/ 
psmon-1.006
River stage zero No dependents
/ psmon

NAME

psmon - Process Table Monitoring Script

VERSION

$Id: psmon,v 1.6 2004/08/01 10:43:07 nicolaw Exp $

SYNOPSIS

Single user account crontab operation.

# DO NOT EDIT THIS FILE - edit the master and reinstall.
# (/tmp/crontab.28945 installed on Wed Jan  8 16:29:24 2003)
# (Cron version -- $Id: psmon,v 1.6 2004/08/01 10:43:07 nicolaw Exp $)
MAILTO="nicolaworthington@msn.com"
USER=nicolaw
 
*/5 * * * *    /sbin/psmon --daemon --cron --conf=~/etc/psmon.conf --user=$USER --adminemail=nicolaworthington@msn.com

Regular system-wide call from cron:

*/5 * * * *    /sbin/psmon --daemon --cron

Only check processes during working office hours:

* 9-17 * * *   /sbin/psmon

Command line syntax.

[nicolaw@nicolaw]$ psmon --help
Syntax: psmon [--conf=filename] [--daemon] [--cron] [--user=user]
              [--adminemail=emailaddress] [--dryrun] [--help] [--version]
   --help            Display this help
   --version         Display full version information
   --dryrun          Dryrun (do not actually kill or spawn and processes)
   --daemon          Spawn in to background daemon
   --cron            Disables 'already running' errors with the --daemon option
   --conf=str        Specify alternative config filename
   --user=str        Only scan the process table for processes running as str
   --adminemail=str  Force all notification emails to be sent to str

DESCRIPTION

This script monitors the process table using Proc::ProcessTable, and will respawn or kill processes based on a set of rules defined in an Apache style configuration file.

Processes will be respawned if a spawn command is defined for a process, and no occurances of that process are running. If the --user command line option is specified, then the process will only be spawned if no instances are running as the specified userid.

Processes can be killed off if they have been running for too long, use too much CPU or memory resources, or have too many concurrent versions running. Exceptions can be made to kill rulesets using the pidfile and lastsafepid directives.

If a PID file is declared for a process, psmon will never kill the process ID that is contained within the pid file. This is useful if for example, you have a script which spawns hundreds of child processes which you may need to automatically kill, but you do not want to kill the parent process.

Any actions performed will be logged to the DAEMON syslog facility by default. There is support to optionally also send notifications emails to an administrator on a global or pre-rule basis.

OPERATION

--dryrun

Execute a dry-run (do not actually kill or spawn and processes).

--conf=filename

Specify alternative config filename.

--daemon

Spawn in to background daemon.

--cron

Disables already running warnings when trying to launch as another daemon.

--user=user

Only scan the process table for processes running under this username.

--adminemail=emailaddress

Force all notification emails to be sent to this email address.

INSTALLATION

In addition to Perl 5.005_03 or higher, the following Perl modules are required:

Getopt::Long
Config::General
POSIX
Proc::ProcessTable
Net::SMTP
Unix::Syslog

The POSIX module is usually supplied with Perl as standard, as is Getopt::Long. All these modules can be obtained from CPAN. Visit http://search.span.org and http://www.cpan.org for further details. For the lazy people reading this, you can try the following command to install these modules:

    for m in Getopt::Long Config::General POSIX Proc::ProcessTable \
	 Net::SMTP Unix::Syslog;do perl -MCPAN -e"install $m";done

Alternatively you can run the install.sh script which comes in the distribution tarball. It will attempt to install the right modules, install the script and configuration file, and generate UNIX man page documentation.

By default psmon will look for its runtime configuration in /etc/psmon.conf, although this can be defined as otherwise from the command line. For system wide installations it is reccomended that you install your psmon in to the default location.

CONFIGURATION

The default configuration file location is /etc/psmon.conf. A different configuration file can be declared from the command line.

