Chapter 7. Image configuration resources

Procedure

1. Edit the image.config.openshift.io/cluster custom resource:

   $ oc edit image.config.openshift.io/cluster

   The following is an example image.config.openshift.io/cluster resource:

   apiVersion: config.openshift.io/v1
   kind: Image
   metadata:
     annotations:
       release.openshift.io/create-only: "true"
     creationTimestamp: "2019-05-17T13:44:26Z"
     generation: 1
     name: cluster
     resourceVersion: "8302"
     selfLink: /apis/config.openshift.io/v1/images/cluster
     uid: e34555da-78a9-11e9-b92b-06d6c7da38dc
   spec:
     allowedRegistriesForImport:
       - domainName: quay.io
         insecure: false
     additionalTrustedCA:
       name: myconfigmap
     registrySources:
       insecureRegistries:1
       - insecure.com
       blockedRegistries:2
       - untrusted.com
       allowedRegistries:
       - quay.io 3
   status:
     internalRegistryHostname: image-registry.openshift-image-registry.svc:5000

   1

   Specify an insecure registry.

   2

   Specify registries that should be blacklisted for image pull and push actions. All other registries are allowed. Either blockedRegistries or allowedRegistries can be set, but not both.

   3

   Specify registries that should be permitted for image pull and push actions. All other registries are denied. Either blockedRegistries or allowedRegistries can be set, but not both.

   The Machine Config Operator (MCO) watches the image.config.openshift.io/cluster for any changes to registries and reboots the nodes when it detects changes. Changes to the registries appear in the /host/etc/containers/registries.conf file on each node.

   cat /host/etc/containers/registries.conf
   [registries]
     [registries.search]
       registries = ["registry.access.redhat.com", "docker.io"]
     [registries.insecure]
       registries = ["insecure.com"]
     [registries.block]
       registries = ["untrusted.com"]

Procedure

1. Configure mirrored repositories. To do that, you can either:

   • Set up a mirrored repository with Red Hat Quay, as described in Red Hat Quay Repository Mirroring. Using Red Hat Quay allows you to copy images from one repository to another and also automatically sync those repositories repeatedly over time.

   • Use a tool such as skopeo to copy images manually from the source directory to the mirrored repository.

     For example, after installing the skopeo RPM package on a Red Hat Enterprise Linux (RHEL 7 or RHEL 8) system, use the skopeo command as shown in this example:

     $ skopeo copy \
        docker://registry.access.redhat.com/ubi8/ubi-minimal@sha256:c505667389712dc337986e29ffcb65116879ef27629dc3ce6e1b17727c06e78f \
        docker://example.io/ubi8/ubi-minimal

     In this example, you have a container image registry that is named example.io with an image repository named example to which you want to copy the ubi8/ubi-minimal image from registry.access.redhat.com. After you create the registry, you can configure your OpenShift Container Platform cluster to redirect requests made of the source repository to the mirrored repository.

2. Log in to your OpenShift Container Platform cluster.

3. Create an ImageContentSourcePolicy file (for example, registryrepomirror.yaml), replacing the source and mirrors with those of your own registry and repository pairs and images:

   apiVersion: operator.openshift.io/v1alpha1
   kind: ImageContentSourcePolicy
   metadata:
     name: ubi8repo
   spec:
     repositoryDigestMirrors:
     - mirrors:
       - example.io/example/ubi-minimal1
       source: registry.access.redhat.com/ubi8/ubi-minimal2
     - mirrors:
       - example.com/example/ubi-minimal
       source: registry.access.redhat.com/ubi8/ubi-minimal

   1

   Indicates the name of the image registry and repository

   2

   Indicates the registry and repository containing the content that is mirrored

4. Create the new ImageContentSourcePolicy:

   $ oc create -f registryrepomirror.yaml

   After the ImageContentSourcePolicy is created, the new settings are deployed to each node and shortly start using the mirrored repository for requests to the source repository.

5. To check that the mirrored configuration worked, go to one of your nodes. For example:

   1. List your nodes:

      $ oc get node
      NAME                           STATUS                     ROLES    AGE  VERSION
      ip-10-0-137-44.ec2.internal    Ready                      worker   7m   v1.14.6+90fadebfa
      ip-10-0-138-148.ec2.internal   Ready                      master   11m  v1.14.6+90fadebfa
      ip-10-0-139-122.ec2.internal   Ready                      master   11m  v1.14.6+90fadebfa
      ip-10-0-147-35.ec2.internal    Ready,SchedulingDisabled   worker   7m   v1.14.6+90fadebfa
      ip-10-0-153-12.ec2.internal    Ready                      worker   7m   v1.14.6+90fadebfa
      ip-10-0-154-10.ec2.internal    Ready                      master   11m  v1.14.6+90fadebfa

      You can see that scheduling on each worker node is disabled as the change is being applied.

   2. Check the /etc/containers/registries.conf file to make sure the changes were made:

      $ oc debug node/ip-10-0-147-35.ec2.internal
      Starting pod/ip-10-0-147-35ec2internal-debug ...
      To use host binaries, run `chroot /host`
      
      sh-4.2# chroot /host
      sh-4.2# cat /etc/containers/registries
      unqualified-search-registries = ["registry.access.redhat.com", "docker.io"]
      [[registry]]
        location = "registry.access.redhat.com/ubi8/"
        insecure = false
        blocked = false
        mirror-by-digest-only = true
        prefix = ""
      
        [[registry.mirror]]
          location = "example.io/example/ubi8-minimal"
          insecure = false
      
        [[registry.mirror]]
          location = "example.com/example/ubi8-minimal"
          insecure = false

   3. Pull an image to the node from the source and check if it is actually resolved by the mirror.

      sh-4.2# podman pull --log-level=debug registry.access.redhat.com/ubi8/ubi-minimal