Glusterfs Munin plugins

README.mkd

About

This is the first draft of a munin 1 plugin for glusterfs. 2 It's a bit of a hack, because the only way to get stats out of glusterfs is to add a debug translator, set an extended attribute, and scan the server's logfile for output. Some kind of executable utility interface to these data would be really nice to have.

Pre-requisites

Because of the way the io-stats debug translator* 3 works, one must mount the filesystem on the server as a client. The underlying filesystem must be mounted with the user_xattr option, and the setfattr utility must be available in your standard path. Finally, you must add the io-stats debug translator to your server's configuration. Ex:

    volume io-stats
            type debug/io-stats
            option dump-fd-stats true
            subvolumes brick
    end-volume

Configuration

Place the glusterfsd file in /etc/munin/plugins, and edit the variables at the beginning of the file. Be sure that CLIENTFS is set to the path of the gluster filesystem where mounted as a client, and that LOGFILE is set to the full path of the server logfile. (The default should be correct for the debian packaged version of glusterfs) Then, restart munin-node, and the graph should be configured automatically.

Troubleshooting

The standard directions on the munin wiki 4 will probably be of help. If stats are not getting output with a 'list' command, try manually running the setfattr command:

setfattr -n trusted.io-stats-dump /path/to/glusterfs

If that gives an error, you need to enable extended attributes for the underlying filesystem, or install the attr utilities. (or maybe both) If that does not give an error, check the server log file for output. If there is none, check that your translators are configured properly. (Be sure that they "chain" properly)

Footnotes

  • Unfortunately, the io-stats translator is not documented on the wiki 5 at this time.