Syntax of the configuration file is based upon that which is used by Apache. Each process to be monitored is declared with a Process scope directive like this example which monitors the OpenSSH daemon:

<Process sshd>
    spawncmd    /sbin/service sshd start
    pidfile     /var/run/sshd.pid
    instances   50
    pctcpu      90
</Process>

There is a special * process scope which applies to all running processes. This special scope should be used with extreme care. It does not support the use of the spawncmd, pidfile, instances or ttl directivers. A typical example of this scope might be as follows:

<Process *>
    pctcpu    95
    pctmem    80
</Process>

Global directives which are not specific to any one process should be placed outside of any Process scopes.

DIRECTIVES

Facility

Defines which syslog facility to log to. Valid options are as follows; LOG_KERN, LOG_USER, LOG_MAIL, LOG_DAEMON, LOG_AUTH, LOG_SYSLOG, LOG_LPR, LOG_NEWS, LOG_UUCP, LOG_CRON, LOG_LOCAL0, LOG_LOCAL1, LOG_LOCAL2, LOG_LOCAL3, LOG_LOCAL4, LOG_LOCAL5, LOG_LOCAL6 and LOG_LOCAL7. Defaults to LOG_DAEMON.

LogLevel

Defines the loglevel priority that notifications to syslog will be marked as. Valid options are as follows; LOG_EMERG, LOG_ALERT, LOG_CRIT, LOG_ERR, LOG_WARNING, LOG_NOTICE, LOG_INFO and LOG_DEBUG. The log level used by a notification for any failed action will automatically be raised to the next level in order to highlight the failure. May be also be used in a Process scope which will take priority over a global declaration. Defaults to LOG_NOTICE.

KillLogLevel (previously KillPIDLogLevel)

The same as the loglevel directive, but only applies to process kill actions. Takes priority over the loglevel directive. May be also be used in a Process scope which will take priority over a global declaration. Undefined by default.

SpawnLogLevel

The same as the loglevel directive, but only applies to process spawn actions. Takes priority over the loglevel directive. May be also be used in a Process scope which will take priority over a global declaration. Undefined by default.

AdminEmail

Defines the email address where notification emails should be sent to. May be also be used in a Process scope which will take priority over a global declaration. Defaults to root@localhost.

NotifyEmailFrom

Defines the email address that notification email should be addresses from. Defaults to <username>@hostname.

Frequency

Defines the frequency of process table queries. Defaults to 60 seconds.

LastSafePID

When defined, psmon will never attempt to kill a process ID which is numerically less than or equal to the value defined by lastsafepid. It should be noted that psmon will never attempt to kill itself, or a process ID less than or equal to 1. Defaults to 100.

ProtectSafePIDsQuietly

Accepts a boolean value of On or Off. Surpresses all notifications of preserved process IDs when used in conjunction with the lastsafepid directive. Defaults to Off.

SMTPHost

Defines the IP address or hostname of the SMTP server to used to send email notifications. Defaults to localhost.

SMTPTimeout

Defines the timeout in seconds to be used during SMTP connections. Defaults to 20 seconds.

SendmailCmd

Defines the sendmail command to use to send notification emails if there is a failure with the SMTP connection to the host defined by smtphost. Defaults to '/usr/sbin/sendmail -t'.

Dryrun

Forces this psmon to as if the --dryrun command line switch had specified. This is useful if you want to force a specific configuration file to only report and never actually take any automated action.

NotifyDetail

Defines the verbosity of notification emails which are sent. Can be set to 'Simple', 'Verbose' or 'Debug'. Defaults to 'Verbose'. This function will be removed soon. It is unnecessary bloat and is not very portable.

PROCESS SCOPE DIRECTIVES

SpawnCmd

Defines the full command line to be executed in order to respawn a dead process.

KillCmd

Defines the full command line to be executed in order to gracefully shutdown or kill a rogue process. If the command returns a boolean true exit status then it is assumed that the command failed to execute sucessfully. If no KillCmd is specified or the command fails, the process will be killed by sending a SIGKILL signal with the standard kill() function. Undefined by default.

