NAME
pmdashping - "shell-ping" performance metrics domain agent
SYNOPSIS
$PCP_PMDAS_DIR/shping/pmdashping [-C] [-d domain] [-l logfile] [-I
interval] [-t timeout] configfile
DESCRIPTION
pmdashping is a Performance Metrics Domain Agent (PMDA) which exports
quality of service and response time measurements for arbitrary
commands as might be run from a shell such as sh(1).
These measurements are intended to be used to quantify service quality
and service availability for those services that are either mission
critical or act as early indicators of adverse system performance.
The sample configuration monitors simple shell commands (exit and
date(1)), a short computationally intensive task using sum(1), a short
C compilation, DNS lookup via nslookup(1), YP lookup via ypcat(1),
bind/portmapper service using rpcbind(1), SMTP by connecting to telnet
port 25 and sending an ‘‘expn root’’ request, and NNTP by connecting to
telnet port 119 and running a ‘‘listgroup’’ command.
It is expected that other commands would follow the examples in the
sample configuration file, and most deployments of the pmdashping PMDA
are expected to use a customized configuration file.
A brief description of the pmdashping command line options follows:
-C Parse configfile, reporting any errors and exiting with non-zero
status if the file contains syntactical errors.
-d It is absolutely crucial that the performance metrics domain
number specified here is unique and consistent. That is, domain
should be different for every PMDA on the one host, and the same
domain number should be used for the same PMDA on all hosts.
-l Location of the log file. By default, a log file named shping.log
is written in the current directory of pmcd(1) when pmdashping is
started, i.e. $PCP_LOG_DIR/pmcd. If the log file cannot be
created or is not writable, output is written to the standard
error instead.
-I Amount of time (in seconds) between subsequent executions of the
list of commands provided via the configuration file configfile.
The default is 2 minutes.
-t Amount of time (in seconds) to wait before timing out awaiting a
response for a command from configfile. The default is 20
seconds.
The required configfile specifies ‘‘tag’’ and ‘‘command’’ pairs, each
on a separate line. All of the commands are run one after another,
with the whole group rescheduled to be run once per interval. For each
command that is run, pmdashping records information related to the
success (or timeout), exit status, elapsed time and CPU time (system
and user), and this information is exported by the PMDA. The tags are
used to identify the individual commands amongst the values exported by
the PMDA, and form the external instance domain identifiers for the
pmdashping metrics which relate to each command.
INSTALLATION
In order for a host to export the names, help text and values for the
shping performance metrics, do the following as root:
# cd $PCP_PMDAS_DIR/shping
# ./Install
The set of ‘‘tag’’ and ‘‘command’’ pairs may be specified from a
default (sample) configuration file, a customized file or entered
interactively as part of the Install script.
If you want to undo the installation, do the following as root:
# cd $PCP_PMDAS_DIR/shping
# ./Remove
pmdashping is launched by pmcd(1) and should never be executed
directly. The Install and Remove scripts notify pmcd(1) when the agent
is installed or removed.
FILES
$PCP_PMCDCONF_PATH
command line options used to launch pmdashping
$PCP_PMDAS_DIR/shping/help
default help text file for the shping metrics
$PCP_PMDAS_DIR/shping/sample.conf
example configuration file with a number of common commands
$PCP_PMDAS_DIR/shping/Install
installation script for the pmdashping agent
$PCP_PMDAS_DIR/shping/Remove
undo installation script for pmdashping
$PCP_LOG_DIR/pmcd/shping.log
default log file for error messages and other information
from pmdashping
PCP ENVIRONMENT
Environment variables with the prefix PCP_ are used to parameterize the
file and directory names used by PCP. On each installation, the file
/etc/pcp.conf contains the local values for these variables. The
$PCP_CONF variable may be used to specify an alternative configuration
file, as described in pcp.conf(4).
SEE ALSO
pmcd(1) and pmgshping(1).