envd(1M) envd(1M)
NAME [Toc] [Back]
envd - system physical environment daemon
SYNOPSIS [Toc] [Back]
/usr/sbin/envd [-f configfile]
DESCRIPTION [Toc] [Back]
The envd daemon provides a means for the system to respond to
environmental conditions detected by hardware. Such responses are
typically designed to maintain file system integrity and prevent data
loss. The environmental conditions currently recognized by envd are
over-temperature and chassis fan failure.
envd logs messages and then executes actions when a supported
environmental event is detected. Whether to do message logging and
what actions to perform for a given environmental event are determined
by configfile (default is /etc/envd.conf). If no -f option was
specified and the default configfile /etc/envd.conf does not exist,
envd fails. A recommended default configfile is available in
/usr/newconfig/etc/envd.conf. The configfile (or /etc/envd.conf) is
only examined when the daemon is started or when it receives a SIGHUP
signal to restart and re-initialize the daemon itself.
envd uses the syslog message logging facility to log warning messages.
If configfile specifies messages to be logged, the destination of the
warning messages is determined by the configuration of the LOG_DAEMON
facility of the syslogd daemon (see syslogd(1M) and syslog(3C) for
details) and various syslog priorities defined below for the
corresponding environmental events. Warning messages are written to
the console if envd is unable to send to syslogd.
The configfile is composed of event lines, each of which followed by
zero or more action lines. Comment lines can be interspersed at any
point. No more than one event line can be specified for a given
event.
Event Event lines consist of an event keyword and a
message indicator, separated by a colon (:).
Valid event keywords are OVERTEMP_CRIT,
OVERTEMP_EMERG, FANFAIL_CRIT, and FANFAIL_EMERG.
Valid message indicators are y and n. An example
is OVERTEMP_EMERG:y, indicating that warning
messages are to be sent for the OVERTEMP_EMERG
event.
Event keywords must start in the first column, and
only one event and one message indicator are
allowed on a given line.
Action Action lines can consist of a sequence of any
valid /usr/bin/sh commands or pipelines. Lines
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from one event line to the next event line, or to
the end of the file, are part of the action lines
for the preceding event, and are passed intact to
the shell to execute upon detecting the event.
The action for an event can span across several
lines, but the syntax of every line must be
understood by /usr/bin/sh. There are no default
actions for any events if no action lines are
specified.
No parsing or syntax checking is performed on the
action lines; system administrators are
responsible for verifying the correctness of the
action syntax.
Comments Lines beginning with the # character in the first
column are comment lines, and all characters up to
the subsequent new-line character are ignored.
Blank lines are ignored as comment lines.
Here is an example /etc/envd.conf file:
# The example below configures envd to log the warning message and
# to rcp critical applications to a remote machine at OVERTEMP_CRIT
# or FANFAIL_CRIT. It configures envd to log emergency messages
# and to perform system shutdown at OVERTEMP_EMERG or FANFAIL_CRIT,
# in order to reserve data integrity.
OVERTEMP_CRIT:y
/usr/bin/rcp critical_appl_files \
remote_machine:/backup
OVERTEMP_EMERG:y
/usr/sbin/reboot -qh
FANFAIL_CRIT:y
/usr/bin/rcp critical_appl_files \
remote_machine:/backup
FANFAIL_EMERG:y
/usr/sbin/reboot -qh
Only users with appropriate privileges can invoke envd.
Over-temperature and Fan Failure Handling [Toc] [Back]
Over-temperature and fan failure handling is supported only on systems
equipped with appropriate sensing hardware. Over-temperature and fan
failure limits vary, depending on the hardware. Each system processor
defines its own thresholds for supported equipment combinations. The
table below shows temperature and fan failure states. For the
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temperature ranges and fan states specific to your system
configuration, refer to any of the following documents for your
system: Site Planning and Preparation Guide, Installation and
Configuration Guide, or Operator Handbook.
________________________________________________________________
|State | State Description |
|___________________|___________________________________________|
|NORMAL | Within normal operating temperature range |
| | |
|OVERTEMP_CRIT | Temperature has exceeded the normal |
| | operating range of the system, but is |
| | still within the operating limit of the |
| | hardware media. |
| | |
|OVERTEMP_EMERG | Temperature has exceeded the maximum |
| | specified operating limit of hardware |
| | media; power loss is imminent. A minimum |
| | of about 60 seconds is guaranteed between |
| | the OVERTEMP_MID state and the |
| | OVERTEMP_POWERLOSS (power loss) state. |
| | |
|OVERTEMP_POWERLOSS | Hardware will disconnect all power from |
| | all cards in the system chassis. |
| | |
|FAN_NORMAL | All chassis fans are operating normally. |
| | |
|FANFAIL_CRIT | One or more chassis fans have failed, but |
| | the system has enough redundant fans to |
| | allow continued operation while the |
| | failed fans are replaced. |
| | |
|FANFAIL_EMERG | Chassis fan failures prevent continued |
| | operation of the system; power loss is |
| | imminent. |
| | |
|FANFAIL_POWERLOSS | Hardware will disconnect all power from |
| | all cards in the system chassis. |
| | |
|___________________|___________________________________________|
The syslog priorities mapped to the environmental events are:
LOG_EMERG (for OVERTEMP_EMERG and FANFAIL_EMERG) and LOG_CRIT (for
OVERTEMP_CRIT and FANFAIL_CRIT).
Any non-shutdown activities (e.g. file transfer) should be performed
at OVERTEMP_CRIT and FANFAIL_CRIT. It is important to configure only
critical activities for OVERTEMP_CRIT because the over-temperature
might rise dramatically fast to OVERTEMP_EMERG. It is recommended to
perform a quick shutdown using /usr/sbin/reboot -qh at OVERTEMP_EMERG
and FANFAIL_EMERG to preserve file system data integrity. If the
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hardware enters the OVERTEMP_POWERLOSS or FANFAIL_POWERLOSS state and
the system has not been shut down, the sudden loss of power could
result in data loss. Note that power-fail recovery functionality is
not available in this case. When the hardware powers down, no warning
messages are produced, and no action is taken by the system.
Whenever an environmental state changes from one level to another
(such as from NORMAL to OVERTEMP_CRIT or from FANFAIL_CRIT to
FANFAIL_EMERG), the warning message, if specified, is logged, and the
corresponding action is executed once, and only once, per state
change.
AUTHOR [Toc] [Back]
envd was developed by HP.
FILES [Toc] [Back]
/usr/sbin/envd envd executable file
/etc/envd.conf default envd configuration file
/etc/syslog.conf default syslog configuration file
/var/tmp/envd.action[123] envd work files
SEE ALSO [Toc] [Back]
reboot(1M), shutdown(1M), syslogd(1M), syslog(3C).
HP-UX System Administration manuals.
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