PIDFile

Defines the full path and filename of a file created by a process which contain it's main parent process ID.

TTL

Defines a maximum time to live (in seconds) of a process. The process will be killed once it has been running longer than this value, and it's process ID isn't contained in the defined pidfile.

PctCpu

Defines a maximum allowable percentage of CPU time a process may use. The process will be killed once it's CPU usage exceeds this threshold and it's process ID isn't contained in the defined pidfile.

PctMem

Defines a maximum allowable percentage of total system memory a process may use. The process will be killed once it's memory usage exceeds this threshold and it's process ID isn't contained in the defined pidfile.

Instances

Defines a maximum number of instances of a process which may run. The process will be killed once there are more than this number of occurances running, and it's process ID isn't contained in the defined pid file.

NoEmailOnKill

Accepts a boolean value of True or False. Surpresses process killing notification emails for this process scope. Defaults to False.

NoEmailOnSpawn

Accepts a boolean value of True or False. Surpresses process spawning notification emails for this process scope. Defaults to False.

NoEmail

Accepts a boolean value of True or False. Surpresses all notification emails for this process scope. Defaults to False.

NeverKillPID

Accepts a space delimited list of PIDs which will never be killed. Defaults to 1.

NeverKillProcessName

Accepts a space deliomited list of process names which will never be killed. Defaults to 'kswapd kupdated mdrecoveryd'.

EXAMPLES

<Process syslogd>
    spawncmd       /sbin/service syslogd restart
    pidfile        /var/run/syslogd.pid
    instances      1
    pctcpu         70
    pctmem         30
</Process>

Syslog is a good example of a process which can get a little full of itself under certian circumstances, and excessively hog CPU and memory. Here we will kill off syslogd processes if it exceeds 70% CPU or 30% memory utilization.

Older running copies of syslogd will be killed if they are running, while leaving the most recently spawned copy which will be listed in the PID file defined.

<Process httpd>
    spawncmd      /sbin/service httpd restart
    pidfile       /var/run/httpd.pid
    loglevel      critical
    adminemail    pager@noc.company.com
</Process>

Here we are monitoring Apache to ensure that it is restarted if it dies. The pidfile directive in this example is actually redundant because we have not defined any rule where we should consider killing any httpd processes.

All notifications relating to this process will be logged with the syslog priority of critical (LOG_CRIT), and all emailed to pager@noc.company.com which could typically forward to a pager.

Any failed attempts to kill or restart a process will automatically be logged as a syslog priority one level higher than that specified. If a restart of Apache were to fail in this example, a wall notification would be broadcast to all interactive terminals connected to the machine, since the next log priority up from LOG_CRIT is LOG_EMERG.

<Process find>
    noemail    True
    ttl        3600
</Process>

Kill old find processes which have been running for over an hour. Do not send an email notification since it's not too important.

SIGNALS

HUP

Forces an immediate reload of the configuration file. You should send the HUP signal when you are running psmon as a background daemon and have altered the psmon.conf file.

USR1

Forces an immediate scan of the process table.

EXIT CODES

Value 0: Exited gracefully

The program exited gracefully.

Value 2: Failure to lookup UID for username

The username specified by the --user command line option did not resolve to a valid UID.

Value 3: Configuration file is disabled

The configuration file is disabled. (It contains an active 'Disabled' directive).

Value 4: Configuration file does not exist

The specified configuration file, (default or user specified) does not exist.

Value 5: Unable to open PID file handle

Failed to open a read-only file handle for the runtime PID file.

Value 6: Failed to fork

An error occured while attempting to fork the child background daemon process.

Value 7: Unable to open PID file handle

Failed to open a write file handle for the runtime PID file.

Value 8: Failure to load Perl module

One or more Perl module could not be loaded. This usually happens when one of the required Perl modules which psmon depends upon is not installed or could not be located in the Perl LIB search path.

