How to create docker registry credentials using kubectl

Updating a Docker registry secret (often named regcred in Kubernetes environments) with new credentials can be essential for workflows that need access to private registries for pulling images. This process involves creating a new secret with the updated credentials and then patching or updating the deployments or pods that use this secret.

Here’s a step-by-step guide to do it:

Step 1: Create a New Secret with Updated Credentials

1. Log in to Docker Registry: Before updating the secret, ensure you’re logged into the Docker registry from your command line interface so that Kubernetes can access it.
2. Create or Update the Secret: Use the kubectl create secret command to create a new secret or update an existing one with your Docker credentials. If you’re updating an existing secret, you might need to delete the old secret first. To create a new secret (or replace an existing one)

kubectl create secret docker-registry regcred \
  --docker-server=<YOUR_REGISTRY_SERVER> \ # The URL of your Docker registry
  --docker-username=<YOUR_USERNAME> \ # Your Docker registry username
  --docker-password=<YOUR_PASSWORD> \ # Your Docker registry password
  --docker-email=<YOUR_EMAIL> \ # Your Docker registry email
  --namespace=<NAMESPACE> \ # The Kubernetes namespace where the secret will be used
  --dry-run=client -o yaml | kubectl apply -f -

Replace <YOUR_REGISTRY_SERVER>, <YOUR_USERNAME>, <YOUR_PASSWORD>, <YOUR_EMAIL>, and <NAMESPACE> with your Docker registry details and the appropriate namespace. The --dry-run=client -o yaml | kubectl apply -f - part generates the secret definition and applies it to your cluster, effectively updating the secret if it already exists.

Step 2: Update Deployments or Pods to Use the New Secret

If you’ve created a new secret with a different name, you’ll need to update your deployment or pod specifications to reference the new secret name. This step is unnecessary if you’ve updated an existing secret.

1. Edit Deployment or Pod Specification: Locate your deployment or pod definition files (YAML files) and update the imagePullSecrets section to reference the new secret name if it has changed.
2. Apply the Changes: Use kubectl apply -f <deployment-or-pod-file>.yaml to apply the changes to your cluster.

Step 3: Verify the Update

Ensure that your deployments or pods can successfully pull images using the updated credentials.

1. Check Pod Status: Use kubectl get pods to check the status of your pods. Ensure they are running and not stuck in a ImagePullBackOff or similar error status due to authentication issues.
2. Check Logs: For further verification, check the logs of your pods or deployments to ensure there are no errors related to pulling images from the Docker registry. You can use kubectl logs <pod-name> to view logs.

This method ensures that your Kubernetes deployments can continue to pull images from private registries without interruption, using the updated credentials.