Error: another app is currently holding the yum lock - Solution and Explanation

If you're trying to install Docker on your machine using the yum package manager and you see the error "Error: another app is currently holding the yum lock," it means that another application is currently using the package manager. This can prevent you from installing or updating packages.

To fix this error, you can try stopping the other application or restarting your machine to release the lock. You can also try running "yum clean all" to clear the package cache and try the installation again.

Here's an example of the correct command to install Docker on CentOS:

sudo yum update
sudo yum install docker-ce

Make sure you're using the correct package name "docker-ce" and that you've spelled it correctly. If you're still having trouble, you can try specifying the version of Docker you want to install by using the "--version" flag:

sudo yum update
sudo yum install docker-ce-<VERSION>

Replace "<VERSION>" with the desired version number. You can find a list of available versions by running "yum list docker-ce" and looking at the "Version" column.

If you've tried all of these steps and you're still seeing the "Error: another app is currently holding the yum lock" error, it may be due to a problem with the package repository. You can try switching to a different package repository or using a different package manager to install Docker.