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Chapter 9. Image configuration resources (Classic)

You can configure an image registry to store and serve container images.

9.1. Image controller configuration parameters
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You can configure certain parameters that handle images cluster-wide in the spec of the image.config.openshift.io/cluster resource.

Note

The following non-configurable parameters are not listed in the table:

  • DisableScheduledImport
  • MaxImagesBulkImportedPerRepository
  • MaxScheduledImportsPerMinute
  • ScheduledImageImportMinimumIntervalSeconds
  • InternalRegistryHostname
Expand
Table 9.1. Image controller configuration parameters
Field nameDescription

kind.Image

Holds cluster-wide information about how to handle images. The canonical, and only valid name for this CR is cluster.

allowedRegistriesForImport

Limits the container image registries from which normal users can import images. Set this list to the registries that you trust to contain valid images, and that you want applications to be able to import from. Users with permission to create images or ImageStreamMappings from the API are not affected by this policy. Typically only cluster administrators have the appropriate permissions.

Every element of this list contains a location of the registry specified by the registry domain name.

domainName: Specifies a domain name for the registry. If the registry uses a non-standard 80 or 443 port, the port should be included in the domain name as well.

insecure: Insecure indicates whether the registry is secure or insecure. By default, if not otherwise specified, the registry is assumed to be secure.

additionalTrustedCA

A reference to a config map containing additional CAs that should be trusted during image stream import, pod image pull, openshift-image-registry pullthrough, and builds.

The namespace for this config map is openshift-config. The format of the config map is to use the registry hostname as the key, and the PEM-encoded certificate as the value, for each additional registry CA to trust.

externalRegistryHostnames

Provides the hostnames for the default external image registry. The external hostname should be set only when the image registry is exposed externally. The first value is used in publicDockerImageRepository field in image streams. The value must be in hostname[:port] format.

registrySources

Contains configuration that determines how the container runtime should treat individual registries when accessing images for builds and pods. For example, whether or not to allow insecure access. It does not contain configuration for the internal cluster registry.

insecureRegistries: Registries that do not have a valid TLS certificate or only support HTTP connections. To specify all subdomains, add the asterisk (*) wildcard character as a prefix to the domain name. For example, *.example.com. You can specify an individual repository within a registry. For example: reg1.io/myrepo/myapp:latest.

blockedRegistries: Registries for which image pull and push actions are denied. To specify all subdomains, add the asterisk (*) wildcard character as a prefix to the domain name. For example, *.example.com. You can specify an individual repository within a registry. For example: reg1.io/myrepo/myapp:latest. All other registries are allowed.

allowedRegistries: Registries for which image pull and push actions are allowed. To specify all subdomains, add the asterisk (*) wildcard character as a prefix to the domain name. For example, *.example.com. You can specify an individual repository within a registry. For example: reg1.io/myrepo/myapp:latest. All other registries are blocked.

containerRuntimeSearchRegistries: Registries for which image pull and push actions are allowed using image short names. All other registries are blocked.

You can set either blockedRegistries or allowedRegistries, but not both.

imageStreamImportMode

Controls the import mode behavior of image streams.

You must enable the TechPreviewNoUpgrade feature set in the FeatureGate custom resource (CR) to enable the imageStreamImportMode feature. For more information about feature gates, see "Understanding feature gates".

You can set the imageStreamImportMode field to either of the following values:

  • Legacy: Indicates that the legacy behavior must be used. The legacy behavior discards the manifest list and imports a single sub-manifest. In this case, the platform is chosen in the following order of priority:

    1. Tag annotations: Determining the platform by using the platform-specific annotations in the image tags.
    2. Control plane architecture or the operating system: Selecting the platform based on the architecture or the operating system of the control plane.
    3. linux/amd64: If no platform is selected by the preceeding methods, the linux/amd64 platform is selected.
    4. The first manifest in the list is selected.
  • PreserveOriginal: Indicates that the original manifest is preserved. The manifest list and its sub-manifests are imported.

If you specify a value for this field, the value is applied to the newly created image stream tags that do not already have this value manually set.

If you do not configure this field, the behavior is decided based on the payload type advertised by the ClusterVersion status. In this case, the platform is chosen as follows:

  • The single architecture payload implies that the Legacy mode is applicable.
  • The multi payload implies that the PreserveOriginal mode is applicable.

For information about importing manifest lists, see "Working with manifest lists".

Important

imageStreamImportMode is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see the following link:

Warning

When you define the allowedRegistries parameter, all registries, including registry.redhat.io, quay.io, and the default OpenShift image registry, are blocked unless explicitly listed. You must add all of the registries that your payload images require to the allowedRegistries list. For example, list registry.redhat.io, quay.io, and the internalRegistryHostname registries. For disconnected clusters, you must also add your mirror registries. Otherwise, you risk pod failure.

The status field of the image.config.openshift.io/cluster resource holds observed values from the cluster.

Expand
Table 9.2. Image controller status field parameters
ParameterDescription

internalRegistryHostname

Set by the Image Registry Operator, which controls the internalRegistryHostname. It sets the hostname for the default OpenShift image registry. The value must be in hostname[:port] format. For backward compatibility, you can still use the OPENSHIFT_DEFAULT_REGISTRY environment variable, but this setting overrides the environment variable.

externalRegistryHostnames

Set by the Image Registry Operator, provides the external hostnames for the image registry when it is exposed externally. The first value is used in publicDockerImageRepository field in image streams. The values must be in hostname[:port] format.

