Munin : Set Thresholds2026/06/10

	The monitoring target items are set as plugins and thresholds are defined in some plugins by default, but if you'd like to add more thresholds to a plugin, configure like follows.
[1]	It's possible to see plugins like follows.

# current enabled plugins are located under the directory below

root@dlp:~#

ls /etc/munin/plugins

cpu        entropy        if_enp1s0      load         open_inodes  threads
df         forks          if_err_enp1s0  memory       proc_pri     uptime
df_inode   fw_packets     interrupts     munin_stats  processes    users
diskstats  http_loadtime  irqstats       open_files   swap         vmstat

# installed plugins are located under the directory below

root@dlp:~#

ls /usr/share/munin/plugins

acpi                      perdition
amavis                    pgbouncer_connections
apache_accesses           pgbouncer_requests
apache_processes          ping_
apache_volume             plugin.sh
apc_envunit_              plugins.history
apc_nis                   pm3users_
apt                       pop_stats
apt_all                   port_
bind9                     postfix_mailqueue
.....
.....

[2]	It's possible to display current values for each plugin.

# display values for cpu plugin

root@dlp:~#

munin-run cpu

user.value 2160
nice.value 589
system.value 1402
idle.value 187512
iowait.value 1584
irq.value 0
softirq.value 8
steal.value 0
guest.value 0

# display values for df plugin

root@dlp:~#

munin-run df

_dev_mapper_ubuntu__vg_ubuntu__lv.value 26.3091888233636
_dev_shm.value 0
_run.value 0.150603275333828
_tmp.value 0.000229929457642395
_dev_vda2.value 5.35645579144472

[3]	Set threshold's value in munin.conf like follows. ⇒ [plugin name].[field name].[warning \| critical] min-value:max-value The field name is just the one which is displayed when executing "munin-run" command. The min-value or max-value can be omitted.

root@dlp:~#

vi /etc/munin/munin.conf

# set threshold on target node
[dlp.srv.world]
    address 127.0.0.1
    use_node_name yes
    # set 80% of warning and 90% of critical for user field in cpu plugin
    cpu.user.warning :80
    cpu.user.critical :90
    # set 80% of warning and 90% of critical for /tmp partition field in df plugin
    df._tmp.warning :80
    df._tmp.critical :90

[4]	If you configured notification setting and a value is over from the threshold's value, the email is sent like follows.

Return-Path: <munin@dlp.srv.world>
X-Original-To: root
Delivered-To: root@dlp.srv.world
Received: by dlp.srv.world (Postfix, from userid 105)
        id E08C4603D0; Wed, 10 Jun 2026 00:35:04 +0000 (UTC)
Subject: Munin-notification for srv.world::dlp.srv.world
To: root@dlp.srv.world
User-Agent: mail (GNU Mailutils 3.20)
Date: Wed, 10 Jun 2026 00:35:04 +0000
Message-Id: <20260610003504.E08C4603D0@dlp.srv.world>
From: munin application user <munin@dlp.srv.world>

srv.world :: dlp.srv.world :: Disk usage in percent
        CRITICALs: /tmp is 91.81 (outside range [:90]).
        OKs: /dev/shm is 0.00, /boot is 5.36, /run is 0.15, / is 26.31.

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