
In addition to the packages, the container images must also be synchronized. These are necessary if Openshift is to be installed in the containerized version. This is also necessary for the corresponding services that are to run in Openshift after installation.
OpenShift services for metrics, logs, registry and routing
These services include the provision of metrics, management of logs, a registry and the HAProxy for routing.
Synchronize container images with orcharhino
When synchronizing container images with orcharhino, the repo structure is changed. This changes the naming of the images.
From:
registry.access.redhat.com/openshift3/ose-haproxy-router:v3.7.46
is indicated by orcharhino:
orcharhino.atix.demo:5000/ATIX-production-openshift_content-container_images-ose-haproxy-router:v3.7.46
according to the following scheme:
:5000/----: |
Consider image names in the Ansible inventory
The sources used for the images and their modified repo structure must now be taken into account in the Ansible inventory for the offline installation. Openshift can then be set up in an environment without direct internet access.
Use orcharhino as registry for OpenShift
This requires the use of
openshift_docker_additional_registries=orcharhino.atix.demo:5000oreg_url=ATIX-production-openshift_content-container_images-ose-${component}:${version}
Operating OpenShift in complex offline environments
Dabei ist es möglich, OpenShift über mehrere Netzwerke aufzuspannen. Beispielsweise können Test- und Entwicklungsumgebung getrennt sein, aber mit den gleichen Master-Servern verwaltet werden. Analog dazu können neue Umgebungen in eine bestehende Offline-Umgebung aufgenommen und Upgrades von bestehenden Installationen durchgeführt werden.
The more complex the requirements, the more attention needs to be paid. The basic features are shown here – further details depend heavily on the environment and requirements in which the container platform is set up.
Support for the OpenShift offline installation
If you have any questions about the blog post or if you need support with the installation of a complex Openshift environment, you can contact us at any time!
