When I'm trying to update in CentOS 8 using the "yum update" command, received an "Error: Failed to download metadata for repo 'AppStream': Cannot prepare internal mirrorlist: No URLs in mirrorlist"

You may get an error are Yum attempting to Update or when you installing Packages, 404 Error Returned.

We can upgrade or downgrade the packages using yum or rpm command in Linux and unix system. There are two way roll back an rpm,

The Server Administrator some times get an error like, Another app is currently holding the yum lock because already running yum command in background so want to kill the existing process and try to start.

By default RHEL packages are signed with the RH gpg key. Before start the yum installation verifies gpg key.

You may get an error while installing or update packages using YUM command on Linux system, Error: database disk image is malformed.

On previous post we have described about yum install, update, upgrade, remove, reinstall packages. The basic yum commands are below,