2) Now, let’s configure the Munin Node. The main configuration file is located at /etc/munin/munin-node.conf.

Options are:

• host_name: This is the hostname that Munin Master will use to identify the agent. If you have a custom agent hostname on the master, you should change it accordingly.
• ignore_file: Specifies which plugins should be ignored.
• paranoia: This option is either set to true or false. When set to true, Munin allows plugins to run only if they are owned by the root user.

Other common options include:

• log_level: A numerical value from 0 to 4, where 0 means no logging and 4 means very verbose logging.
• log_file: The location of the log file.
• pid_file: The location of the PID file.
• background: Set to 1 to run Munin in the background.
• user: Specifies the user from which Munin is executed.
• group: Specifies the group from which Munin is executed.
• setsid: When set to 1, the daemon will fork itself, freeing it from the command line and running as a daemon.
• global_timeout: Specifies the time interval to drop the connection to the master.
• timeout: Sets the timeout for each single plugin to hold the connection.
• allow: Defines what hosts may connect to this Munin node.
• cidr_allow: Specifies allowed hosts in CIDR notation (e.g., 192.0.2.1/32).
• cidr_deny: Similar to cidr_allow, but denies hosts.
• host: The IP address on which the Munin node listens.
• port: The port on which the Munin node listens.

Here’s an example of a typical Munin Node configuration file:

#
# Example config-file for munin-node
#

log_level 4
log_file /var/log/munin-node/munin-node.log
pid_file /var/run/munin/munin-node.pid

background 1
setsid 1

user root
group root

# This is the timeout for the whole transaction.
# Units are in sec. Default is 15 min
#
# global_timeout 900

# This is the timeout for each plugin.
# Units are in sec. Default is 1 min
#
# timeout 60

# Regexps for files to ignore
ignore_file [\#~]$
ignore_file DEADJOE$
ignore_file \.bak$
ignore_file %$
ignore_file \.dpkg-(tmp|new|old|dist)$
ignore_file \.rpm(save|new)$
ignore_file \.pod$

# Set this if the client doesn't report the correct hostname when
# telnetting to localhost, port 4949
#
host_name localhost.localdomain

# A list of addresses that are allowed to connect. This must be a
# regular expression, since Net::Server does not understand CIDR-style
# network notation unless the perl module Net::CIDR is installed. You
# may repeat the allow line as many times as you'd like

allow ^127\.0\.0\.1$
allow ^::1$

# If you have installed the Net::CIDR perl module, you can use one or more
# cidr_allow and cidr_deny address/mask patterns. A connecting client must
# match any cidr_allow, and not match any cidr_deny. Note that a netmask
# *must* be provided, even if it's /32
#
# Example:
#
# cidr_allow 127.0.0.1/32
# cidr_allow 192.0.2.0/24
# cidr_deny 192.0.2.42/32

# Which address to bind to;
host *
# host 127.0.0.1

# And which port
port 4949

3) Let’s add our master node to the allowed list. Open /etc/munin/munin-node.conf and edit the configuration accordingly.

allow ^127\.0\.0\.1$

To reflect the IP address of your Munin master node, update the “allow” or “cidr_allow” option in the /etc/munin/munin-node.conf file. In my case, with the IP address 185.181.8.78, the string should look like:

allow ^185\.181\.8\.78$

4) Now, initiate the Munin Node service, ensure it is set to start on boot, and verify its status to confirm smooth operation.

systemctl start munin-node
systemctl enable munin-node
systemctl status munin-node