PERFORMANCE

psmon is not especially fast. Much of it's time is spent reading the process table. If the process table is particularly large this can take a number of seconds. Although is rarely a major problem on todays speedy machines, I have run a few tests so you take look at the times and decide if you can afford the wait.

CPU             OS              Open Files/Procs    1m Load    Real Time
PIII 1.1G       Mandrake 9.0         10148 / 267       0.01     0m0.430s
PIII 1.2G       Mandrake 9.0         16714 / 304       0.44     0m0.640s
Celeron 500     Red Hat 6.1           1780 /  81       1.27     0m0.880s
PII 450         Red Hat 6.0            300 /  23       0.01     0m1.050s
2x Xeon 1.8G    Mandrake 9.0         90530 / 750       0.38     0m1.130s
Celeron 500     Red Hat 6.1           1517 /  77       1.00     0m1.450s
PIII 866        Red Hat 8.0           3769 /  76       0.63     0m1.662s
PIII 750        Red Hat 6.2            754 /  35       3.50     0m2.170s

(Figures are accurate as of release 1.0.3).

These production machines were running the latest patched stock distribution kernels. I have listed the total number of open file descriptors, processes running and 1 minute load average to give you a slightly better context of the performance.

SUBROUTINES

check_processtable()

Reads the current process table, checks and then executes any appropriate action to be taken. Does not accept any paramaters.

slay_process()

Attempts to kill a process with it's killcmd, or failing that using the kill() function. Accepts the process name, syslog log level, email notification to address and a reference to the %slay hash.

Prints a Red Hat sysvinit style status message. Accepts an array of messages to display in sequence.

spawn_process()

Attempts to spawn a process. Accepts the process name, syslog log level, mail notification to address and spawn command.

display_help()

Displays command line help.

read_config()

Reads in runtime configuration options.

isnumeric()

An evil bastard fudge to ensure that we're only dealing with numerics when necessary, from the config file and Proc::ProcessTable scan.

loglevel()

Accepts a syslog loglevel keyword and returns the associated constant integer.

logfacility()

Accepts a syslog facility keyword and returns the associated constant integer.

alert()

Logs a message to syslog using log() and sends a notification email using sendmail().

log()

Logs messages to DAEMON facility in syslog. Accepts a log level and message array. Will terminate the process if it is asked to log a message of a log level 2 or less (LOG_EMERG, LOG_ALERT, LOG_CRIT).

sendmail()

Sends email notifications of syslog messages, called by alert(). Accepts sending email address, recipient email address, short message subject and an optional detailed message body array.

daemonize()

Launches the process in to the background. Checks to see if there is already an instance running.

display_version()

Displays complete version, author and license information.

BUGS

Hopefully none. ;-) Send any bug reports to me at nicolaworthington@msn.com along with any patches and details of how to replicate the problem. Please only send reports for bugs which can be replicated in the latest version of the software. The latest version can always be found at http://www.nicolaworthington.com

TODO

The following functionality will be added soon:

Code cleanup

The code needs to be cleaned up and made more efficient.

killperprocessname directive

Will accept a boolean value. If true, only 1 process per process scope will ever be killed, instead of all process IDs matching kill rules. This should be used in conjunction with the new killcmd directive. For example, you may define that a database daemon may never take up more than 90% CPU time, and it runs many children processes. If it exceeds 90% CPU time, you want to issue ONE restart command in order to stop and then start all the database processes in one go.

time period limited rules

Functionality to limit validity of process scopes to only be checked between defined time periods. For example, only check that httpd is running between the hours of 8am and 5pm on Mondays and Tuesdays.

SEE ALSO

nsmon

LICENSE

Written by Nicola Worthington, <nicolaworthington@msn.com>. Copyright (C) 2002,2003,2004 Nicola Worthington.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

AUTHOR

Nicola Worthington <nicolaworthington@msn.com>

http://www.nicolaworthington.com