Session Request Always 401 Behind Load Balancer

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Introduction

In this article, we will explore a common issue encountered when deploying Metabase behind an Application Load Balancer (ALB) on AWS ECS. The problem arises when attempting to login to Metabase or create a new user, resulting in a 401 Unauthorized response from the session call. We will delve into the possible causes and provide a step-by-step guide to resolve this issue.

Describe the Bug

We are deploying Metabase to AWS ECS with Terraform, using the official image with the latest version 0.54.x. Our custom start script starts the app /app/run_metabase.sh & and sets up the Admin User via a HTTP call. Everything works fine, and the running ECS task registers itself to the target group, which is referenced by our Application Load Balancer. The ALB handles TLS termination, while the target group uses plain HTTP.

However, when we attempt to login to Metabase or create a new user, we receive a 401 Unauthorized response from the session call. We have checked multiple times that the password and everything is correct, and since we can see that the UI is being served, the general connection seems to be fine.

To Reproduce

To reproduce this issue, follow these steps:

  1. Deploy the HTTP version of Metabase to AWS ECS Fargate.
  2. Register the task to a target group that is being used by a load balancer that is secured with a cert.
  3. Attempt to setup Metabase in the GUI.

Expected Behavior

We expect to be able to login to Metabase, since we created a user via HTTP call in our setup script, and/or create a new user via the /setup GUI.

Logs

No response is provided in the logs.

Information about your Metabase Installation

Since we cannot login, we cannot paste the JSON configuration.

Severity

This issue is blocking, as it prevents us from accessing Metabase.

Additional Context

  • We are using the official Metabase image with the latest version 0.54.x.
  • Our custom start script starts the app /app/run_metabase.sh & and sets up the Admin User via a HTTP call.
  • We have set the ENV MB_SITE_URL to our https://xyz.com URL.
  • The ALB handles TLS termination, while the target group uses plain HTTP.

Possible Causes

Based on the provided information, there are several possible causes for this issue:

  1. TLS Termination: The ALB handles TLS termination, while the target group uses plain HTTP. This might cause issues with the session call, as it expects a secure connection.
  2. Certificate Issues: There might be issues with the certificate used by the ALB, which could cause the session call to fail.
  3. Target Group Configuration: The target group configuration might be incorrect, causing the session call to fail.
  4. Metabase Configuration: The Metabase configuration might be incorrect, causing the session call to fail.

Resolving the Issue

To resolve this issue, follow these steps:

  1. Verify the Certificate: Verify that the certificate used by the ALB is correct and properly configured.
  2. Check the Target Group Configuration: Check the target group configuration to ensure that it is correct and properly configured.
  3. Verify the Metabase Configuration: Verify that the Metabase configuration is correct and properly configured.
  4. Use a Secure Connection: Use a secure connection (HTTPS) for the session call.
  5. Check the Logs: Check the logs to see if there are any errors or issues that might be causing the session call to fail.

Conclusion

Q: What is the cause of the 401 Unauthorized response from the session call?

A: The cause of the 401 Unauthorized response from the session call can be due to several reasons, including:

  • TLS Termination: The ALB handles TLS termination, while the target group uses plain HTTP. This might cause issues with the session call, as it expects a secure connection.
  • Certificate Issues: There might be issues with the certificate used by the ALB, which could cause the session call to fail.
  • Target Group Configuration: The target group configuration might be incorrect, causing the session call to fail.
  • Metabase Configuration: The Metabase configuration might be incorrect, causing the session call to fail.

Q: How can I verify the certificate used by the ALB?

A: To verify the certificate used by the ALB, follow these steps:

  1. Log in to the AWS Management Console.
  2. Navigate to the EC2 dashboard.
  3. Select the load balancer that is experiencing issues.
  4. Click on the "Actions" dropdown menu and select "Edit load balancer".
  5. Click on the "Listeners" tab.
  6. Select the listener that is experiencing issues.
  7. Click on the "Edit" button.
  8. Verify that the certificate is correct and properly configured.

Q: How can I check the target group configuration?

A: To check the target group configuration, follow these steps:

  1. Log in to the AWS Management Console.
  2. Navigate to the EC2 dashboard.
  3. Select the target group that is experiencing issues.
  4. Click on the "Actions" dropdown menu and select "Edit target group".
  5. Verify that the target group configuration is correct and properly configured.

Q: How can I verify the Metabase configuration?

A: To verify the Metabase configuration, follow these steps:

  1. Log in to the Metabase dashboard.
  2. Click on the "Settings" icon.
  3. Select "Configuration".
  4. Verify that the Metabase configuration is correct and properly configured.

Q: How can I use a secure connection for the session call?

A: To use a secure connection for the session call, follow these steps:

  1. Log in to the AWS Management Console.
  2. Navigate to the EC2 dashboard.
  3. Select the load balancer that is experiencing issues.
  4. Click on the "Actions" dropdown menu and select "Edit load balancer".
  5. Click on the "Listeners" tab.
  6. Select the listener that is experiencing issues.
  7. Click on the "Edit" button.
  8. Select the "HTTPS" protocol.
  9. Verify that the certificate is correct and properly configured.

Q: What are the common issues that can cause the session call to fail?

A: The common issues that can cause the session call to fail include:

  • TLS Termination: The ALB handles TLS termination, while the target group uses plain HTTP.
  • Certificate Issues: There might be issues with the certificate used by the ALB.
  • Target Group Configuration: The target group configuration might be incorrect.
  • Metabase Configuration: The Metabase configuration might be incorrect.

Q: How can I troubleshoot the issue?

A: To troubleshoot the issue, follow these steps:

  1. Check the logs to see if there are any errors or issues that might be causing the session call to fail.
  2. Verify the certificate used by the ALB.
  3. Check the target group configuration.
  4. Verify the Metabase configuration.
  5. Use a secure connection for the session call.

Q: What are the best practices for deploying Metabase behind an ALB on AWS ECS?

A: The best practices for deploying Metabase behind an ALB on AWS ECS include:

  • Using a secure connection (HTTPS) for the session call.
  • Verifying the certificate used by the ALB.
  • Checking the target group configuration.
  • Verifying the Metabase configuration.
  • Using a load balancer that handles TLS termination.
  • Using a target group that uses a secure connection (HTTPS).