Difficulty: beginner
Estimated Time: 60 minutes

Goal

Explore OpenShift version 4.2.

Concepts

  • OpenShift Web Console *oc command line tool
  • OpenShift Projects and Applications
  • Your applications on OpenShift

Use case

You control an OpenShift cluster for one hour. You can deploy your own container image, or set up a pipeline to build your application from source, then monitor it with Prometheus as it runs. Use an Operator to deploy and manage a database backend for your web app.

This OpenShift cluster will self-destruct in one hour.

Thank you for trying the playground. For individual exercises on using OpenShift, see the home page of our OpenShift interactive learning portal

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Playground (OpenShift 4.2)

OpenShift Playground

Before you get started we recommend reading the following tips. They explain a bit about how the playground environment is setup and what access you have.

Logging in to the Cluster via Dashboard

Click the Console tab to open the dashboard.

You will then able able to login with admin permissions with:

  • Username: admin
  • Password: admin

Or as a standard user with:

  • Username: developer
  • Password: developer

Logging in to the Cluster via CLI

When the OpenShift playground is created you will be logged in initially as a cluster admin (oc whoami) on the command line. This will allow you to perform operations which would normally be performed by a cluster admin.

Before creating any applications, it is recommended you login as a distinct user. This will be required if you want to log in to the web console and use it.

To login to the OpenShift cluster from the Terminal run:

oc login -u developer -p developer

This will log you in using the credentials:

  • Username: developer
  • Password: developer

Use the same credentials to log into the web console.

In order that you can still run commands from the command line as a cluster admin, the sudoer role has been enabled for the developer account. To execute a command as a cluster admin use the --as system:admin option to the command. For example:

oc get projects --as system:admin

Creating your own Project

To create a new project called myproject run the command:

oc new-project myproject

You could instead create the project from the web console. If you do this, to change to the project from the command line run the command:

oc project myproject

Persistent Volume Claims

Persistent volumes have been pre-created in the playground environment. These will be used if you make persistent volume claims for an application. The volume sizes are defined as 100Gi each, however you are limited by how much disk space the host running the OpenShift environment has, which is much less.

To view the list of available persistent volumes you can run:

oc get pv --as system:admin

Builder Images and Templates

The playground environment is pre-loaded with Source-to-Image (S2I) builders for Java (Wildfly), Javascript (Node.JS), Perl, PHP, Python and Ruby. Templates are also available for MariaDB, MongoDB, MySQL, PostgreSQL and Redis.

You can see the list of what is available, and what versions, under Add to Project in the web console, or by running from the command line:

oc new-app -L

Running Images as a Defined User

By default OpenShift prohibits images from running as the root user or as a specified user. Instead, each project is assigned its own unique range of user IDs that application images have to run as.

If you attempt to run an arbitrary image from an external image registry such a Docker Hub, which is not built to best practices, or requires that it be run as root, it may not work as a result.

In order to run such an image, you will need to grant additional privileges to the project you create to allow it to run an application image as any user ID. This can be done by running the command:

oc adm policy add-scc-to-user anyuid -z default -n myproject --as system:admin

Terminal
Console