9.2. Machine Config Operator behavior and registry changes
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The Machine Config Operator (MCO) watches the image.config.openshift.io/cluster custom resource (CR) for any changes to registries and takes specific steps when the registry changes.

When changes to the registry are applied to the image.config.openshift.io/cluster CR, the MCO performs the following sequential actions:

  1. Cordons the node; certain parameters result in drained nodes, and others do not
  2. Applies changes by restarting CRI-O

  3. Uncordons the node

    Note

    The MCO does not restart nodes when it detects changes. During this period, you might experience service unavailability.

9.2.1. When allowing and blocking registry sources
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The MCO watches the image.config.openshift.io/cluster resource for any changes to the registries. When the MCO detects a change, it triggers a rollout on nodes in machine config pool (MCP). The allowed registries list is used to update the image signature policy in the /etc/containers/policy.json file on each node. Changes to the /etc/containers/policy.json file do not require the node to drain.

9.2.2. When using the containerRuntimeSearchRegistries parameter
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After the nodes return to the Ready state, if the containerRuntimeSearchRegistries parameter is added, the MCO creates a file in the /etc/containers/registries.conf.d directory on each node with the listed registries. The file overrides the default list of unqualified search registries in the /etc/containers/registries.conf file. There is no way to fall back to the default list of unqualified search registries.

Important

The containerRuntimeSearchRegistries parameter works only with the Podman and CRI-O container engines. The registries in the list can be used only in pod specs, not in builds and image streams.

9.3. Configuring image registry settings
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You can configure image registry settings by editing the image.config.openshift.io/cluster custom resource (CR).

Procedure

  1. Edit the image.config.openshift.io/cluster CR by running the following command: 

    $ oc edit image.config.openshift.io/cluster
    Copy to Clipboard Toggle word wrap

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

    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:
    allowedRegistries:
    - example.com
    - quay.io
    - registry.redhat.io
    - image-registry.openshift-image-registry.svc:5000
    - reg1.io/myrepo/myapp:latest
    insecureRegistries:
    - insecure.com
status:
  internalRegistryHostname: image-registry.openshift-image-registry.svc:5000
    Copy to Clipboard Toggle word wrap
    Note

    When you use the allowedRegistries, blockedRegistries, or insecureRegistries parameter, you can specify an individual repository within a registry. For example: reg1.io/myrepo/myapp:latest.

    Avoid insecure external registries to reduce possible security risks.

Verification

  1. To verify your changes, list your nodes by running the following command: 

    $ oc get nodes
    Copy to Clipboard Toggle word wrap

    Example output

    NAME                                         STATUS                     ROLES                  AGE   VERSION
ip-10-0-137-182.us-east-2.compute.internal   Ready,SchedulingDisabled   worker                 65m   v1.31.3
ip-10-0-139-120.us-east-2.compute.internal   Ready,SchedulingDisabled   control-plane          74m   v1.31.3
ip-10-0-176-102.us-east-2.compute.internal   Ready                      control-plane          75m   v1.31.3
ip-10-0-188-96.us-east-2.compute.internal    Ready                      worker                 65m   v1.31.3
ip-10-0-200-59.us-east-2.compute.internal    Ready                      worker                 63m   v1.31.3
ip-10-0-223-123.us-east-2.compute.internal   Ready                      control-plane          73m   v1.31.3
    Copy to Clipboard Toggle word wrap

9.3.1. Adding specific registries to an allowlist
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You can add an allowlist of registries, or an individual repository, within a registry for image pull and push actions by editing the image.config.openshift.io/cluster custom resource (CR).

OpenShift Container Platform applies the changes to this CR to all nodes in the cluster.

When pulling or pushing images, the container runtime searches the registries listed under the registrySources parameter in the image.config.openshift.io/cluster CR. If you created a list of registries under the allowedRegistries parameter, the container runtime searches only those registries. Registries not in your allowlist are blocked.

Warning

When you define the allowedRegistries parameter, all registries, including registry.redhat.io, quay.io, and the default OpenShift image registry, are blocked unless explicitly listed. You must add all of the registries that your payload images require to the allowedRegistries list. For example, list registry.redhat.io, quay.io, and the internalRegistryHostname registries. For disconnected clusters, you must also add your mirror registries. Otherwise, you risk pod failure.

Procedure

  • Edit the image.config.openshift.io/cluster custom resource by running the following command: 

    $ oc edit image.config.openshift.io/cluster
    Copy to Clipboard Toggle word wrap

    The following is an example image.config.openshift.io/cluster CR with an allowed list: 

    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:
  registrySources:
    allowedRegistries:
    - example.com
    - quay.io
    - registry.redhat.io
    - reg1.io/myrepo/myapp:latest
    - image-registry.openshift-image-registry.svc:5000
status:
  internalRegistryHostname: image-registry.openshift-image-registry.svc:5000
    Copy to Clipboard Toggle word wrap

    1. After you make your configuration updates, list your nodes by running the following command: 

      $ oc get nodes
      Copy to Clipboard Toggle word wrap

      Example output 

      NAME               STATUS   ROLES                  AGE   VERSION
<node_name>        Ready    control-plane,master   37m   v1.27.8+4fab27b
      Copy to Clipboard Toggle word wrap

    2. Enter debug mode on the node by running the following command: 

      $ oc debug node/<node_name>
      Copy to Clipboard Toggle word wrap

      Replace <node_name> with the name of your node.

