Example of adding a customized version of a Red Hat provided script.
This example will place a modified copy of java-default-options into a container derived from imagestream redhat-openjdk18-openshift:1.2 resolving the issue reported at CLOUD-2286 in a local container build. The resulting container can then be used as a modified version of registry.access.redhat.com/redhat-openjdk-18/openjdk18-openshift:1.2.
By default this example names the modified container as java-s2i-gc. You will likely want to set this to your preference and then change the buildconfig, imagestream and template accordingly.
Files in this repository:
- Dockerfile - Used to copy the modified script into a container
- buildconfig.yml - Used to define a build for a modified container
- imagestream.yml - Used to create the example imagestream
- java-default-options - the modified script we are replacing
- openjdk18-web-basic-s2i-modified.json - template to test an application pod built using the modified container
Steps for incorporating this change into your own container based on registry.access.redhat.com/redhat-openjdk-18/openjdk18-openshift:1.2:
- Save the buildconfig and imagestream and make any changes to the files that you wish.
- Create the buildconfig and imagestream in your Openshift project.
oc create -f buildconfig.yml
oc create -f imagestream.yml
- Run the build. This will create a version of registry.access.redhat.com/redhat-openjdk-18/openjdk18-openshift:1.2 that contains the modified java-default-options script. This container will be named java-s2i-gc by default.
oc start-build java-s2i-gc
- Now use the resulting output container, imagestream or imagestreamtag as the input for your Java application. The example name is java-s2i-gc. Modify this to your liking.
- Test the newly built container by creating an application pod and setting a different garbage collector. The template sets
GC_COLLECTOR=UseG1GC.
oc new-app -f openjdk18-web-basic-s2i-modified.json
Your application container will include the modified java-default-options file and will allow you to use the GC_COLLECTOR environment variable at deploy time to configure the garbage collector of your choice.
Valid values for GC_COLLECTOR are:
- UseSerialGC
- UseConcMarkSweepGC
- UseG1GC
Where UseParallelGC will be selected as a default if GC_COLLECTOR is not set.