====== Yum ======

**General Information**

YellowDog Update Manager (yum) . 

**Checklist**
  * Distro(s): Enterprise Linux

----

====== Kernel Maintenance ======

View Installed Kernels
<code bash>
rpm -q kernel
</code>

**Remove Old Kernels**

  - Install yum utils<code bash>yum install yum-utils</code>
  - Cleanup, set count to how many old kernels you want to remain<code bash>package-cleanup --oldkernels --count=3</code>
  - Set number of installed kernels as a persistent setting<code bash>vim /etc/yum.conf

installonly_limit=3</code>

----

====== Package Version Locking ======

Lock packages at specific versions to prevent them from being upgraded with "yum update".

Install the version lock yum plugin
<code bash>
yum install yum-plugin-versionlock
</code>
\\

Lock httpd package at the current installed version
<code bash>
yum versionlock httpd
</code>
\\

List version locked entries
<code bash>
yum versionlock list
</code>
\\

Remove httpd from being version locked
<code bash>
yum versionlock delete httpd
</code>
\\

Remove all packages from being version locked
<code bash>
yum versionlock clear
</code>

----

====== Package Excludes ======

Exclude packages from a yum update, temporarily and persistently.

Exclude one time
<code bash>
yum update --exclude=kernel*
</code>
\\

Exclude persistently
<code bash>
vim /etc/yum.conf

exclude=kernel* httpd*
</code>

----