Badly worded perhaps.
In some cases you don't have the ability to modify an existing image with the application in it, plus you may not want to create a new custom image as a layer on top. In those cases, if all you need to do is some minor tweaks to config prior to the application starting in the container you can use the configmap trick as described. It will work so long as the config files you need to change can be modified as the user the container is run as.
So you can do:
oc create configmap blog-run-script --from-file=run
oc set volume dc/blog --add --type=configmap \
oc patch dc/blog --type=json --patch \
So the 'run' script makes the changes and then executes original command to start the application in the container.
This doesn't make sense to me:
> 3. If don't want to create a new custom image.
If you wanna run your application in a container you have to create a custom image with the application. There's no way around, because container images are immutable. You can only choose how you will build your custom image. This is the way containers are supposed to work, with or without OpenShift.
s, Fernando Lozano