Using image pull secrets - Managing images | Images

Allowing pods to reference images across projects
Allowing pods to reference images from other secured registries
Updating the global cluster pull secret

To authenticate with container registries and pull images across OKD projects or from secured registries, you can configure and use image pull secrets.

You first obtain the registry authentication credentials, which are typically found in the ~/.docker/config.json file for Docker or the ~/.config/containers/auth.json file for Podman, created by the pull secret from Red Hat OpenShift Cluster Manager process. This content is then used to create or update the global pullSecret object within your cluster, allowing access to images from quay.io and registry.redhat.io.

If you are using the OpenShift image registry and are pulling from image streams located in the same project, then your pod service account should already have the correct permissions. No additional action should be required.

Allowing pods to reference images across projects

To allow pods in one OKD project to reference images from another project, you can bind a service account to the system:image-puller role in the target project. Use the oc policy add-role-to-user or oc policy add-role-to-group command to grant cross-project image access.

When you create a pod service account or a namespace, wait until the service account is provisioned with a Docker pull secret. If you create a pod before its service account is fully provisioned, the pod fails to access the OpenShift image registry.

Procedure

Allow pods in project-a to reference images in project-b by entering the follow command. In this example, the service account default in project-a is bound to the system:image-puller role in project-b:
```
$ oc policy add-role-to-user \
    system:image-puller system:serviceaccount:project-a:default \
    --namespace=project-b
```

Optional: Allow access for any service account in project-a by using the add-role-to-group flag. For example:

$ oc policy add-role-to-group \
    system:image-puller system:serviceaccounts:project-a \
    --namespace=project-b

Allowing pods to reference images from other secured registries

Pull secrets enable pods in OKD to authenticate with secured registries and pull container images. Docker and Podman store authentication credentials in configuration files that you can use to create pull secrets for your service accounts.

The following files store your authentication information if you have previously logged in to a secured or insecure registry:

Docker: By default, Docker uses $HOME/.docker/config.json.
Podman: By default, Podman uses $HOME/.config/containers/auth.json.

Both Docker and Podman credential files and the associated pull secret can contain multiple references to the same registry if they have unique paths, for example, quay.io and quay.io/<example_repository>. However, neither Docker nor Podman support multiple entries for the exact same registry path.

Example config.json file

{
   "auths":{
      "cloud.openshift.com":{
         "auth":"b3Blb=",
         "email":"you@example.com"
      },
      "quay.io":{
         "auth":"b3Blb=",
         "email":"you@example.com"
      },
      "quay.io/repository-main":{
         "auth":"b3Blb=",
         "email":"you@example.com"
      }
   }
}

Example pull secret

apiVersion: v1
data:
  .dockerconfigjson: ewogICAiYXV0aHMiOnsKICAgICAgIm0iOnsKICAgICAgIsKICAgICAgICAgImF1dGgiOiJiM0JsYj0iLAogICAgICAgICAiZW1haWwiOiJ5b3VAZXhhbXBsZS5jb20iCiAgICAgIH0KICAgfQp9Cg==
kind: Secret
metadata:
  creationTimestamp: "2021-09-09T19:10:11Z"
  name: pull-secret
  namespace: default
  resourceVersion: "37676"
  uid: e2851531-01bc-48ba-878c-de96cfe31020
type: Opaque

Creating a pull secret

To authenticate with container registries in OKD, you can create pull secrets from existing Docker or Podman authentication files. You can also create secrets by providing registry credentials directly by using the oc create secret docker-registry command.

Procedure

Create a secret from an existing authentication file:

For Docker clients using .docker/config.json, enter the following command:

$ oc create secret generic <pull_secret_name> \
    --from-file=.dockerconfigjson=<path/to/.docker/config.json> \
    --type=kubernetes.io/dockerconfigjson

For Podman clients using .config/containers/auth.json, enter the following command:

$ oc create secret generic <pull_secret_name> \
     --from-file=<path/to/.config/containers/auth.json> \
     --type=kubernetes.io/podmanconfigjson

Optional: If you do not already have a Docker credentials file for the secured registry, you can create a secret by running the following command:

$ oc create secret docker-registry <pull_secret_name> \
    --docker-server=<registry_server> \
    --docker-username=<user_name> \
    --docker-password=<password> \
    --docker-email=<email>

Using a pull secret in a workload

To allow workloads to pull images from private registries in OKD, you can link the pull secret to a service account by entering the oc secrets link command or by defining it directly in your workload configuration YAML file.