    3. When prompted, enter chroot /host into the terminal: 

      sh-4.4# chroot /host
      Copy to Clipboard Toggle word wrap

Verification

  1. Check that the registries are in the policy file by running the following command: 

    sh-5.1# cat /etc/containers/policy.json | jq '.'
    Copy to Clipboard Toggle word wrap

    The following policy indicates that only images from the example.com, quay.io, and registry.redhat.io registries are accessible for image pulls and pushes:

    Example image signature policy file

    {
   "default":[
      {
         "type":"reject"
      }
   ],
   "transports":{
      "atomic":{
         "example.com":[
            {
               "type":"insecureAcceptAnything"
            }
         ],
         "image-registry.openshift-image-registry.svc:5000":[
            {
               "type":"insecureAcceptAnything"
            }
         ],
         "insecure.com":[
            {
               "type":"insecureAcceptAnything"
            }
         ],
         "quay.io":[
            {
               "type":"insecureAcceptAnything"
            }
         ],
         "reg4.io/myrepo/myapp:latest":[
            {
               "type":"insecureAcceptAnything"
            }
         ],
         "registry.redhat.io":[
            {
               "type":"insecureAcceptAnything"
            }
         ]
      },
      "docker":{
         "example.com":[
            {
               "type":"insecureAcceptAnything"
            }
         ],
         "image-registry.openshift-image-registry.svc:5000":[
            {
               "type":"insecureAcceptAnything"
            }
         ],
         "insecure.com":[
            {
               "type":"insecureAcceptAnything"
            }
         ],
         "quay.io":[
            {
               "type":"insecureAcceptAnything"
            }
         ],
         "reg4.io/myrepo/myapp:latest":[
            {
               "type":"insecureAcceptAnything"
            }
         ],
         "registry.redhat.io":[
            {
               "type":"insecureAcceptAnything"
            }
         ]
      },
      "docker-daemon":{
         "":[
            {
               "type":"insecureAcceptAnything"
            }
         ]
      }
   }
}
    Copy to Clipboard Toggle word wrap

    Note

    If your cluster uses the registrySources.insecureRegistries parameter, ensure that any insecure registries are included in the allowed list.

    For example: 

    spec:
  registrySources:
    insecureRegistries:
    - insecure.com
    allowedRegistries:
    - example.com
    - quay.io
    - registry.redhat.io
    - insecure.com
    - image-registry.openshift-image-registry.svc:5000
    Copy to Clipboard Toggle word wrap

9.3.2. Blocking specific registries
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You can block any registry, or an individual repository, within a registry by editing the image.config.openshift.io/cluster custom resource (CR).

OpenShift Container Platform applies the changes to this CR to all nodes in the cluster.

When pulling or pushing images, the container runtime searches the registries listed under the registrySources parameter in the image.config.openshift.io/cluster CR. If you created a list of registries under the blockedRegistries parameter, the container runtime does not search those registries. All other registries are allowed.

Warning

To prevent pod failure, do not add the registry.redhat.io and quay.io registries to the blockedRegistries list. Payload images within your environment require access to these registries.

Procedure

  • Edit the image.config.openshift.io/cluster custom resource by running the following command: 

    $ oc edit image.config.openshift.io/cluster
    Copy to Clipboard Toggle word wrap

    The following is an example image.config.openshift.io/cluster CR with a blocked list: 

    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:
  registrySources:
    blockedRegistries:
    - untrusted.com
    - reg1.io/myrepo/myapp:latest
status:
  internalRegistryHostname: image-registry.openshift-image-registry.svc:5000
    Copy to Clipboard Toggle word wrap

    You cannot set both the blockedRegistries and allowedRegistries parameters. You must select one or the other.

    1. Get a list of your nodes by running the following command: 

      $ oc get nodes
      Copy to Clipboard Toggle word wrap

      Example output 

      NAME                STATUS   ROLES                  AGE   VERSION
<node_name>         Ready    control-plane,master   37m   v1.27.8+4fab27b
      Copy to Clipboard Toggle word wrap

    2. Run the following command to enter debug mode on the node: 

      $ oc debug node/<node_name>
      Copy to Clipboard Toggle word wrap

      Replace <node_name> with the name of the node you want details about.

    3. When prompted, enter chroot /host into the terminal: 

      sh-4.4# chroot /host
      Copy to Clipboard Toggle word wrap

Verification

  1. Verify that the registries are in the policy file by running the following command: 

    sh-5.1# cat etc/containers/registries.conf
    Copy to Clipboard Toggle word wrap

    The following example indicates that images from the untrusted.com registry are blocked for image pulls and pushes:

    Example output

    unqualified-search-registries = ["registry.access.redhat.com", "docker.io"]

[[registry]]
  prefix = ""
  location = "untrusted.com"
  blocked = true
    Copy to Clipboard Toggle word wrap

9.3.3. Blocking a payload registry
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In a mirroring configuration, you can block upstream payload registries in a disconnected environment by using a ImageContentSourcePolicy (ICSP) object. The following example procedure demonstrates how to block the quay.io/openshift-payload payload registry.

