@Marvin I have a local k8s cluster with the Prefect server and worker deployed with the official helm charts. I have custom images stored in a harbor private registry. The prefect deployment points to this custom base image. When I try to run the flow, the worker pod can't authenticate to harbor registry to pull the custom image. I have created k8s secret that contain the credentials to authenticate to the harbor registry. How and in which helm chart files should I set the harbor registry credentials stored in k8s secret?

To authenticate the worker pod to the harbor registry and pull the custom image, you need to refer to the Kubernetes secret that contains the credentials for the registry within your Helm chart configuration. Although the Prefect documentation doesn't cover this specific instruction, in general, when deploying to Kubernetes, you can use an

ImagePullSecrets

field in your deployment to specify the name of the secret containing your Docker credentials. With Helm, you would typically add something like this to your

values.yaml

file for the Helm chart when deploying your Prefect components:

yaml
imagePullSecrets:
  - name: <your-registry-secret-name>

Where

<your-registry-secret-name>

is the name of the Kubernetes secret you created for the harbor registry credentials. Please note that the specific location within the

values.yaml

file can vary depending on how the Helm chart is structured so you may need to adjust it accordingly or reference the Helm chart documentation for Prefect. Alternatively, the Kubernetes documentation provides steps for creating an imagePullSecret and using it with a service account. If the Prefect Helm chart doesn't directly support specifying

imagePullSecrets

, you can create a service account that includes the secret and then configure the Helm chart to use that service account for the deployments. Here are the general steps: 1. Ensure your secret is created in the same namespace as where you're deploying Prefect.

sh
   kubectl create secret docker-registry <your-registry-secret-name> \
   --docker-server=<your-harbor-registry-server> \
   --docker-username=<your-username> \
   --docker-password=<your-password> \
   --docker-email=<your-email> \
   --namespace=<your-prefect-namespace>

2. Create a service account in Kubernetes or use an existing one. 3. Attach the

imagePullSecret

to the service account.

sh
   kubectl patch serviceaccount <your-service-account-name> \
   --namespace=<your-prefect-namespace> \
   -p "{\"imagePullSecrets\": [{\"name\": \"<your-registry-secret-name>\"}]}"

4. Configure the Prefect Helm chart to use the modified service account for deployments. As a side note, keep in mind the information provided here is a general Kubernetes/Helm practice and not specific to Prefect. For detailed instructions, consult the Kubernetes documentation on imagePullSecrets and check the Prefect Helm chart documentation for any chart-specific configuration. If you need further assistance, you might want to check the Prefect Kubernetes Deployment Guide or consult with the Prefect community for help specific to your situation.

@Marvin After upgrading worker helm chart values with

pullSecrets:
  - harbor-registry-secret

I get the following log error in the worker pod when I try to run the deployed flow: 100957.650 | INFO | prefect.flow_runs.worker - Pod event 'Pulling' (3 times) at 2024-05-15 100940+0000 Pulling image "xyz" 100957.650 | INFO | prefect.flow_runs.worker - Pod event 'Failed' (3 times) at 2024-05-15 100941+0000 Failed to pull image "xyz": rpc error: code = Unknown desc = failed to pull and unpack image "xyz": failed to resolve reference "xyz": pulling from host x failed with status code [manifests x]: 401 Unauthorized 100957.651 | INFO | prefect.flow_runs.worker - Pod event 'Failed' (3 times) at 2024-05-15 100941+0000 Error: ErrImagePull Any suggestion?

Seeing the

"401 Unauthorized"

error when pulling the image from the registry suggests there's an issue with the authentication. The image name

"xyz"

is also suspicious—it looks like a placeholder, which could be part of the problem. You must ensure that the correct and complete image name is specified, including the registry URL, repository, and tag (if needed). Here are some steps and checks you might want to perform: 1. Verify Image Name: Ensure the image name in your flow configuration includes the full path to the harbor registry, including the port if necessary, like

<http://harbor-registry.yourdomain.com/your-namespace/your-image:tag|harbor-registry.yourdomain.com/your-namespace/your-image:tag>

. 2. Check Secret Name: Make sure the name of the secret specified in helm chart values matches the actual secret name in Kubernetes which contains the credentials for the harbor registry. 3. Inspect Secret Content: Double-check the secret's data to ensure it has the correct structure and contains valid credentials (

kubectl get secret harbor-registry-secret -n <your-prefect-namespace> -o yaml

). 4. Review Service Account: If your pods run with a specific service account, ensure that the

imagePullSecrets

are correctly attached to that service account. 5. Helm Chart Values Syntax: The correct key for specifying image pull secrets in Helm chart values might differ. In some charts, it's

imagePullSecrets

and in others, it could be

pullSecrets

. Refer to the Helm chart documentation for the specific key to use. 6. Regenerate Secret: If you are still facing issues, try to delete and recreate the secret in Kubernetes with correct harbor registry credentials. 7. Look for Issues in GitHub: Finally, if you've confirmed everything is correct on your end, there might be an issue with Prefect or the Kubernetes cluster. It might be helpful to look for similar problems reported on GitHub to see if others have found a solution, which you have already started looking into. Since the GitHub issue I found doesn't seem directly related to the problem you're experiencing, if none of the above checks resolve the issue, you could: - Check other issues in the Prefect GitHub repository related to image pull errors for further clues. - Contact support or the Prefect community on Slack or forums for more specific help. - Make sure the Kubernetes nodes themselves have network access to the registry and that no firewall or security group is blocking the requests.