By default displaying events in Openshift 4 can sometimes create confusion, so we need to order them by using timestamp. This is the command to do it,
$ oc get events --sort-by='{.lastTimestamp}'
Just recently got an unique error, this happens when my application is pulling an image within a different Openshift namespace. In this example, im creating my application in “xyz-project” and try to pull image from “abc-project”. Here’s the complete error detail,
Failed to pull image "image-registry.openshift-image-registry.svc:5000/abc-project/image01@sha256:xxxxxxxxxxxx": rpc error: code = Unknown desc = Error reading manifest sha256:xxxxxxxxxxxx in image-registry.openshift-image-registry.svc:5000/abc-project/image01: unauthorized: authentication required
Solution for this is quite easy, actually we need to give a specific access right in order for “xyz-project” to be able to pull image from “abc-project”.
oc policy add-role-to-user system:image-puller system:serviceaccount:xyz-project:default -n abc-project
Hope it helps.
There are times where we want to display list of DC within one Namespace, and want to see what are the images involved within it. We can do that easily by using a simple OC command like below,
oc get dc -n <namespace> --no-headers -o template \
--template='{{range.items}}{{.metadata.namespace}}{{"/"}}{{.metadata.name}}{{" - "}}
{{(index .spec.template.spec.containers 0).image}}{{"\n"}}{{end}}'
Sometimes we got some pods stuck in our namespace and unable to be deleted within a specific timeframe so we need to delete them forcefully, but sometimes it becomes problematic when we have like hundreds of them. Well deleting all of them is actually quite easy, all i have to do is run below command.
oc delete pod -n youropenshiftprojectname --grace-period=0 --force --all
This is snippet code for adding a specific nodeselector to a rc (ReplicationConfig)
oc patch rc simple-helloworld -p '{"spec": {"template": {"spec": {"nodeSelector": {"infra": "my-infra-node"}}}}}' -n dev
The same code should work for other type, such as Deployment, or DeploymentConfig.