Procedure

  1. Create the mirror configuration using an ImageContentSourcePolicy (ICSP) object to mirror the payload to a registry in your instance. The following example ICSP file mirrors the payload internal-mirror.io/openshift-payload: 

    apiVersion: operator.openshift.io/v1alpha1
kind: ImageContentSourcePolicy
metadata:
  name: my-icsp
spec:
  repositoryDigestMirrors:
  - mirrors:
    - internal-mirror.io/openshift-payload
    source: quay.io/openshift-payload
    Copy to Clipboard Toggle word wrap

  2. After the object deploys onto your nodes, verify that the mirror configuration is set by checking the /etc/containers/registries.conf custom resource (CR):

    Example output

    [[registry]]
  prefix = ""
  location = "quay.io/openshift-payload"
  mirror-by-digest-only = true

[[registry.mirror]]
  location = "internal-mirror.io/openshift-payload"
    Copy to Clipboard Toggle word wrap

  3. Use the following command to edit the image.config.openshift.io CR: 

    $ oc edit image.config.openshift.io cluster
    Copy to Clipboard Toggle word wrap

  4. To block the payload registry, add the following configuration to the image.config.openshift.io CR: 

    spec:
  registrySources:
    blockedRegistries:
     - quay.io/openshift-payload
    Copy to Clipboard Toggle word wrap

Verification

  • Verify that the upstream payload registry is blocked by checking the /etc/containers/registries.conf file on the node.

    Example /etc/containers/registries.conf file

    [[registry]]
  prefix = ""
  location = "quay.io/openshift-payload"
  blocked = true
  mirror-by-digest-only = true

[[registry.mirror]]
  location = "internal-mirror.io/openshift-payload"
    Copy to Clipboard Toggle word wrap

9.3.4. Allowing insecure registries
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You can add insecure registries, or an individual repository, within a registry by editing the image.config.openshift.io/cluster custom resource (CR).

OpenShift Container Platform applies the changes to this CR to all nodes in the cluster. Registries that do not use valid SSL certificates or do not require HTTPS connections are considered insecure.

Important

Avoid insecure external registries to reduce possible security risks.

+ :leveloffset: +1

Warning

When you define the allowedRegistries parameter, all registries, including registry.redhat.io, quay.io, and the default OpenShift image registry, are blocked unless explicitly listed. You must add all of the registries that your payload images require to the allowedRegistries list. For example, list registry.redhat.io, quay.io, and the internalRegistryHostname registries. For disconnected clusters, you must also add your mirror registries. Otherwise, you risk pod failure.

Procedure

  • Edit the image.config.openshift.io/cluster custom resource (CR) by running the following command: 

    $ oc edit image.config.openshift.io/cluster
    Copy to Clipboard Toggle word wrap

    The following is an example image.config.openshift.io/cluster CR with an insecure registries list: 

    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:
  registrySources:
    insecureRegistries:
    - insecure.com
    - reg4.io/myrepo/myapp:latest
    allowedRegistries:
    - example.com
    - quay.io
    - registry.redhat.io
    - insecure.com
    - reg4.io/myrepo/myapp:latest
    - image-registry.openshift-image-registry.svc:5000
status:
  internalRegistryHostname: image-registry.openshift-image-registry.svc:5000
    Copy to Clipboard Toggle word wrap

Verification

  • Check that the registries are added to the policy file by running the following command on a node: 

    $ cat /etc/containers/registries.conf
    Copy to Clipboard Toggle word wrap

    The following example indicates that images from the insecure.com registry is insecure and are allowed for image pulls and pushes.

    Example output

    unqualified-search-registries = ["registry.access.redhat.com", "docker.io"]

[[registry]]
  prefix = ""
  location = "insecure.com"
  insecure = true
    Copy to Clipboard Toggle word wrap

9.4. About adding registries that allow image short names
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With an image short name, you can search for images without including the fully qualified domain name in the pull spec parameter.

For example, you could use rhel7/etcd instead of registry.access.redhat.com/rhe7/etcd. You can add registries to search for an image short name by editing the image.config.openshift.io/cluster custom resource (CR).

You might use short names in situations where using the full path is not practical. For example, if your cluster references multiple internal registries whose DNS changes often, you would need to update the fully qualified domain names in your pull specs with each change. In this case, using an image short name might be beneficial.

When pulling or pushing images, the container runtime searches the registries listed under the registrySources parameter in the image.config.openshift.io/cluster CR. If you created a list of registries under the containerRuntimeSearchRegistries parameter, when pulling an image with a short name, the container runtime searches those registries.

9.4.1. When not to use image short names
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Using image short names with public registries is strongly discouraged because the image might not deploy if the public registry requires authentication. Use fully-qualified image names with public registries.

Red Hat internal or private registries typically support the use of image short names.

You cannot list multiple public registries under the containerRuntimeSearchRegistries parameter if each public registry requires different credentials and a cluster does not list the public registry in the global pull secret.

For a public registry that requires authentication, you can use an image short name only if the registry has its credentials stored in the global pull secret.

Warning

If you list public registries under the containerRuntimeSearchRegistries parameter (including the registry.redhat.io, docker.io, and quay.io registries), you expose your credentials to all the registries on the list, and you risk network and registry attacks. Because you can only have one pull secret for pulling images, as defined by the global pull secret, that secret is used to authenticate against every registry in that list. Therefore, if you include public registries in the list, you introduce a security risk.

