From 2daygeek.com
Server patching is one of the important task of Linux system administrator to make the system more stable and better performance. All the vendors used to release security/vulnerabilities patches very often, the affected package must be updated in order to limit any potential security risks.
Yum (Yellowdog Update Modified) is RPM Package Management utility for CentOS and Red Hat systems, Yum history command allows administrator to rollback the system to a previous state but due to some limitations, rollbacks do not work in all situations, or The yum command may simply do nothing, or it may remove packages you do not expect.
I advise you to take a full system backup prior to performing any update/upgrade is always recommended, and yum history is NOT meant to replace systems backups. This will help you to restore the system to previous state at any point of time.
n some cases, the hosted applications might not work properly or through some error due to recent patch updates (It could be some library incompatibility or package upgrade), what will be the solution in this case?
Get in touch with App Dev team and figure it out an issue creating library' and packages then do the rollback with help of yum history command.
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