Configure fencing levels

Pacemaker supports fencing nodes with multiple devices through a feature called fencing topologies. To implement topologies, create the individual devices as you normally would and then define one or more fencing levels in the fencing topology section in the configuration.

Before you begin

  • You have configured an ilo fence device called my_ilo for node rh7-2.
  • You have configured an apc fence device called my_apc for node rh7-2.

About this task

Pacemaker processes fencing levels as follows:

  • Each level is attempted in ascending numeric order, starting at 1.
  • If a device fails, processing terminates for the current level. No further devices in that level are exercised and the next level is attempted instead.
  • If all devices are successfully fenced, then that level has succeeded and no other levels are tried.
  • The operation is finished when a level has passed (success), or all levels have been attempted (failed).

Use the following command to add a fencing level to a node. The devices are given as a comma-separated list of stonith ids, which are attempted for the node at that level.

# pcs stonith level add levelnodedevices

The following example configures fence levels so that if the device my_ilo fails and is unable to fence the node, then Pacemaker attempts to use the device my_apc.

Procedure

  1. Add a fencing level of 1 for fence device my_ilo on node rh7-2. 
    # pcs stonith level add 1 rh7-2 my_ilo
  2. Add a fencing level of 2 for fence device my_apc on node rh7-2. 
    # pcs stonith level add 2 rh7-2 my_apc
  3. List the currently configured fencing levels. 
    # pcs stonith level
     
     Node: rh7-2
  Level 1 - my_ilo
  Level 2 - my_apc