5.4. Using image pull secrets
If you are using the OpenShift Container Platform internal registry and are pulling from image streams located in the same project, then your pod service account should already have the correct permissions and no additional action should be required.
However, for other scenarios, such as referencing images across OpenShift Container Platform projects or from secured registries, then additional configuration steps are required.
You can obtain the image pull secret, pullSecret, from the Pull Secret page on the Red Hat OpenShift Cluster Manager site.
You use this pull secret to authenticate with the services that are provided by the included authorities, including Quay.io and registry.redhat.io, which serve the container images for OpenShift Container Platform components.
Example config.json file
{
"auths":{
"cloud.openshift.com":{
"auth":"b3Blb=",
"email":"you@example.com"
},
"quay.io":{
"auth":"b3Blb=",
"email":"you@example.com"
}
}
}
5.4.1. Allowing pods to reference images across projects
When using the internal registry, to allow pods in project-a to reference images in project-b, a service account in project-a must be bound to the system:image-puller role in project-b.
Procedure
To allow pods in
project-ato reference images inproject-b, bind a service account inproject-ato thesystem:image-pullerrole inproject-b:$ oc policy add-role-to-user \ system:image-puller system:serviceaccount:project-a:default \ --namespace=project-bAfter adding that role, the pods in
project-athat reference the default service account are able to pull images fromproject-b.To allow access for any service account in
project-a, use the group:$ oc policy add-role-to-group \ system:image-puller system:serviceaccounts:project-a \ --namespace=project-b
5.4.2. Allowing pods to reference images from other secured registries
The .dockercfg $HOME/.docker/config.json file for Docker clients is a Docker credentials file that stores your authentication information if you have previously logged into a secured or insecure registry.
To pull a secured container image that is not from OpenShift Container Platform’s internal registry, you must create a pull secret from your Docker credentials and add it to your service account.
Procedure
If you already have a
.dockercfgfile for the secured registry, you can create a secret from that file by running:$ oc create secret generic <pull_secret_name> \ --from-file=.dockercfg=<path/to/.dockercfg> \ --type=kubernetes.io/dockercfgOr if you have a
$HOME/.docker/config.jsonfile:$ oc create secret generic <pull_secret_name> \ --from-file=.dockerconfigjson=<path/to/.docker/config.json> \ --type=kubernetes.io/dockerconfigjsonIf you do not already have a Docker credentials file for the secured registry, you can create a secret by running:
$ oc create secret docker-registry <pull_secret_name> \ --docker-server=<registry_server> \ --docker-username=<user_name> \ --docker-password=<password> \ --docker-email=<email>To use a secret for pulling images for pods, you must add the secret to your service account. The name of the service account in this example should match the name of the service account the pod uses. The default service account is
default:$ oc secrets link default <pull_secret_name> --for=pull
5.4.2.1. Pulling from private registries with delegated authentication
A private registry can delegate authentication to a separate service. In these cases, image pull secrets must be defined for both the authentication and registry endpoints.
Procedure
Create a secret for the delegated authentication server:
$ oc create secret docker-registry \ --docker-server=sso.redhat.com \ --docker-username=developer@example.com \ --docker-password=******** \ --docker-email=unused \ redhat-connect-sso secret/redhat-connect-ssoCreate a secret for the private registry:
$ oc create secret docker-registry \ --docker-server=privateregistry.example.com \ --docker-username=developer@example.com \ --docker-password=******** \ --docker-email=unused \ private-registry secret/private-registry
5.4.3. Updating the global cluster pull secret
You can update the global pull secret for your cluster.
Cluster resources must adjust to the new pull secret, which can temporarily limit the usability of the cluster.
Updating the global pull secret will cause node reboots while the Machine Config Operator (MCO) syncs the changes.
Prerequisites
- You have a new or modified pull secret file to upload.
-
You have access to the cluster as a user with the
cluster-adminrole.
Procedure
Enter the following command to update the global pull secret for your cluster:
$ oc set data secret/pull-secret -n openshift-config --from-file=.dockerconfigjson=<pull-secret-location> 1- 1
- Provide the path to the new pull secret file.
This update is rolled out to all nodes, which can take some time depending on the size of your cluster. During this time, nodes are drained and pods are rescheduled on the remaining nodes.
