Troubleshoot the deployed server

Troubleshooting tips for your ZenML deployment

In this document, we will go over some common issues that you might face when deploying ZenML and how to solve them.

Viewing logs

Analyzing logs is a great way to debug issues. Depending on whether you have a Kubernetes (using Helm or zenml deploy) or a Docker deployment, you can view the logs in different ways.

If you are using Kubernetes, you can view the logs of the ZenML server using the following method:

  • Check all pods that are running your ZenML deployment.

kubectl -n <KUBERNETES_NAMESPACE> get pods
  • If you see that the pods aren't running, you can use the command below to get the logs for all pods at once.

kubectl -n <KUBERNETES_NAMESPACE> logs -l app.kubernetes.io/name=zenml

Note that the error can either be from the zenml-db-init container that connects to the MySQL database or from the zenml container that runs the server code. If the get pods command shows that the pod is failing in the Init state then use zenml-db-init as the container name, otherwise use zenml.

kubectl -n <KUBERNETES_NAMESPACE> logs -l app.kubernetes.io/name=zenml -c <CONTAINER_NAME>

You can also use the --tail flag to limit the number of lines to show or the --follow flag to follow the logs in real-time.

Fixing database connection problems

If you are using a MySQL database, you might face issues connecting to it. The logs from the zenml-db-init container should give you a good idea of what the problem is. Here are some common issues and how to fix them:

  • If you see an error like ERROR 1045 (28000): Access denied for user <USER> using password YES, it means that the username or password is incorrect. Make sure that the username and password are correctly set for whatever deployment method you are using.

  • If you see an error like ERROR 2003 (HY000): Can't connect to MySQL server on <HOST> (<IP>), it means that the host is incorrect. Make sure that the host is correctly set for whatever deployment method you are using.

You can test the connection and the credentials by running the following command from your machine:

mysql -h <HOST> -u <USER> -p

If you are using a Kubernetes deployment, you can use the kubectl port-forward command to forward the MySQL port to your local machine. This will allow you to connect to the database from your machine.

Fixing database initialization problems

If youโ€™ve migrated from a newer ZenML version to an older version and see errors like Revision not found in your zenml-db-init logs, one way out is to drop the database and create a new one with the same name.

  • Log in to your MySQL instance.

    mysql -h <HOST> -u <NAME> -p
  • Drop the database for the server.

    drop database <NAME>;
  • Create the database with the same name.

    create database <NAME>;
  • Restart the Kubernetes pods or the docker container running your server to trigger the database initialization again.

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