#repositories

yum "Cannot find a valid baseurl for repo": CentOS 7 reached end of life, so use the vault

Fix yum "Cannot find a valid baseurl for repo: base/7/x86_64" and the CentOS 8 mirrorlist error: point the repositories at vault.centos.org, then plan a migration.

Beginner · 3 min read

NO_PUBKEY

Linux

apt "GPG error: NO_PUBKEY": add the key the right way, without apt-key

Fix apt "GPG error: The following signatures couldn't be verified: NO_PUBKEY": add the vendor's key to /etc/apt/keyrings with signed-by, and why apt-key is gone.

Intermediate · 4 min read

Unable to locate package

Linux

apt "E: Unable to locate package": update, enable the component, or find its real name

Fix apt "E: Unable to locate package": run apt update, enable universe or contrib, find the right package name, add the vendor's repository, and handle Docker images.

Beginner · 4 min read