9.4.2. Adding registries that allow image short names
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You can add registries to search for an image short name by editing the image.config.openshift.io/cluster custom resource (CR). OpenShift Container Platform applies the changes to this CR to all nodes in the cluster.

Warning

When you define the allowedRegistries parameter, all registries, including registry.redhat.io, quay.io, and the default OpenShift image registry, are blocked unless explicitly listed. You must add all of the registries that your payload images require to the allowedRegistries list. For example, list registry.redhat.io, quay.io, and the internalRegistryHostname registries. For disconnected clusters, you must also add your mirror registries. Otherwise, you risk pod failure.

Procedure

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

    $ oc edit image.config.openshift.io/cluster
    Copy to Clipboard Toggle word wrap

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

    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:
    containerRuntimeSearchRegistries:
    - reg1.io
    - reg2.io
    - reg3.io
    allowedRegistries:
    - example.com
    - quay.io
    - registry.redhat.io
    - reg1.io
    - reg2.io
    - reg3.io
    - image-registry.openshift-image-registry.svc:5000
...
status:
  internalRegistryHostname: image-registry.openshift-image-registry.svc:5000
    Copy to Clipboard Toggle word wrap

    1. Get a list of your nodes by running the following command: 

      $ oc get nodes
      Copy to Clipboard Toggle word wrap

      Example output 

      NAME                STATUS   ROLES                  AGE   VERSION
<node_name>         Ready    control-plane,master   37m   v1.27.8+4fab27b
      Copy to Clipboard Toggle word wrap

    2. Run the following command to enter debug mode on the node: 

      $ oc debug node/<node_name>
      Copy to Clipboard Toggle word wrap

    3. When prompted, enter chroot /host into the terminal: 

      sh-4.4# chroot /host
      Copy to Clipboard Toggle word wrap

Verification

  1. Verify that registries are added to the policy file by running the following command: 

    sh-5.1# cat /etc/containers/registries.conf.d/01-image-searchRegistries.conf
    Copy to Clipboard Toggle word wrap

    Example output

    unqualified-search-registries = ['reg1.io', 'reg2.io', 'reg3.io']
    Copy to Clipboard Toggle word wrap

9.4.3. Configuring additional trust stores for image registry access
Copia collegamento

You can add references to a config map that has additional certificate authorities (CAs) to be trusted during image registry access to the image.config.openshift.io/cluster custom resource (CR).

Prerequisites

  • The certificate authorities (CAs) must be PEM-encoded.

Procedure

  1. Create a config map in the openshift-config namespace, then and use the config map name in the AdditionalTrustedCA parameter of the image.config.openshift.io CR. This adds CAs that should be trusted when the cluster contacts external image registries.

    Image registry CA config map example

    apiVersion: v1
kind: ConfigMap
metadata:
  name: my-registry-ca
data:
  registry.example.com: |
    -----BEGIN CERTIFICATE-----
    ...
    -----END CERTIFICATE-----
  registry-with-port.example.com..5000: |
    -----BEGIN CERTIFICATE-----
    ...
    -----END CERTIFICATE-----
    Copy to Clipboard Toggle word wrap

    where:

    data:registry.example.com:
    An example hostname of a registry for which this CA is to be trusted.
    data:registry-with-port.example.com..5000:

    An example hostname of a registry with the port for which this CA is to be trusted. If the registry has a port, such as registry-with-port.example.com:5000, : must be replaced with ...

    The PEM certificate content is the value for each additional registry CA to trust.

  2. Optional. Configure an additional CA by running the following command: 

    $ oc create configmap registry-config --from-file=<external_registry_address>=ca.crt -n openshift-config
    Copy to Clipboard Toggle word wrap 
    $ oc edit image.config.openshift.io cluster
    Copy to Clipboard Toggle word wrap 
    spec:
  additionalTrustedCA:
    name: registry-config
    Copy to Clipboard Toggle word wrap

9.5. Understanding image registry repository mirroring
Copia collegamento

By setting up container registry repository mirroring, you can perform the following tasks:

  • Configure your OpenShift Container Platform cluster to redirect requests to pull images from a repository on a source image registry and have it resolved by a repository on a mirrored image registry.
  • Identify multiple mirrored repositories for each target repository, to make sure that if one mirror is down, another can be used.

Repository mirroring in OpenShift Container Platform includes the following attributes:

  • Image pulls are resilient to registry downtimes.
  • Clusters in disconnected environments can pull images from critical locations, such as quay.io, and have registries behind a company firewall provide the requested images.
  • A particular order of registries is tried when an image pull request is made, with the permanent registry typically being the last one tried.
  • The mirror information you enter is added to the /etc/containers/registries.conf file on every node in the OpenShift Container Platform cluster.
  • When a node makes a request for an image from the source repository, it tries each mirrored repository in turn until it finds the requested content. If all mirrors fail, the cluster tries the source repository. If successful, the image is pulled to the node.

You can set up repository mirroring in the following ways:

  • At OpenShift Container Platform installation:

    By pulling container images needed by OpenShift Container Platform and then bringing those images behind your company’s firewall, you can install OpenShift Container Platform into a data center that is in a disconnected environment.

