envd(1M) Series 800 Only

NAME

envd − system physical environment daemon

SYNOPSIS

/etc/envd [−f configfile]

DESCRIPTION

The envd daemon provides a means for the system to respond to undesirable environmental conditions detected by hardware. Such responses are typically designed to maintain file system integrity and prevent data loss. The only environmental condition recognized by the current version of envd is over-temperature.

envd uses the syslog message logging facility to log warning messages resulting from environmental events, sending the messages to configurable destinations. envd also executes predetermined default actions or those specified in configfile (default is /etc/envd.conf). envd warning messages can be configured with the LOG_DAEMON facility (see syslogd(1M) and syslog(3C) for details) and various syslog priorities defined below for corresponding events.

Lines in configfile are interpreted as event lines, action lines, or comment lines:

Event It contains two fields, event keyword and message toggle, with column (:) as the separator. Valid event keywords are OVERTEMP_CRIT and OVERTEMP_EMERG. Valid message_toggle keywords are msg_on and msg_off. An example is: OVERTEMP_EMERG:msg_on. Event keywords must start in the first column, and only one event and one message-toggle keyword is allowed on a given line.

Action Action lines can consist of a sequence of any valid /bin/sh commands or pipelines. Any number of spaces or tabs can be placed at the beginning of action lines. All text from one event keyword up to the next event keyword are part of the action for the preceding event keyword. The action for an event can span across several lines, but the syntax of every line must be understood by /bin/sh.

Action lines consisting of an empty string are interpreted as a no-op. 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.

An example of the /etc/envd.conf file

    # Configuration file for the envd to handle environment
    # event, such as over-temperature. The syntax is:
    #
    # Event:message_toggle
    #   Action
    #
    # Two valid event keywords are OVERTEMP_CRIT and
    # OVERTEMP_EMERG.

    # The next four lines configure envd to rcp my
    # working files onto the remote machine watchdog
    # at OVERTEMP_CRIT and perform system shutdown.
    # The msg_on will cause warning messages to be sent.
    #
    OVERTEMP_CRIT:msg_on
/usr/bin/rcp my_working_files \
             remote_watchdog_system:/my_dir/backupdir
        shutdown

The syslog priorities mapped to two environment events are: LOG_EMERG (for OVERTEMP_EMERG) and LOG_CRIT (for OVERTEMP_CRIT). Warning messages are written to the console if envd is unable to send to syslogd.

Only a user with appropriate privileges can invoke envd. envd creates the file /etc/envd.pid, if possible, containing a single line with its process ID. This can be used to kill or reconfigure envd by sending a SIGTERM or SIGHUP signal.

Over-temperature Handling

Over-temperature handling is supported only on systems equipped with over-temperature sensing hardware. Over-temperature limits may vary, depending on the hardware. Each system processor defines its own safest threshold for supported equipment combinations. The table below shows four levels of temperature states. For the temperature range specific to your system configuration, refer to the Site Planning and Preparation Guide for your system.

State	State Description
NORMAL	Within normal operating temperature range
OVERTEMP_CRIT	Temperature has exceed the normal operating range of the system, but it 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.
OVERTEMP_POWERLESS	Hardware will disconnect all power from all cards in the system processor; a minimum of about 60 seconds is guaranteed between entering the OVERTEMP_EMERG state and power loss.

The default action for OVERTEMP_EMERG is system shut down with

sync; sync; /etc/reboot -q.

There is no default action for OVERTEMP_CRIT .

Any non-shutdown activities (e.g. file transfer) should be performed at OVERTEMP_CRIT, and system shutdown at OVERTEMP_EMERG to preserve file system data integrity. If the hardware enters the OVERTEMP_POWERLESS state and the system has not been shutdown, the sudden loss of power could result in data loss. Note that power-fail recovery functionality is available in this case. When the hardware powers down, no warning messages are produced, and no action is taken by the system.

Whenever the temperature rises from one level to another (such as from NORMAL to OVERTEMP_CRIT or from OVERTEMP_CRIT to OVERTEMP_EMERG, the corresponding specified over-temperature action is executed once and only once per state change. The warning message, however, is still sent periodically if the temperature condition is not remedied. When over-temperature conditions are corrected back to NORMAL, no warning messages are sent.

Refer to shutdown(1M) and reboot(1M) for the effect of reboot or shutdown in the HP Clustered environment.

AUTHOR

envd was developed by HP.

FILES

/etc/envd envd executable file

/etc/envd.conf default envd configuration file

/etc/syslog.conf default syslog configuration file

/etc/envd.pid process ID of envd

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