Скачать или смотреть Resolving FATAL: password authentication failed for user "username" in Minikube for PostgreSQL

Learn how to troubleshoot and fix the `psycopg2.OperationalError` in a Flask app running on Minikube when connecting to PostgreSQL.
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Troubleshooting psycopg2.OperationalError in Minikube: Password Authentication Failed

If you’re developing a multi-container application using Flask and PostgreSQL deployed on Minikube, encountering errors can be a frustrating experience. One common issue that developers face is the psycopg2.OperationalError: FATAL: password authentication failed for user "username". In this guide, we will explore how to diagnose and fix this error in a structured and easy-to-follow manner.

Understanding the Problem

In the context of a Flask app that interacts with a PostgreSQL database, this error typically indicates a problem with user authentication. Here’s a brief breakdown of the scenario:

Multi-container setup: The application includes a Flask web container, a PostgreSQL container for database services, and a Redis container for caching.

Environment variables: The credentials for connecting to PostgreSQL (username, database name, and password) are specified as environment variables in your deployment files.

Error occurrence: When the web container attempts to connect to the PostgreSQL container, it raises an authentication error, indicating that the credentials provided are incorrect.

The Root Cause

Upon investigation, it was found that although the password was specified correctly in the postgres_deployment.yaml file, the username and database name were not set in a manner that matched what the Flask app was attempting to use for the connection. This mismatch causes the password authentication to fail.

Solution Steps

To resolve the authentication issue, you’ll need to ensure that the username and database name are correctly specified in your PostgreSQL deployment configuration. Here’s how to do it:

Step 1: Update postgres_deployment.yaml

Make sure that your postgres_deployment.yaml includes the following environment variables as part of the PostgreSQL container configuration:

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Step 2: Verify Environment Variables in web_deployment.yaml

Check your web_deployment.yaml file to ensure that the environment variables for the PostgreSQL connection match what you’ve just defined in postgres_deployment.yaml:

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Step 3: Redeploy Your Application

After making the necessary updates, you'll need to redeploy the Docker containers to apply the changes. Use the following commands to do so:

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Conclusion

By ensuring that the username, database name, and password are specified consistently across your deployment configurations, you can effectively resolve the password authentication failed error when connecting to PostgreSQL from your Flask app. This simple oversight is a common pitfall but can be easily rectified with a structured approach.

Now you're all set to run your application without authentication hiccups. Happy coding!