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Get munin node slave to report to a munin master

Escape the rate race, retire by 30.

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Munin is old school but it works so I keep installing it. Or maybe I’m old and I think of Prometheus the same way old people think of rap music 🙊 Regardless let’s install munin in a master / slave configuration.

Some assumptions:

Slave

sudo apt install munin-node

Open up the firewall so the master can get in

sudo ufw allow from 99.123.123.123 to any port 4949
sudo ufw allow from 99.123.123.123 to any port 4948

Setup your plugins. Let me show you with nginx

sudo apt install libwww-perl
sudo ln -s /usr/share/munin/plugins/nginx_request /etc/munin/plugins/nginx_request
sudo ln -s /usr/share/munin/plugins/nginx_status /etc/munin/plugins/nginx_status

In order to get this to work nginx iteslf must be configured to respond on localhost to nginx_request and nginx_status via a block like so in /etc/nginx/sites-enabled/monit

server {
  listen   80;
  ...
    location /nginx_status {
    stub_status on;
    access_log   off;
    allow 127.0.0.1;
    deny all;
  }
}

Here is another popular plugin config: PostgreSQL

sudo ln -s /usr/share/munin/plugins/postgres_bgwriter /etc/munin/plugins/postgres_bgwriter
sudo ln -s /usr/share/munin/plugins/postgres_cache_ /etc/munin/plugins/postgres_cache_ALL
sudo ln -s /usr/share/munin/plugins/postgres_checkpoints /etc/munin/plugins/postgres_connections_ALL
sudo ln -s /usr/share/munin/plugins/postgres_connections_db /etc/munin/plugins/postgres_connections_db
sudo ln -s /usr/share/munin/plugins/postgres_locks_ /etc/munin/plugins/postgres_locks_ALL
sudo ln -s /usr/share/munin/plugins/postgres_querylength_ /etc/munin/plugins/postgres_querylength_ALL
sudo ln -s /usr/share/munin/plugins/postgres_size_ /etc/munin/plugins/postgres_size_ALL
sudo ln -s /usr/share/munin/plugins/postgres_transactions_ /etc/munin/plugins/postgres_transactions_ALL
sudo ln -s /usr/share/munin/plugins/postgres_users /etc/munin/plugins/postgres_users
sudo ln -s /usr/share/munin/plugins/postgres_xlog /etc/munin/plugins/postgres_xlog

Restart munin-node

sudo systemctl restart munin-node

Master

Install munin

sudo apt install munin

Notify munin master of the new node

[slave;slave.com]
  address 88.123.123.123
  use_node_name yes

Restart munin

sudo systemctl restart munin

Check that the link to the slave is working:

telnet 88.123.123.123 4949

You can even verify that munin is responding back through telnet i.e.

fetch df

should give you back disk information. And then you wait because waiting for munin to do it’s thing is like waiting at the DMV.

You probably want to force an update cause time is money

su - munin --shell=/bin/bash -c "/usr/share/munin/munin-update -debug"