README for MuninLite ==================== MuninLite is a single Bourne Shell script that implements the Munin protocoll as well as some Linux specific plugins. The motivation for developing MuninLite was to provide a simple Munin Node, using inetd on systems without a full featured Perl and/or bash or a busybox system. MuninLite is Copyright (C) 2007 Rune Nordbøe Skillingstad and released under GPLv2 (see LICENSE file) Features -------- MuninLite implements the following plugins: * df * cpu * if_ * if_err_ * load * memory * processes * swap * netstat * uptime * interrupts * irqstats Included files -------------- * `Changelog`: Changelog * `CREDITS`: Credits to contributors * `LICENSE`: GPLv2 License * `Makefile`: Rules to make munin-node * `README`: This file * `TODO`: Things to do in future releases * `VERSION`: Current version * `munin-node.in`: The MuninLite script skeleton * `examples/xinetd.d/munin`: Sample xinetd configuration * `examples/inetd.conf`: Sample inetd.conf configuration * `examples/inetd.busybox`: Sample inetd.conf configuration for busybox * `examples/hosts.deny`: Sample hosts.deny configuration * `examples/hosts.allow`: Sample hosts.allow configuration * `plugins/cpu`: CPU usage plugin * `plugins/df`: Filesystem usage plugin * `plugins/if_`: Network interface traffic plugin * `plugins/if_err_`: Network interface errors plugin * `plugins/interrupts`: Interrupts & context switches plugin * `plugins/irqstats`: Individual interrupts plugin * `plugins/load`: Load average plugin * `plugins/memory`: Memory usage plugin * `plugins/netstat`: Netstat plugin * `plugins/processes`: Number of Processes plugin * `plugins/swap`: Swap in/out plugin * `plugins/uptime`: Uptime plugin Build requirements ------------------ * Make: not sure what requirements * Perl: even very old versions should work Requirements ------------ * Bourne Shell: ash or dash should be sufficient * grep: simple grep in busybox is sufficient * sed: simple sed in busybox is sufficient -- but a bit strange... * cut: cut in busybox is sufficient * wc: wc in busybox is sufficient * xargs: xargs in busybox is sufficient * inetd: inetd in busybox is sufficient Installation ------------ Download source and unpack it. Edit Makefile to suit your choice of plugins Make munin-node by running "make" ```shell $ make Making munin-node for muninlite version 0.9.14 Adding plugin df Adding plugin cpu Adding plugin if_ Adding plugin if_err_ Adding plugin load Adding plugin memory Adding plugin processes Adding plugin swap Adding plugin netstat Adding plugin uptime Adding plugin interrupts Adding plugin irqstats ``` Copy munin-node to a suitable location (/usr/local/bin/) and make it executable (there will be a "make install" at a later release) ```shell cp munin-node /usr/local/bin chmod +x /usr/local/bin/munin-node ``` Two typical ways of using MuninLite as a `munin-node` replacement are: * direct execution: suitable for remote hosts lacking root access (e.g. shared host) * TCP service via inetd/xinetd: providing a service that is accessible via TCP (like `munin-node`) Both approaches are detailed below. Installation for direct execution ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Configure the `address` setting of the node in the master's configuration with a suitable transport, e.g.: ``` [some.host.tld] address ssh://node-a.example.org/usr/local/bin/munin-node ``` The above example causes the master to connect to the node via ssh and to execute the MuninLite script directly. The running script responds to request from standard input just like it would do as a TCP service via inetd/xinetd. Installation as a TCP service (inetd/xinetd) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Add munin port to `/etc/services` (in case it is missing): ```shell echo "munin 4949/tcp lrrd # Munin" >>/etc/services ``` Configure inetd or xinetd to fork this script for request on the munin port (4949). Sample configuration for xinetd is located in `examples/xinetd.d/munin`: ```shell cp examples/xinetd.d/munin /etc/xinetd.d killall -HUP xinetd ``` Sample configuration for inetd is located in `examples/inetd.conf`: ```shell cat examples/inetd.conf >> /etc/inetd.conf killall -HUP inetd ``` Restrict access to munin port using hosts.allow and hosts.deny or add a rule to your favorite firewall config. Examples of hosts.allow/deny settings is provided in the examples directory. Iptables might be set with something like this: ```shell iptables -A INPUT -p tcp --dport munin --source 10.42.42.25 -j ACCEPT ``` Test ---- To test the script, just run it (`/usr/bin/local/munin-node`): ```shell $ /usr/local/bin/munin-node # munin node at localhost.localdomain help # Unknown command. Try list, nodes, config, fetch, version or quit list df cpu if_eth0 if_eth1 if_err_eth0 if_err_eth1 load memory version munins node on mose.medisin.ntnu.no version: 0.0.5 (munin-lite) quit ``` For inetd-test, try to telnet to munin port from allowed host. ```shell # telnet localhost 4949 Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. # munin node at localhost.localdomain help # Unknown command. Try list, nodes, config, fetch, version or quit list df cpu if_eth0 if_eth1 if_err_eth0 if_err_eth1 load memory version munins node on mose.medisin.ntnu.no version: 0.0.5 (munin-lite) quit Connection closed by foreign host. ``` Plugin configuration -------------------- To configure which plugins should be enabled, locate the `PLUGINS` variable in munin-node and remove unwanted plugins. There is no specific configuration for plugins. Munin configuration ------------------- Configure your /etc/munin/munin.conf as you would for a regular `munin-node`, if you configured MuninLite as a TCP service (e.g. via inetd/xinetd): ``` [some.host.tld] address 10.42.42.25 use_node_name yes ``` In case of direct execution of MuninLite on the remote host (without a TCP service), you need to configure a transport and execute the script directly: ``` [some.host.tld] address ssh://10.42.42.25/usr/local/bin/munin-node use_node_name yes ```