  • After OpenShift Container Platform installation:

    If you did not configure mirroring during OpenShift Container Platform installation, you can do so postinstallation by using any of the following custom resource (CR) objects:

    • ImageDigestMirrorSet (IDMS). This object allows you to pull images from a mirrored registry by using digest specifications. The IDMS CR enables you to set a fall back policy that allows or stops continued attempts to pull from the source registry if the image pull fails.
    • ImageTagMirrorSet (ITMS). This object allows you to pull images from a mirrored registry by using image tags. The ITMS CR enables you to set a fall back policy that allows or stops continued attempts to pull from the source registry if the image pull fails.

    • ImageContentSourcePolicy (ICSP). This object allows you to pull images from a mirrored registry by using digest specifications. The ICSP CR always falls back to the source registry if the mirrors do not work.

      Important

      Using an ImageContentSourcePolicy (ICSP) object to configure repository mirroring is a deprecated feature. Deprecated functionality is still included in OpenShift Container Platform and continues to be supported. It will be removed in a future release and is not recommended for new deployments.

      If you have existing YAML files that you used to create ImageContentSourcePolicy objects, you can use the oc adm migrate icsp command to convert those files to a ImageDigestMirrorSet YAML files. For more information, see "Converting ImageContentSourcePolicy (ICSP) files for image registry repository mirroring".

Each of these custom resource objects identify the following information:

  • The source of the container image repository you want to mirror.
  • A separate entry for each mirror repository you want to offer the content

Note the following actions and how they affect node drain behavior:

  • If you create an IDMS or ICSP CR object, the MCO does not drain or reboot the node.
  • If you create an ITMS CR object, the MCO drains and reboots the node.
  • If you delete an ITMS, IDMS, or ICSP CR object, the MCO drains and reboots the node.

  • If you modify an ITMS, IDMS, or ICSP CR object, the MCO drains and reboots the node.

    Important

    • When the MCO detects any of the following changes, it applies the update without draining or rebooting the node:

      • Changes to the SSH key in the spec.config.passwd.users.sshAuthorizedKeys parameter of a machine config.
      • Changes to the global pull secret or pull secret in the openshift-config namespace.
      • Automatic rotation of the /etc/kubernetes/kubelet-ca.crt certificate authority (CA) by the Kubernetes API Server Operator.

    • When the MCO detects changes to the /etc/containers/registries.conf file, such as editing an ImageDigestMirrorSet, ImageTagMirrorSet, or ImageContentSourcePolicy object, it drains the corresponding nodes, applies the changes, and uncordons the nodes. The node drain does not happen for the following changes:

      • The addition of a registry with the pull-from-mirror = "digest-only" parameter set for each mirror.
      • The addition of a mirror with the pull-from-mirror = "digest-only" parameter set in a registry.
      • The addition of items to the unqualified-search-registries list.

For new clusters, you can use IDMS, ITMS, and ICSP CRs objects as needed. However, using IDMS and ITMS is recommended.

If you upgraded a cluster, any existing ICSP objects remain stable, and both IDMS and ICSP objects are supported. Workloads that use ICSP objects continue to function as expected. However, if you want to take advantage of the fallback policies introduced in the IDMS CRs, you can migrate current workloads to IDMS objects by using the oc adm migrate icsp command as shown in the Converting ImageContentSourcePolicy (ICSP) files for image registry repository mirroring section that follows. Migrating to IDMS objects does not require a cluster reboot.

Note

If your cluster uses an ImageDigestMirrorSet, ImageTagMirrorSet, or ImageContentSourcePolicy object to configure repository mirroring, you can use only global pull secrets for mirrored registries. You cannot add a pull secret to a project.

9.5.1. Configuring image registry repository mirroring
Copia collegamento

You can create postinstallation mirror configuration custom resources (CR) to redirect image pull requests from a source image registry to a mirrored image registry.

Prerequisites

  • Access to the cluster as a user with the cluster-admin role.

Procedure

  1. Configure mirrored repositories, by either:

    • Setting up a mirrored repository with Red Hat Quay. You can copy images from one repository to another and also automatically sync those repositories repeatedly over time by using Red Hat Quay.

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

      For example, after installing the skopeo RPM package on a {op-system-base-full system}, use the skopeo command as shown in the following example: 

      $ skopeo copy --all \
docker://registry.access.redhat.com/ubi9/ubi-minimal:latest@sha256:5cf... \
docker://example.io/example/ubi-minimal
      Copy to Clipboard Toggle word wrap

      In this example, you have a container image registry named example.io and image repository named example. You want to copy the ubi9/ubi-minimal image from registry.access.redhat.com to example.io. After you create the mirrored registry, you can configure your OpenShift Container Platform cluster to redirect requests made to the source repository to the mirrored repository.

  2. Create a postinstallation mirror configuration custom resource (CR), by using one of the following examples:

    • Create an ImageDigestMirrorSet or ImageTagMirrorSet CR, as needed, replacing the source and mirrors with your own registry and repository pairs and images: 

      apiVersion: config.openshift.io/v1
kind: ImageDigestMirrorSet
metadata:
  name: ubi9repo
spec:
  imageDigestMirrors:
  - mirrors:
    - example.io/example/ubi-minimal
    - example.com/example2/ubi-minimal
    source: registry.access.redhat.com/ubi9/ubi-minimal
    mirrorSourcePolicy: AllowContactingSource
  - mirrors:
    - mirror.example.com/redhat
    source: registry.example.com/redhat
    mirrorSourcePolicy: AllowContactingSource
  - mirrors:
    - mirror.example.com
    source: registry.example.com
    mirrorSourcePolicy: AllowContactingSource
  - mirrors:
    - mirror.example.net/image
    source: registry.example.com/example/myimage
    mirrorSourcePolicy: AllowContactingSource
  - mirrors:
    - mirror.example.net
    source: registry.example.com/example
    mirrorSourcePolicy: AllowContactingSource
  - mirrors:
    - mirror.example.net/registry-example-com
    source: registry.example.com
    mirrorSourcePolicy: AllowContactingSource
      Copy to Clipboard Toggle word wrap

