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authorLennart Poettering <lennart@poettering.net>2012-04-05 22:08:10 +0200
committerLennart Poettering <lennart@poettering.net>2012-04-05 22:15:29 +0200
commite96d6be763014be75d480fde503d0b77f41194a0 (patch)
tree1bc3753e708c8b588c43ccd5b5c52c0adefc01c9 /man/systemd.conf.xml
parent348e27fedfd4cdd2238ff31a46785a70b9dc6fc0 (diff)
systemd: add hardware watchdog support
This adds minimal hardware watchdog support to PID 1. The idea is that PID 1 supervises and watchdogs system services, while the hardware watchdog is used to supervise PID 1. This adds two hardware watchdog configuration options, for the runtime watchdog and for a shutdown watchdog. The former is active during normal operation, the latter only at reboots to ensure that if a clean reboot times out we reboot nonetheless. If the runtime watchdog is enabled PID 1 will automatically wake up at half the configured interval and write to the watchdog daemon. By default we enable the shutdown watchdog, but leave the runtime watchdog disabled in order not to break independent hardware watchdog daemons people might be using. This is only the most basic hookup. If necessary we can later on hook up the watchdog ping more closely with services deemed crucial.
Diffstat (limited to 'man/systemd.conf.xml')
-rw-r--r--man/systemd.conf.xml45
1 files changed, 45 insertions, 0 deletions
diff --git a/man/systemd.conf.xml b/man/systemd.conf.xml
index ba144da8cf..c7890287b5 100644
--- a/man/systemd.conf.xml
+++ b/man/systemd.conf.xml
@@ -149,6 +149,51 @@
controllers in separate
hierarchies.</para></listitem>
</varlistentry>
+
+ <varlistentry>
+ <term><varname>RuntimeWatchdogSec=</varname></term>
+ <term><varname>ShutdownWatchdogSec=</varname></term>
+
+ <listitem><para>Configure the hardware
+ watchdog at runtime and at
+ reboot. Takes a timeout value in
+ seconds (or in other time units if
+ suffixed with <literal>ms</literal>,
+ <literal>min</literal>,
+ <literal>h</literal>,
+ <literal>d</literal>,
+ <literal>w</literal>). If
+ <varname>RuntimeWatchdogSec=</varname>
+ is set to a non-zero value the
+ watchdog hardware
+ (<filename>/dev/watchdog</filename>)
+ will be programmed to automatically
+ reboot the system if it is not
+ contacted within the specified timeout
+ interval. The system manager will
+ ensure to contact it at least once in
+ half the specified timeout
+ interval. This feature requires a
+ hardware watchdog device to be
+ present, as it is commonly the case in
+ embedded and server systems. Not all
+ hardware watchdogs allow configuration
+ of the reboot timeout, in which case
+ the closest available timeout is
+ picked. <varname>ShutdownWatchdogSec=</varname>
+ may be used to configure the hardware
+ watchdog when the system is asked to
+ reboot. It works as a safety net to
+ ensure that the reboot takes place
+ even if a clean reboot attempt times
+ out. By default
+ <varname>RuntimeWatchdogSec=</varname>
+ defaults to 0 (off), and
+ <varname>ShutdownWatchdogSec=</varname>
+ to 10min. These settings have no
+ effect if a hardware watchdog is not
+ available.</para></listitem>
+ </varlistentry>
</variablelist>
</refsect1>