Resolving the PostgreSQL Connection Issue in Docker Containers

Описание: Learn how to solve the common issue of connecting to a PostgreSQL database running inside a Docker container from your local machine. This guide provides step-by-step instructions and useful tips.
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This video is based on the question https://stackoverflow.com/q/64765723/ asked by the user 'Max' ( https://stackoverflow.com/u/12563636/ ) and on the answer https://stackoverflow.com/a/64766525/ provided by the user 'Mous' ( https://stackoverflow.com/u/10446290/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Resolving the PostgreSQL Connection Issue in Docker Containers

Connecting to a PostgreSQL database hosted in a Docker container from your local machine can sometimes present challenges. If you're encountering difficulties connecting to your PostgreSQL instance, you're not alone. This post will walk you through the problem, and provide a clear solution to ensure you can successfully connect to your database.

The Problem: Unable to Connect to PostgreSQL

You set up your PostgreSQL container using Docker and can access the database inside the container; however, when you attempt to connect from your local machine, you only see the databases that exist locally, not the ones in your Docker container.

Consider the following commands you executed:

Creating the PostgreSQL container:

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Accessing the container:

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Starting PostgreSQL and creating a new database:

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After following these steps, you found that executing the command to connect from your local machine:

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only displayed local databases instead of your newly created mytestdb.

The Solution: Connecting Properly to PostgreSQL

The issue likely stems from how the database was created. It seems you addressed the command to create the database but might have missed a critical element. Here’s how to refine your approach to ensure proper connectivity:

Step 1: Verify Database Creation

Double-check the command you used to create the database. Make sure it is executed correctly, with proper syntax:

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Ensure that you include the semicolon (;) at the end of the command. This signals to PostgreSQL that the command is complete.

Step 2: Confirm Connection Details

Once the database is created correctly, attempt a connection again from your local machine. Use the following command:

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Step 3: Troubleshoot Connectivity Issues

If the problem persists, consider the following troubleshooting steps:

Check Docker Network Settings: Ensure that your Docker container is correctly set up to allow connections from outside. If needed, adjust the network settings.

Verify PostgreSQL Configuration: Look into the PostgreSQL configuration file (postgresql.conf). Ensure that the listen_addresses option is set to *, which allows connections from any IP address.

Inspect Access Rights: Ensure user permissions are adequate. Typically, using the default postgres user should work, but always check the access privileges.

Conclusion

By ensuring your database creation command is executed correctly and verifying your connection details and configurations, you can resolve the issue of connecting to a PostgreSQL database in a Docker container from your local machine. If you follow these steps and remain consistent in command execution, you’ll have no trouble accessing your database.

Keep learning and exploring the potential of Docker and PostgreSQL!