    • Create an ImageContentSourcePolicy custom resource, replacing the source and mirrors with your own registry and repository pairs and images: 

      apiVersion: operator.openshift.io/v1alpha1
kind: ImageContentSourcePolicy
metadata:
  name: mirror-ocp
spec:
  repositoryDigestMirrors:
  - mirrors:
    - mirror.registry.com:443/ocp/release
    source: quay.io/openshift-release-dev/ocp-release
  - mirrors:
    - mirror.registry.com:443/ocp/release
    source: quay.io/openshift-release-dev/ocp-v4.0-art-dev
      Copy to Clipboard Toggle word wrap

      where:

      - mirror.registry.com:443/ocp/release
      Specifies the name of the mirror image registry and repository.
      source: quay.io/openshift-release-dev/ocp-release
      Specifies the online registry and repository containing the content that is mirrored.

  3. Create the new object by running the following command: 

    $ oc create -f registryrepomirror.yaml
    Copy to Clipboard Toggle word wrap

    After the object is created, the Machine Config Operator (MCO) drains the nodes for ImageTagMirrorSet objects only. The MCO does not drain the nodes for ImageDigestMirrorSet and ImageContentSourcePolicy objects.

  4. To check that the mirrored configuration settings are applied, do the following on one of the nodes.

    1. List your nodes: 

      $ oc get node
      Copy to Clipboard Toggle word wrap

      Example output

      NAME                           STATUS                     ROLES    AGE  VERSION
ip-10-0-137-44.ec2.internal    Ready                      worker   7m   v1.31.3
ip-10-0-138-148.ec2.internal   Ready                      master   11m  v1.31.3
ip-10-0-139-122.ec2.internal   Ready                      master   11m  v1.31.3
ip-10-0-147-35.ec2.internal    Ready                      worker   7m   v1.31.3
ip-10-0-153-12.ec2.internal    Ready                      worker   7m   v1.31.3
ip-10-0-154-10.ec2.internal    Ready                      master   11m  v1.31.3
      Copy to Clipboard Toggle word wrap

    2. Start the debugging process to access the node: 

      $ oc debug node/ip-10-0-147-35.ec2.internal
      Copy to Clipboard Toggle word wrap

      Example output

      Starting pod/ip-10-0-147-35ec2internal-debug ...
To use host binaries, run `chroot /host`
      Copy to Clipboard Toggle word wrap

    3. Change your root directory to /host: 

      sh-4.2# chroot /host
      Copy to Clipboard Toggle word wrap

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

      sh-4.2# cat /etc/containers/registries.conf
      Copy to Clipboard Toggle word wrap

      The following output represents a registries.conf file where postinstallation mirror configuration CRs are applied.

      Example output

      unqualified-search-registries = ["registry.access.redhat.com", "docker.io"]
short-name-mode = ""

[[registry]]
  prefix = ""
  location = "registry.access.redhat.com/ubi9/ubi-minimal"

  [[registry.mirror]]
    location = "example.io/example/ubi-minimal"
    pull-from-mirror = "digest-only"

  [[registry.mirror]]
    location = "example.com/example/ubi-minimal"
    pull-from-mirror = "digest-only"

[[registry]]
  prefix = ""
  location = "registry.example.com"

  [[registry.mirror]]
    location = "mirror.example.net/registry-example-com"
    pull-from-mirror = "digest-only"

[[registry]]
  prefix = ""
  location = "registry.example.com/example"

  [[registry.mirror]]
    location = "mirror.example.net"
    pull-from-mirror = "digest-only"

[[registry]]
  prefix = ""
  location = "registry.example.com/example/myimage"

  [[registry.mirror]]
    location = "mirror.example.net/image"
    pull-from-mirror = "digest-only"

[[registry]]
  prefix = ""
  location = "registry.example.com"

  [[registry.mirror]]
    location = "mirror.example.com"
    pull-from-mirror = "digest-only"

[[registry]]
  prefix = ""
  location = "registry.example.com/redhat"

  [[registry.mirror]]
    location = "mirror.example.com/redhat"
    pull-from-mirror = "digest-only"
[[registry]]
  prefix = ""
  location = "registry.access.redhat.com/ubi9/ubi-minimal"
  blocked = true

  [[registry.mirror]]
    location = "example.io/example/ubi-minimal-tag"
    pull-from-mirror = "tag-only"
      Copy to Clipboard Toggle word wrap

      where: [[registry]].location = "registry.access.redhat.com/ubi9/ubi-minimal":: The repository listed in a pull spec. [[registry.mirror]].location = "example.io/example/ubi-minimal":: Indicates the mirror for that repository. [[registry.mirror]].pull-from-mirror = "digest-only":: Means that the image pull from the mirror is a digest reference image. [[registry]].blocked = true:: Indicates that the NeverContactSource parameter is set for this repository. [[registry.mirror]].pull-from-mirror = "tag-only":: Indicates that the image pull from the mirror is a tag reference image.

