If you've encountered the NO_PUBKEY
error on Ubuntu, it means that a repository's public key is missing from your keyring. This guide will help you add the missing key and keep your system running smoothly.
The NO_PUBKEY
error indicates that a repository's GPG key isn't present in your keyring, preventing the verification of packages from that repository. This verification ensures that the packages you install are authentic and secure.
First, identify the key ID from the error message. In the example above, the key ID is 0123456789ABCDEF
.
Use the following command to fetch the missing key from a key server.
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 0123456789ABCDEF
Finally, update your system to apply the changes.
sudo apt-get update
Some repositories specify their GPG keys directly in their configuration files. Here’s how to handle these cases.
Identify the Key ID
Find the key ID in the error message. For example, 9DC858229FC7DD38854AE2D88D81803C0EBFCD88
.
Fetch the Missing Key
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
Update the Repository Configuration
Ensure your repository configuration file points to the updated keyring file. For example, edit /etc/apt/sources.list.d/docker.list
:
deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable
Update Your System
sudo apt-get update
For repositories that specify their keys, follow these steps:
Identify the Key ID
Find the key ID in the error message or repository documentation.
Fetch the Missing Key
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys <KEY_ID>
Update the Repository Configuration
Ensure the repository configuration file points to the updated keyring file.
Update Your System
sudo apt-get update
Suppose you have a custom repository configured like this:
deb [signed-by=/usr/share/keyrings/custom-archive-keyring.gpg] https://example.com/ubuntu focal main
Identify the Key ID
Assume the key ID is 1234567890ABCDEF
.
Fetch the Missing Key
curl -fsSL https://example.com/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/custom-archive-keyring.gpg
Update the Repository Configuration
Ensure your repository configuration points to the updated key file.
deb [signed-by=/usr/share/keyrings/custom-archive-keyring.gpg] https://example.com/ubuntu focal main
Update Your System
sudo apt-get update
By following these steps, you can resolve the NO_PUBKEY
error on your Ubuntu system, ensuring your repositories remain functional and secure.
The NO_PUBKEY
error can be frustrating, but it's a critical part of maintaining the security and integrity of your package management on Ubuntu. Regularly updating your GPG keys and following the latest methods will keep your system safe and up-to-date. If you encounter this issue, refer back to this guide for a straightforward solution.