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3 <!-- Fill in your name for FIRSTNAME and SURNAME. -->
4 <!-- Please adjust the date whenever revising the manpage. -->
5 <!ENTITY dhdate "<date>June 08, 2010</date>">
6 <!-- SECTION should be 1-8, maybe w/ subsection other parameters are
7 allowed: see man(7), man(1). -->
8 <!ENTITY dhsection "<manvolnum>8</manvolnum>">
9 <!ENTITY dhucpackage "<refentrytitle>ganeti-watcher</refentrytitle>">
10 <!ENTITY dhpackage "ganeti-watcher">
12 <!ENTITY debian "<productname>Debian</productname>">
13 <!ENTITY gnu "<acronym>GNU</acronym>">
14 <!ENTITY gpl "&gnu; <acronym>GPL</acronym>">
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25 <holder>Google Inc.</holder>
33 <refmiscinfo>Ganeti 2.2</refmiscinfo>
36 <refname>&dhpackage;</refname>
38 <refpurpose>Ganeti cluster watcher</refpurpose>
42 <command>&dhpackage; </command>
47 <title>DESCRIPTION</title>
50 The <command>&dhpackage;</command> is a periodically run script
51 which is responsible for keeping the instances in the correct
52 status. It has two separate functions, one for the master node
53 and another one that runs on every node.
57 <title>Master operations</title>
60 Its primary function is to try to keep running all instances
61 which are marked as <emphasis>up</emphasis> in the configuration
62 file, by trying to start them a limited number of times.
66 Its other function is to <quote>repair</quote> DRBD links by
67 reactivating the block devices of instances which have
68 secondaries on nodes that have been rebooted.
75 <title>Node operations</title>
78 The watcher will restart any down daemons that are appropriate
83 In addition, it will execute any scripts which exist under the
84 <quote>watcher</quote> directory in the Ganeti hooks directory
85 (@SYSCONFDIR@/ganeti/hooks). This should be used for
86 lightweight actions, like starting any extra daemons.
91 parameter <literal>maintain_node_health</literal> is enabled,
92 then the watcher will also shutdown instances and DRBD devices
93 if the node is declared as offline by known master candidates.
97 The watcher does synchronous queries but will submit jobs for
98 executing the changes. Due to locking, it could be that the jobs
99 execute much later than the watcher executes them.
111 The command has a state file located at
112 <filename>@LOCALSTATEDIR@/lib/ganeti/watcher.data</filename>
113 (only used on the master) and a log file at
114 <filename>@LOCALSTATEDIR@/log/ganeti/watcher.log</filename>. Removal of
115 either file will not affect correct operation; the removal of
116 the state file will just cause the restart counters for the
117 instances to reset to zero.
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