1FENCE_NODE(8)                       cluster                      FENCE_NODE(8)
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NAME

6       fence_node - a utility to run fence agents
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SYNOPSIS

10       fence_node [OPTIONS] nodename
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DESCRIPTION

14       This  utility  runs a fence agent against nodename.  The agent and args
15       are taken  from  the  running  cluster  configuration  based  on  clus‐
16       ter.conf(5).
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19       fence_node is a wrapper around the libfence functions: fence_node() and
20       unfence_node().  These libfence functions use libccs to read  the  node
21       fencing  configuration,  which  means that corosync (with cman and ccs)
22       must be running to use fence_node(8).
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25       The fenced(8) daemon is the main user of libfence:fence_node(), and the
26       configuration  details for that function are given in the fenced(8) man
27       page.
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30   Fencing vs. Unfencing
31       The main use for unfencing is with storage/SAN (non-power) agents.
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34       When using power-based fencing agents, the  fencing  action  itself  is
35       supposed to turn a node back on after first turning the power off (this
36       happens automatically with a "reboot" action, and needs to  be  config‐
37       ured explicitly as "off" + "on" otherwise.)
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40       When  using  storage-based  fencing  agents,  the fencing action is not
41       allowed to re-enable a node after disabling it.  Re-enabling  a  fenced
42       node  is  only  safe once the node has been rebooted.  A natural way to
43       re-enable a fenced node's access to storage, is for that  node  to  re-
44       enable  the  access  itself  during its startup process.  The cman init
45       script calls fence_node -U (nodename defaults to  local  nodename  when
46       unfencing).   Unfencing  a node without an <unfence> configuration (see
47       below) is a no-op.
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50       The basic differences between fencing and unfencing:
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52       Fencing
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54       1. libfence: fence_node(), command line: fence_node nodename
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56       2. Turns off or disables a node.
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58       3. Agents run with the default action of "off", "disable" or "reboot".
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60       4. Performed by a cluster node against another node that fails (by  the
61          fenced daemon).
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63       Unfencing
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65       1. libfence: unfence_node(), command line: fence_node -U nodename
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67       2. Turns on or enables a node.
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69       3. Agents run with the explicit action of "on" or "enable".
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71       4. Performed  by a cluster node "against" itself during startup (by the
72          cman init script).
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OPTIONS

76       -U     Unfence the node, default local node name.
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78       -S     Run status on node name.
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80       -m num Method number, starting from 1 (use with -S).
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82       -e 0|1 Enable/disable fenced_external notification.
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84       -v     Show fence agent results, -vv to also show agent args.
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86       -h     Print a help message describing available options, then exit.
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88       -V     Print program version information, then exit.
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FILES

92       The Unfencing/unfence_node() configuration is very similar to the Fenc‐
93       ing/fence_node()  configuration  shown in fenced(8).  Unfencing is only
94       performed for a node with an <unfence> section:
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96       <clusternode name="node1" nodeid="1">
97               <fence>
98               </fence>
99               <unfence>
100               </unfence>
101       </clusternode>
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103       The <unfence> section does  not  contain  <method>  sections  like  the
104       <fence>  section does.  It contains <device> references directly, which
105       mirror the corresponding device sections for <fence>, with the  notable
106       addition  of  the  explicit  action  of  "on"  or  "enable".   The same
107       <fencedevice> is referenced by both fence and unfence  <device>  lines,
108       and the same per-node args should be repeated.
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110       <clusternode name="node1" nodeid="1">
111               <fence>
112               <method name="1">
113               <device name="myswitch" foo="x"/>
114               </method>
115               </fence>
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117               <unfence>
118               <device name="myswitch" foo="x" action="on"/>
119               </unfence>
120       </clusternode>
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SEE ALSO

124       fenced(8)
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129cluster                           2009-12-21                     FENCE_NODE(8)
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