FENCE_NODE(8)							      cluster							     FENCE_NODE(8)

NAME

       fence_node - a utility to run fence agents

SYNOPSIS

       fence_node [OPTIONS] nodename

DESCRIPTION

       This  utility  runs  a  fence  agent  against nodename.	The agent and args are taken from the running cluster configuration based on clus-
       ter.conf(5).

       fence_node is a wrapper around the libfence functions: fence_node() and unfence_node().	These libfence functions use libccs  to  read  the
       node fencing configuration, which means that corosync (with cman and ccs) must be running to use fence_node(8).

       The  fenced(8) daemon is the main user of libfence:fence_node(), and the configuration details for that function are given in the fenced(8)
       man page.

   Fencing vs. Unfencing
       The main use for unfencing is with storage/SAN (non-power) agents.

       When using power-based fencing agents, the fencing action itself is supposed to turn a node back on after first turning the power off (this
       happens automatically with a "reboot" action, and needs to be configured explicitly as "off" + "on" otherwise.)

       When  using  storage-based  fencing agents, the fencing action is not allowed to re-enable a node after disabling it.  Re-enabling a fenced
       node is only safe once the node has been rebooted.  A natural way to re-enable a fenced node's access to storage, is for that node  to  re-
       enable  the  access  itself during its startup process.	The cman init script calls fence_node -U (nodename defaults to local nodename when
       unfencing).  Unfencing a node without an <unfence> configuration (see below) is a no-op.

       The basic differences between fencing and unfencing:

       Fencing

       1. libfence: fence_node(), command line: fence_node nodename

       2. Turns off or disables a node.

       3. Agents run with the default action of "off", "disable" or "reboot".

       4. Performed by a cluster node against another node that fails (by the fenced daemon).

       Unfencing

       1. libfence: unfence_node(), command line: fence_node -U nodename

       2. Turns on or enables a node.

       3. Agents run with the explicit action of "on" or "enable".

       4. Performed by a cluster node "against" itself during startup (by the cman init script).

OPTIONS

       -U     Unfence the node, default local node name.

       -v     Show fence agent results, -vv to also show agent args.

       -h     Print a help message describing available options, then exit.

       -V     Print program version information, then exit.

FILES

       The Unfencing/unfence_node() configuration is very similar to the Fencing/fence_node() configuration shown in fenced(8).  Unfencing is only
       performed for a node with an <unfence> section:

       <clusternode name="node1" nodeid="1">
	       <fence>
	       </fence>
	       <unfence>
	       </unfence>
       </clusternode>

       The  <unfence>  section	does not contain <method> sections like the <fence> section does.  It contains <device> references directly, which
       mirror the corresponding device sections for <fence>, with the notable addition of the explicit action  of  "on"  or  "enable".	 The  same
       <fencedevice> is referenced by both fence and unfence <device> lines, and the same per-node args should be repeated.

       <clusternode name="node1" nodeid="1">
	       <fence>
	       <method name="1">
	       <device name="myswitch" foo="x"/>
	       </method>
	       </fence>

	       <unfence>
	       <device name="myswitch" foo="x" action="on"/>
	       </unfence>
       </clusternode>

SEE ALSO

       fenced(8)

cluster 							    2009-12-21							     FENCE_NODE(8)