munin: all plugins fail with "can't drop privileges: setrgid() not implemented at /opt/local/lib/perl5/site_perl/5.12.4/Munin/Node/OS.pm line 261"

[pierre.bauduin@…]

On a brand new iMac running MacOSX 10.9 "Mavericks", I clean installed the munin port.

This port is the equivalent of the munin-node package on Debian. Basically it listens on port 4949 from the munin server. Commands from the munin server can be "list" to list all available plugins or "fetch <plugin>" to fetch a particular plugin. One can easily test the plugins by doing telnet 127.0.0.1 4949 then fetch <plugin>

Problem

All munin plugins fail with "#Bad exit":

telnet 127.0.0.1 4949
Trying 127.0.0.1...
Connected to localhost.
Escape character is
# munin node at albert
list
df df_inode http_loadtime if_en0 if_err_en0 load lpstat netstat ntp_offset processes users
fetch load
# Bad exit
.
fetch users
# Bad exit
.

Let's look what is going in the log file/opt/local/var/log/munin/munin-node.log:

2014/02/12-17:30:06 [27043] 	2014/02/12-17:30:06 [27061] Plugin 'users' Can't drop privileges: setruid() not implemented at /opt/local/lib/perl5/site_perl/5.12.4/Munin/Node/OS.pm line 261, <STDIN> line 19.\n. Bailing out.
2014/02/12-17:30:06 [27043] 	2014/02/12-17:30:06 [27063] Plugin 'if_err_en0' Can't drop privileges: setruid() not implemented at /opt/local/lib/perl5/site_perl/5.12.4/Munin/Node/OS.pm line 261, <STDIN> line 21.\n. Bailing out.
2014/02/12-17:30:06 [27043] 	2014/02/12-17:30:06 [27065] Plugin 'df' Can't drop privileges: setruid() not implemented at /opt/local/lib/perl5/site_perl/5.12.4/Munin/Node/OS.pm line 261, <STDIN> line 23.\n. Bailing out.
2014/02/12-17:30:06 [27043] 	2014/02/12-17:30:06 [27067] Plugin 'netstat' Can't drop privileges: setruid() not implemented at /opt/local/lib/perl5/site_perl/5.12.4/Munin/Node/OS.pm line 261, <STDIN> line 25.\n. Bailing out.
2014/02/12-17:30:06 [27043] 	2014/02/12-17:30:06 [27069] Plugin 'lpstat' Can't drop privileges: setruid() not implemented at /opt/local/lib/perl5/site_perl/5.12.4/Munin/Node/OS.pm line 261, <STDIN> line 27.\n. Bailing out.
2014/02/12-17:30:06 [27043] 	2014/02/12-17:30:06 [27071] Plugin 'load' Can't drop privileges: setruid() not implemented at /opt/local/lib/perl5/site_perl/5.12.4/Munin/Node/OS.pm line 261, <STDIN> line 29.\n. Bailing out.

Solution

The problem is actually in file /opt/local/etc/munin/munin-node.conf. Just change the user and group to:

user munin
group munin

Load and unload the munin-node plist:

sudo launchctl unload /Library/LaunchDaemons/org.macports.munin-node.plist 
sudo launchctl load /Library/LaunchDaemons/org.macports.munin-node.plist 

... and the munin plugins now run perfectly.

telnet 127.0.0.1 4949
Trying 127.0.0.1...
Connected to localhost.
Escape character is 
# munin node at albert
fetch cpu
system.value 0
user.value 1
idle.value 99
.
fetch users
tty.value 7
pty.value 0
pts.value 0
X.value 0
other.value 1
.

[raimue (Rainer Müller)]

Duplicate of #32141.