Chapter 4. Using Pacemaker Tools
In the dark past, configuring Pacemaker required the administrator to read and write XML. In true UNIX style, there were also a number of different commands that specialized in different aspects of querying and updating the cluster.
Since Pacemaker 1.0, this has all changed and we have an integrated, scriptable, cluster shell that hides all the messy XML scaffolding. It even allows you to queue up several changes at once and commit them atomically.
Take some time to familiarize yourself with what it can do.
[root@pcmk-1 ~]# crm --help
usage:
crm [-D display_type]
crm [-D display_type] args
crm [-D display_type] [-f file]
Use crm without arguments for an interactive session.
Supply one or more arguments for a "single-shot" use.
Specify with -f a file which contains a script. Use '-' for
standard input or use pipe/redirection.
crm displays cli format configurations using a color scheme
and/or in uppercase. Pick one of "color" or "uppercase", or
use "-D color,uppercase" if you want colorful uppercase.
Get plain output by "-D plain". The default may be set in
user preferences (options).
Examples:
# crm -f stopapp2.cli
# crm < stopapp2.cli
# crm resource stop global_www
# crm status
The primary tool for monitoring the status of the cluster is crm_mon (also available as crm status). It can be run in a variety of modes and has a number of output options. To find out about any of the tools that come with Pacemaker, simply invoke them with the --help
option or consult the included man pages. Both sets of output are created from the tool, and so will always be in sync with each other and the tool itself.
Additionally, the Pacemaker version and supported cluster stack(s) is available via the --version
option.
[root@pcmk-1 ~]# crm_mon --version
crm_mon 1.0.5 for OpenAIS and Heartbeat (Build: 462f1569a43740667daf7b0f6b521742e9eb8fa7)
Written by Andrew Beekhof
[root@pcmk-1 ~]# crm_mon --help
crm_mon - Provides a summary of cluster's current state.
Outputs varying levels of detail in a number of different formats.
Usage: crm_mon mode [options]
Options:
-?, --help This text
-$, --version Version information
-V, --verbose Increase debug output
Modes:
-h, --as-html=value Write cluster status to the named file
-w, --web-cgi Web mode with output suitable for cgi
-s, --simple-status Display the cluster status once as a simple one line output (suitable for nagios)
-S, --snmp-traps=value Send SNMP traps to this station
-T, --mail-to=value Send Mail alerts to this user. See also --mail-from, --mail-host, --mail-prefix
Display Options:
-n, --group-by-node Group resources by node
-r, --inactive Display inactive resources
-f, --failcounts Display resource fail counts
-o, --operations Display resource operation history
-t, --timing-details Display resource operation history with timing details
Additional Options:
-i, --interval=value Update frequency in seconds
-1, --one-shot Display the cluster status once on the console and exit
-N, --disable-ncurses Disable the use of ncurses
-d, --daemonize Run in the background as a daemon
-p, --pid-file=value (Advanced) Daemon pid file location
-F, --mail-from=value Mail alerts should come from the named user
-H, --mail-host=value Mail alerts should be sent via the named host
-P, --mail-prefix=value Subjects for mail alerts should start with this string
-E, --external-agent=value A program to run when resource operations take place.
-e, --external-recipient=value A recipient for your program (assuming you want the program to send something to someone).
Examples:
Display the cluster´s status on the console with updates as they occur:
# crm_mon
Display the cluster´s status on the console just once then exit:
# crm_mon
Display your cluster´s status, group resources by node, and include inactive resources in the list:
# crm_mon --group-by-node --inactive
Start crm_mon as a background daemon and have it write the cluster´s status to an HTML file:
# crm_mon --daemonize --as-html /path/to/docroot/filename.html
Start crm_mon as a background daemon and have it send email alerts:
# crm_mon --daemonize --mail-to user@example.com --mail-host mail.example.com
Start crm_mon as a background daemon and have it send SNMP alerts:
# crm_mon --daemonize --snmp-traps snmptrapd.example.com
Report bugs to pacemaker@oss.clusterlabs.org
Note
If the SNMP and/or email options are not listed, then Pacemaker was not built to support them. This may be by the choice of your distribution or the required libraries may not have been available. Please contact whoever supplied you with the packages for more details.