The well-known plugin check_by_ssh is a wrapper around the ssh client program. Unfortunately the path to ssh is defined at compile-time and remains hard-coded in the check_by_ssh binary. Usually this is /usr/bin/ssh. If you want to use features which are not implemented in your distribution’s ssh, but in an alternative ssh binary, you have to recompile check_by_ssh. Here is a patch which makes it easy to switch between multiple ssh binaries using a command line parameter.
--- nagios-plugins-1.4.15.orig/plugins/check_by_ssh.c 2010-07-27 22:47:16.000000000 +0200
+++ nagios-plugins-1.4.15/plugins/check_by_ssh.c 2012-06-12 14:02:07.000000000 +0200
@@ -177,6 +177,7 @@
{"identity", required_argument, 0, 'i'},
{"user", required_argument, 0, 'u'},
{"logname", required_argument, 0, 'l'},
+ {"ssh-command", required_argument, 0, 'c'},
{"command", required_argument, 0, 'C'},
{"skip", optional_argument, 0, 'S'}, /* backwards compatibility */
{"skip-stdout", optional_argument, 0, 'S'},
@@ -277,6 +278,9 @@
case 'f': /* fork to background */
comm_append("-f");
break;
+ case 'c':
+ commargv[0] = strdup(optarg);
+ break;
case 'C': /* Command for remote machine */
commands++;
if (commands > 1)
@@ -404,6 +408,8 @@
printf (" %s\n", _("Ignore all or (if specified) first n lines on STDERR [optional]"));
printf (" %s\n", "-f");
printf (" %s\n", _("tells ssh to fork rather than create a tty [optional]. This will always return OK if ssh is executed"));
+ printf (" %s\n","-c, --ssh-command=COMMAND");
+ printf (" %s\n", _("execute an alternative ssh binary"));
printf (" %s\n","-C, --command='COMMAND STRING'");
printf (" %s\n", _("command to execute on the remote machine"));
printf (" %s\n","-l, --logname=USERNAME");Now you tell check_by_ssh to use a specific ssh client by setting the –ssh-command parameter.
/omd/sites/nagios_selftest/local/lib/nagios/plugins/check_by_ssh \
--host 10.178.26.19 --port 22 --logname nagios --timeout 60 \
--ssh-command /omd/sites/nagios_selftest/ssh/local/bin/ssh \
--ssh-option "ControlPath=/omd/sites/nagios_selftest/tmp/ssh/controlpath/ssh-%r@%h"
....(As far as i remember my distribution’s ssh did not handle the ControlMaster mechanism correctly, so i compiled my own openssh environment. That’s how this patch came into being)