SYNOPSIS

xymond_channel --channel=page xymond_alert [options]

DESCRIPTION

xymond_alert is a worker module for xymond, and as such it is normally run via the xymond_channel(8) program. It receives xymond page- and ack-messages from the "page" channel via stdin, and uses these to send out alerts about failed and recovered hosts and services.

The operation of this module is controlled by the alerts.cfg(5) file. This file holds the definition of rules and recipients, that determine who gets alerts, how often, for what servers etc.

OPTIONS

--config=FILENAME

Sets the filename for the alerts.cfg file. The default value is "etc/alerts.cfg" below the Xymon server directory.

--dump-config

Dumps the configuration after parsing it. May be useful to track down problems with configuration file errors.

--checkpoint-file=FILENAME

File where the current state of the xymond_alert module is saved. When starting up, xymond_alert will also read this file to restore the previous state.

--checkpoint-interval=N

Defines how often (in seconds) the checkpoint-file is saved.

--cfid

If this option is present, alert messages will include a line with "cfid:N" where N is the linenumber in the alerts.cfg file that caused this message to be sent. This can be useful to track down problems with duplicate alerts.

--test HOST SERVICE [options]

Shows which alert rules matches the given HOST/SERVICE combination. Useful to debug configuration problems, and see what rules are used for an alert.

The possible options are:
--color=COLORNAME The COLORNAME parameter is the color of the alert: red, yellow or purple.
--duration=MINUTES The MINUTES parameter is the duration of the alert in minutes.
--group=GROUPNAME The GROUPNAME parameter is a groupid string from the analysis.cfg file.
--time=TIMESTRING The TIMESTRING parameter is the time-of-day for the alert, expressed as an absolute time in the epoch format (seconds since Jan 1 1970). This is easily obtained with the GNU date utility using the "+%s" output format.

--trace=FILENAME

Send trace output to FILENAME, This allows for more detailed analysis of how alerts trigger, without having the full debugging enabled.

--debug

Enable debugging output.

HOW XYMON DECIDES WHEN TO SEND ALERTS

The xymond_alert module is responsible for sending out all alerts. When a status first goes to one of the ALERTCOLORS, xymond_alert is notified of this change. It notes that the status is now in an alert state, and records the timestamp when this event started, and adds the alert to the list statuses that may potentially trigger one or more alert messages.

This list is then matched against the alerts.cfg configuration. This happens at least once a minute, but may happen more often. E.g. when status first goes into an alert state, this will always trigger the matching to happen.

When scanning the configuration, xymond_alert looks at all of the configuration rules. It also checks the DURATION setting against how long time has elapsed since the event started - i.e. against the timestamp logged when xymond_alert first heard of this event.

When an alert recipient is found, the alert is sent and it is recorded when this recipient is due for his next alert message, based on the REPEAT setting defined for this recipient. The next time xymond_alert scans the configuration for what alerts to send, it will still find this recipient because all of the configuration rules are fulfilled, but an alert message will not be generated until the repeat interval has elapsed.

It can happen that a status first goes yellow and triggers an alert, and later it goes red - e.g. a disk filling up. In that case, xymond_alert clears the internal timer for when the next (repeat) alert is due for all recipients. You generally want to be told when something that has been in a warning state becomes critical, so in that case the REPEAT setting is ignored and the alert is sent. This only happens the first time such a change occurs - if the status switches between yellow and red multiple times, only the first transition from yellow->red causes this override.

When an status recovers, a recovery message may be sent - depending on the configuration - and then xymond_alert forgets everything about this status. So the next time it goes into an alert state, the entire process starts all over again.

FILES

~xymon/server/etc/alerts.cfg