NAME¶
pmdashping - "shell-ping" performance metrics domain agent
SYNOPSIS¶
$PCP_PMDAS_DIR/shping/pmdashping [
-C] [
-d domain]
[
-l logfile] [
-I interval] [
-t
timeout] [
-U username]
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.
- -U
- User account under which to run the agent and all commands. The default is
the unprivileged "pcp" account in current versions of PCP, but
in older versions the superuser account ("root") was used by
default.
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(5).
SEE ALSO¶
pmcd(1) and
pmgshping(1).