Updating the kernel is extremely slow (~40 minutes or more)

Issue

• When updating/installing a kernel, the yum command is extremely slow during post-installation step, as shown in the example below

  # yum -y update kernel
  [...]
  Dependencies Resolved
  
  ================================================================================
   Package        Arch           Version                         Repository  Size
  ================================================================================
  Installing:
   kernel         x86_64         3.10.0-1062.12.1.el7            os          50 M
  
  Transaction Summary
  ================================================================================
  Install  1 Package
  
  Total download size: 50 M
  Installed size: 64 M
  [...]
  Running transaction
    Installing : kernel-3.10.0-1062.12.1.el7.x86_64                           1/1 
  
  ---> "Hang" here