README

This repository contains scripts to facilitate monitoring Erlang. systems using the Nagios monitoring framework.

At this time it supports monitoring nodes, applications and process groups.

Files

README - this file
Makefile - build script
check_erlang_application.sh - shell script interface to check erlang apps are running
check_erlang_node.sh - shell script interface to check erlang node is running
check_erlang_pg.sh - shell script interface to check process group is running
nagios_erlang.erl - Erlang implementation of checking apps/nodes/pgs
ebin/ - contains compiled Erlang files

Command Line Usage Examples

Examples of running the verification scripts directly (not via Nagios). These scripts are all being run in a Git checkout of the code, and after running make within that directory.

To run in other directorys, the --beam parameter will need to be updated to point to the directory where nagios_erlang.beam can be found.

Checking Nodes

bash-3.2$ ./check_erlang_node.sh -e `which erl` -n my_node -c `cat /path/to/.erlang.cookie`
OK - Node my_node running.

Checking Applications

bash-3.2$ ./check_erlang_application.sh -e `which erl` -n my_node -c `cat /path/to/.erlang.cookie` -a application1,application2
OK - Applications ["application1","application2"] running on Node my_node.

Checking Process Groups

./check_erlang_pg.sh -e /usr/bin/erl -n my_node -p my_group -w 1
OK - Process group my_group populated on Node my_node with 3 processes.

Full Example

First, we check that the node doesn't exist before we start it:

bash-3.2$ ./check_erlang_node.sh -e erl -n my_node@`hostname` -c cookie
CRITICAL - Node 'my_node@will-larsons-macbook.local' not running.

Next, actually start the node:

will-larsons-macbook:~ lethain$ erl -setcookie cookie -name my_node@`hostname`
Erlang R13B03 (erts-5.7.4) [source] [smp:2:2] [rq:2] [async-threads:0] [hipe] [kernel-poll:false]
Eshell V5.7.4  (abort with ^G)
(my_node@will-larsons-macbook.local)1> node().
'my_node@will-larsons-macbook.local'

And we can verify the node is accessible:

bash-3.2$ ./check_erlang_node.sh -e erl -n my_node@`hostname` -c cookie
OK - Node 'my_node@will-larsons-macbook.local' running.

Next we can check for started applications (note that kernel2 is a made up application which doesn't exist, while kernel is a real application which is indeed running):

bash-3.2$ ./check_erlang_application.sh -e erl -c cookie -n my_node@`hostname` -a kernel2
CRITICAL - Applications ["kernel2"] not running on Node 'my_node@will-larsons-macbook.local'.
bash-3.2$ ./check_erlang_application.sh -e erl -c cookie -n my_node@`hostname` -a kernel
OK - Applications ["kernel"] running on Node 'my_node@will-larsons-macbook.local'.

And that is all there is to it.