Procedure

Link the pull secret to a service account by entering the following command. Note that the name of the service account should match the name of the service account that pod uses. The default service account is default.
```
$ oc secrets link default <pull_secret_name> --for=pull
```

Verify the change by entering the following command:

$ oc get serviceaccount default -o yaml

Example output

apiVersion: v1
imagePullSecrets:
- name: default-dockercfg-123456
- name: <pull_secret_name>
kind: ServiceAccount
metadata:
  annotations:
    openshift.io/internal-registry-pull-secret-ref: <internal_registry_pull_secret>
  creationTimestamp: "2025-03-03T20:07:52Z"
  name: default
  namespace: default
  resourceVersion: "13914"
  uid: 9f62dd88-110d-4879-9e27-1ffe269poe3
secrets:
- name: <pull_secret_name>

Optional: Instead of linking the secret to a service account, you can alternatively reference it directly in your pod or workload definition. This is useful for GitOps workflows such as ArgoCD. For example:

Example pod specification

apiVersion: v1
kind: Pod
metadata:
  name: <secure_pod_name>
spec:
  containers:
  - name: <container_name>
    image: quay.io/my-private-image
  imagePullSecrets:
  - name: <pull_secret_name>

Example ArgoCD workflow

apiVersion: argoproj.io/v1alpha1
kind: Workflow
metadata:
  generateName: <example_workflow>
spec:
  entrypoint: <main_task>
  imagePullSecrets:
  - name: <pull_secret_name>

Pulling from private registries with delegated authentication

To pull images from private registries that delegate authentication to a separate service in OKD, you can create pull secrets for both the authentication server and the registry endpoint. Use the oc create secret docker-registry command to create separate secrets for each service.

Procedure

Create a secret for the delegated authentication server by entering the following command:

$ oc create secret docker-registry \
    --docker-server=sso.redhat.com \
    --docker-username=developer@example.com \
    --docker-password=******** \
    --docker-email=unused \
    redhat-connect-sso

Create a secret for the private registry by entering the following command:

$ oc create secret docker-registry \
    --docker-server=privateregistry.example.com \
    --docker-username=developer@example.com \
    --docker-password=******** \
    --docker-email=unused \
    private-registry

Updating the global cluster pull secret

To add new registries or change authentication for your OKD cluster, you can update the global pull secret by replacing it or appending new credentials. Use the oc set data secret/pull-secret command to apply the updated pull secret to all nodes in your cluster.

To transfer your cluster to another owner, you must initiate the transfer in OpenShift Cluster Manager and then update the pull secret on the cluster. Updating a cluster’s pull secret without initiating the transfer in OpenShift Cluster Manager causes the cluster to stop reporting Telemetry metrics in OpenShift Cluster Manager.

For more information, see "Transferring cluster ownership" in the Red Hat OpenShift Cluster Manager documentation.

Prerequisites

You have access to the cluster as a user with the cluster-admin role.

Procedure

Optional: To append a new pull secret to the existing pull secret:
1. Download the pull secret by entering the following command:
  $ oc get secret/pull-secret -n openshift-config --template='{{index .data ".dockerconfigjson" | base64decode}}' > <pull_secret_location> (1)
  where:
  
  <pull_secret_location>
  
  Specifies the path to the pull secret file.
2. Add the new pull secret by entering the following command:
  $ oc registry login --registry="<registry>" \ --auth-basic="<username>:<password>" \ --to=<pull_secret_location>
  where:
  
  <registry>
  
  Specifies the new registry. You can include many repositories within the same registry, for example: --registry="<registry/my-namespace/my-repository>.
  
  <username>:<password>
  
  Specifies the credentials of the new registry.
  
  <pull_secret_location>
  
  Specifies the path to the pull secret file.
Update the global pull secret for your cluster by entering the following command. Note that this update rolls out to all nodes, which can take some time depending on the size of your cluster.
```
$ oc set data secret/pull-secret -n openshift-config \
  --from-file=.dockerconfigjson=<pull_secret_location>
```
where:

<pull_secret_location>

Specifies the path to the new pull secret file.