Check which APT repo is being used¶

To determine which APT repository is being used for a specific package, you can follow these steps:

Step 1: Check the Pinned Priority¶

APT uses the repository with the highest priority. You can check the priority of each repository using the following command:

apt-cache policy

In this example, we will be looking for the docker-ce package (or any Docker-related package) in the output. It will show the repository URL and its priority. For example:

apt-cache policy docker-ce

Sample output:

docker-ce:
  Installed: (none)
  Candidate: 5:20.10.24~3-0~ubuntu-jammy
  Version table:
     5:20.10.24~3-0~ubuntu-jammy 500
        500 https://download.docker.com/linux/ubuntu jammy/stable amd64 Packages
     5:20.10.24~3-0~ubuntu-focal 500
        500 https://download.docker.com/linux/ubuntu focal/stable amd64 Packages

Step 2: Inspect the installed package¶

If Docker is already installed, you can check the version and match it to the repository:

apt-cache policy docker-ce

The output will show the installed version and the repository it came from.

Step 3: Manually check the repository¶

If you want to ensure only one repository is used, you can comment out or remove the unwanted entry in /etc/apt/sources.list.d/download_docker_com_linux_ubuntu.list. For example:

sudo nano /etc/apt/sources.list.d/download_docker_com_linux_ubuntu.list

Comment out the line for focal if you want to use jammy:

# deb [arch=amd64] https://download.docker.com/linux/ubuntu focal stable
deb [arch=amd64] https://download.docker.com/linux/ubuntu jammy stable

Then update the package cache:

sudo apt update

Step 4: Verify the repository again¶

After making changes, verify the repository being used:

apt-cache policy docker-ce