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

      sh-4.2# podman pull --log-level=debug registry.access.redhat.com/ubi9/ubi-minimal@sha256:5cf...
      Copy to Clipboard Toggle word wrap

Troubleshooting

If the repository mirroring procedure does not work as described, use the following information about how repository mirroring works to help troubleshoot the problem:

  • The first working mirror is used to supply the pulled image.
  • The main registry is only used if no other mirror works.
  • From the system context, the Insecure flags are used as fallback.
  • The format of the /etc/containers/registries.conf file has changed recently. It is now version 2 and in TOML format.

9.5.2. Image registry repository mirroring configuration parameters
Copia collegamento

You can use the following table for information about parameters when configuring your image repository for mirroring.

Expand
ParameterValues and Information

apiVersion:

Required. The value must be config.openshift.io/v1 API.

kind:

The kind of object according to the pull type. The ImageDigestMirrorSet type pulls a digest reference image The ImageTagMirrorSet type pulls a tag reference image.

spec: imageDigestMirrors:

The type of image pull method. Use imageDigestMirrors`for an `ImageDigestMirrorSet CR. Use imageTagMirrors for an ImageTagMirrorSet CR.

- mirrors: - example.io/example/ubi-minimal

The name of the mirrored image registry and repository.

- mirrors: -example.com/example2/ubi-minimal

The value of this parameter is the name of a secondary mirror repository for each target repository. If one mirror is down the target repository can use the secondary mirror.

source: registry.access.redhat.com/ubi9/ubi-minimal

The registry and repository source. The source is the repository that is listed in an image pull specification.

mirrorSourcePolicy: AllowContactingSource

Optional parameter that indicates the fallback policy if the image pull fails. The AllowContactingSource value allows continued attempts to pull the image from the source repository. Default value. NeverContactSource prevents continued attempts to pull the image from the source repository.

source: registry.example.com/redhat: An optional parameter that indicates a namespace inside a registry. Setting a namespace inside a registry allows use of any image in that namespace. If you use a registry domain as a source, the object applies to all of the repositories from the registry.

source: registry.example.com

Optional parameter that indicates a registry. Allows us of any image in that registry. If you specify a registry name, the object applies to all repositories from a source registry to a mirror registry.

source: registry.example.com/example/myimage

Pulls the image registry.example.com/example/myimage@sha256:…​ from the mirror mirror.example.net/image@sha256:...

source: registry.example.com/example

Pulls the image registry.example.com/example/image@sha256:…​ in the source registry namespace from the mirror mirror.example.net/image@sha256:…​.

source: registry.example.com

Using an ImageContentSourcePolicy (ICSP) object to configure repository mirroring is a deprecated feature.

This functionality is still included in OpenShift Container Platform and continues to be supported; however, it will be removed in a future release of this product and is not recommended for new deployments.

ICSP objects are being replaced by ImageDigestMirrorSet and ImageTagMirrorSet objects to configure repository mirroring. If you have existing YAML files that you used to create ImageContentSourcePolicy objects, you can use the oc adm migrate icsp command to convert those files to an ImageDigestMirrorSet YAML file. The command updates the API to the current version, changes the kind value to ImageDigestMirrorSet, and changes spec.repositoryDigestMirrors to spec.imageDigestMirrors. The rest of the file is not changed.

Because the migration does not change the registries.conf file, the cluster does not need to reboot.

For more information about ImageDigestMirrorSet or ImageTagMirrorSet objects, see "Configuring image registry repository mirroring" in the previous section.

Prerequisites

  • Access to the cluster as a user with the cluster-admin role.
  • Ensure that you have ImageContentSourcePolicy objects on your cluster.

Procedure

  1. Use the following command to convert one or more ImageContentSourcePolicy YAML files to an ImageDigestMirrorSet YAML file: 

    $ oc adm migrate icsp <file_name>.yaml <file_name>.yaml <file_name>.yaml --dest-dir <path_to_the_directory>
    Copy to Clipboard Toggle word wrap

    where:

    <file_name>
    Specifies the name of the source ImageContentSourcePolicy YAML. You can list multiple file names.
    --dest-dir

    Optional: Specifies a directory for the output ImageDigestMirrorSet YAML. If unset, the file is written to the current directory.

    For example, the following command converts the icsp.yaml and icsp-2.yaml file and saves the new YAML files to the idms-files directory. 

    $ oc adm migrate icsp icsp.yaml icsp-2.yaml --dest-dir idms-files
    Copy to Clipboard Toggle word wrap

    Example output

    wrote ImageDigestMirrorSet to idms-files/imagedigestmirrorset_ubi8repo.5911620242173376087.yaml
wrote ImageDigestMirrorSet to idms-files/imagedigestmirrorset_ubi9repo.6456931852378115011.yaml
    Copy to Clipboard Toggle word wrap

  2. Create the CR object by running the following command: 

    $ oc create -f <path_to_the_directory>/<file-name>.yaml
    Copy to Clipboard Toggle word wrap

    where:

    <path_to_the_directory>
    Specifies the path to the directory, if you used the --dest-dir flag.
    <file_name>
    Specifies the name of the ImageDigestMirrorSet YAML.
  3. Remove the ICSP objects after the IDMS objects are rolled out.
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