Lab: Openshift S2I and Templates
Overview
S2I is a tool deployed in OpenShift that provides a repeatable method to generate application images from source/binary code. Templates provide a parameterized set of objects that can be processed by OpenShift.
In this lab you'll use these capabilities to deploy a small legacy Java EE app to OpenShift in a multi-user OpenShift environment
Step 1: Logon into the OpenShift Web Console and to the OpenShift CLI
Follow the setup steps to gain access to the OpenShift Web Console And CLI
Step 2: Clone the WebSphere Liberty S2I image source, create a Docker image, and push it to the OpenShift internal registry
2.1 Clone the the WebSphere Liberty S2I image source by issuing the following commands in the terminal window you just used to login via the CLI
2.2 Get the hostname of your OpenShift internal registry so you can push images to it
2.4 Build the S2I Liberty image and tag it appropriately for the internal registry
2.5 Login to the internal registry
2.6 Push the S2I Liberty image to the internal registry
Step 3: Install MariaDB from the OpenShift template catalog
3.1 In your Web console browser tab select the Developer role at the top left and make sure the default project is selected. Next, click Add on the lefthand menu.
3.2 Click on the Database tile
3.4 Click on MariaDB (Ephemeral)
3.5 Click Instantiate Template
3.6 Enter the following values for the fields indicated below (leave remaining values at their default values)
Field name | Value |
MariaDB Connection Username |
|
MariaDB Connection Password |
|
MariaDB Database Name |
|
When you're done the dialog should look like the following:
3.7 Click Create
3.8 Wait until the Status changes to Ready before continuing
Step 4: Clone the Github repo that contains the code for the Plants by WebSphere app
4.1 From your terminal go back to your home directory
4.2 From the client terminal window clone the Git repo with the following commands
Step 5: Install the Plants by WebSphere Liberty app using a template that utilizes S2I to build the app image
5.1 Add the Plants by WebSphere Liberty app template to your OpenShift cluster
5.2 In your Web console browser click on + Add (top left)
5.3 Click the From Catalog tile
5.4 Select the Other category and then click on the Plants by WebSphere on Liberty tile
5.5 Click Instantiate Template
5.6 Click Create
5.7 To see the progress of the build and subsequent deployment select the Administrator role, then select Workloads and then Pods. The builder pod should be running (Note: that name of the pod will have build as a suffix)
5.8 After a few minutes the build pod will terminate and the pod with the Plants by Websphere app will appear. Wait for that pod to show Ready before continuing. (Note: the name of the pod will not have build as a suffix).
5.9 In the navigation area on the left click Networking and then Routes. Click on the link in the Location column to launch the Plants By WebSphere app.
Step 6: Test the Plants by WebSphere app
6.1 From the Plants by WebSphere app UI, click on the HELP link
6.2. Click on Reset database to populate the MariaDB database with data
6.3. Verify that browsing different sections of the online catalog shows product descriptions and images.
Summary
With even small simple apps requiring multiple OpenShift objects, templates greatly simplify the process of distributing OpenShift apps. S2I allows you to reuse the same builder image for apps on the same app server, avoiding the effort of having to create unique images for each app.
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