[munin-users] migrating munin plugins from Linux to FreeBSD isn't easy - munin plugins needed for FreeBSD 6.2

[Pierre B. <pi...@ba...>]

Hi there,

I'm using munin at work and at home on various Linux distributions and I
find it's a very nice program.

I've just installed FreeBSD 6.2 on some machine and configured it as a
munin-node.
To install the munin-node scripts I (obviously) did:
cd /usr/ports/sysutils/munin-node/
make install

And then I've got the following munin plugins installed on my FreeBSD 6.2system:
[root@fire] /usr/local/share/munin/plugins>ls
acpi                            netstat
amavis
apache_accesses                 ntp_
apache_processes                ntp_states
apache_volume                   nut_misc
apc_envunit_                    nut_volts
apc_nis                         open_files
bind9                           perdition
bind9_rndc                      ping_
courier_                        plugins.history
courier_mta_mailqueue           pm3users_
courier_mta_mailstats           pop_stats
courier_mta_mailvolume          postfix_mailqueue
cpu                             postfix_mailstats
cupsys_pages                    postfix_mailvolume
df                              processes
df_inode                        ps_
dhcpd3                          psu_
exim_mailqueue                  samba
exim_mailqueue_alt              sendmail_mailqueue
exim_mailstats                  sendmail_mailstats
foldingathome                   sendmail_mailtraffic
foldingathome_rank              smart_
foldingathome_wu                snmp__df
hddtemp                         snmp__fc_if_
hddtemp2                        snmp__fc_if_err_
hddtemp_smartctl                snmp__if_
hddtempd                        snmp__if_err_
if_                             snmp__load
if_errcoll_                     snmp__processes
snmp__sensors_fsc_bx_fan
ipac-ng                         snmp__sensors_fsc_bx_temp
ircu                            snmp__sensors_fsc_fan
load                            snmp__sensors_fsc_temp
loggrep                         snmp__sensors_mbm_fan
mailman                         snmp__sensors_mbm_temp
mailscanner                     snmp__sensors_mbm_volt
mbmon_                          snmp__users
memory                          spamstats
mhttping                        squid_cache
multips                         squid_icp
munin_graph                     squid_requests
munin_update                    squid_traffic
mysql_bytes                     surfboard
mysql_isam_space_               swap
mysql_queries                   sybase_space
mysql_slowqueries
mysql_threads                   vmstat
named


I have then gotten the following munin plugins from Debian 3.1 (sarge)
install:
iostat
nfs_client
users
uptime

Of course Perl scripts run on both Linux and FreeBSD. But, some Linux
scripts do not work on FreeBSD, mainly because they rely on the /proc
filesystem, which is present in Linux but not in FreeBSD. Well, actually you
*can* mount a proc filesystem in FreeBSD by adding the following line to
your /etc/fstab:
linprocfs               /compat/linux/proc   linprocfs   rw     0       0
And then creating a symbolic link:
ln -s /usr/compat/linux/proc /proc

... but:
1) Not everybody wants to mount the linprocfs filesystem in FreeBSD.
2) The FreeBSD linproc filesystem isn't mounted as /proc but as
/compat/linux/proc
3) The FreeBSD linproc filesystem doesn't have all the features the Linux
/proc filesystem has.

So we've got these four plugins: iostat, nfs_client, users, uptime, let's
see how we can migrate them from Linux to FreeBSD:

The easiest is users. You don't have to change a single thing when
installing in in FreeBSD. It does not use the /proc filesystem at all. It
uses the who command:
open (WHO,"who|tr -s ' '|cut -d' ' -f2|cut -d'/' -f1|");

Second in difficulty is the uptime script. It relies on the /proc
filesystem. But if you mount the linproc filesystem in FreeBSD and do ln -s
/usr/compat/linux/proc /proc, the script will work in FreeBSD.
You may ask: "Well, why don't you rewrite the script so that it calls the
uptime command instead of relying on the /proc filesystem ?"  That would
work, *but* then the script will report the uptime as an integer (number of
days) and not as a real number like the current uptime script does. So the
graph would be completely different.

Third and fourth in difficulty are iostat and nfs_client.
They both try to access directories that do not exist in the linproc
filesystem.
Error messages from iostat:
[root@fire] /usr/local/share/munin/plugins>./iostat
grep: /proc/partitions: No such file or directory

Error messages from nfs_client:
[root@fire] /usr/local/share/munin/plugins>./nfs_client
getattr.value grep: /proc/net/rpc/nfs: No such file or directory
setattr.value grep: /proc/net/rpc/nfs: No such file or directory
(18 more lines, not included)

It would be nice if someone had already migrated these scripts to FreeBSD :)


Thank you,
-- 
Pierre Bauduin
Linux enthusiast since 1996
Debian GNU/Linux user
Red Hat Certified Engineer
website: http://pierre.baudu.in/
mail/msn/gaim: pi...@ba...