Collecting RHOCP must-gather in a Disconnected/Air-Gapp Environment.

Environment

• Red Hat OpenShift Container Platform (RHOCP)
  • 4

Issue

• How to collect properly a must-gather in RHCOP in a Disconnected/Air-Gapp Environment.
• When running oc adm must-gather in a disconnected environment, the command fails with ErrImagePull.

Resolution

1. Mirror image quay.io/openshift/origin-must-gather:latest to the disconnected registry. It can be performed from a bastion or a node with access to the mirrored registry server and also access to the appropriate permissions:

   a. Pull the image with Podman(Docker can be used as well):

   # podman pull quay.io/openshift/origin-must-gather:latest
   

   b. Get the image ID:

   # podman images origin-must-gather -q
   138613a63e4f
   

   c. Save the image to a tar file:

   # podman save 138613a63e4f -o mg.tar
   

   d. Load the image to the disconnected environment bastion:

   # podman load < mg.tar
   

   e. Push the image to the disconnected registry:

   # podman tag 138613a63e4f `$FQDN_Registry`/`$IMAGE_NAME`:`$IMAGE_TAG`
   # podman push `$FQDN_Registry`/`$IMAGE_NAME`:`$IMAGE_TAG`
   

2. Run must-gather in the disconnected environment:

   # oc adm must-gather --image=`$FQDN_Registry`/`$IMAGE_NAME`:`$IMAGE_TAG`
   

Diagnostic Steps

Running oc adm must-gather returns an error similar to the following:

# oc adm must-gather
[must-gather      ] OUT unable to resolve the imagestream tag openshift/must-gather:latest
[must-gather      ] OUT 
[must-gather      ] OUT Using must-gather plugin-in image: quay.io/openshift/origin-must-gather:latest
[must-gather      ] OUT namespace/openshift-must-gather-rsfkg created
[must-gather      ] OUT clusterrolebinding.rbac.authorization.k8s.io/must-gather-6zq2w created
[must-gather      ] OUT pod for plug-in image quay.io/openshift/origin-must-gather:latest created
[must-gather-qg74c] OUT gather did not start: unable to pull image: **ErrImagePull**: rpc error: code = Unknown desc = pinging docker registry returned: Get https://quay.io/v2/: dial tcp: lookup quay.io on 10.x.x.192:53: no such host

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