munin on ssh jump

munin 是一个优秀的监控工具。不过网上对于如何通过跳板机连接目标机的资料不多，本篇文章是一个当时的试验记录，先放在这里，方便后面如果再次查阅的话.

Ensure you can access workers/nodes with your pubkey on munin master side.
On nodes, ensure installing munin-node(that’s all done on all debci workers)
On munin master, to install munin and then: a. sudo -u munin -s bash # enter into munin namespace. -s can avoid permission issue, but forget which link cd # return munin’s default home : /var/lib/munin/ b. copy private key to /var/lib/munin/.ssh/ In my case is /var/lib/munin/.ssh/vimer_id_ed25519. The key is the one we mentioned above. chown munin to all files. b. Configure .ssh/config

Host debian-10
    HostName 127.0.0.1
    Port 22
    User vimer
    ProxyCommand ssh jump-host -W %h:%p
    IdentityFile /var/lib/munin/.ssh/vimer_id_ed25519

Host jump-host
    HostName lab.com
    Port 22
    ServerAliveInterval 120
    User vimer
    IdentityFile /var/lib/munin/.ssh/vimer_id_ed25519

This is identical to your ~/.ssh/config except ` IdentityFilearg forcely. Image under munin namespace, you have to log in on jump host and workers withuser name`.

On another terminal, we need to configure /etc/munin/munin.conf which is conf file of munin. Adding something like below:

[debian-01]
        address ssh://vimer.7766.org:12345 -W localhost:4949
        use_node_name yes

[debian-10]
        address ssh://vimer@debci-10:12345 -W localhost:4949
        use_node_name yes

then sudo systemctl restart munin.

Backing to the previous terminal, you can test it by manual:

munin@debian:~$ /usr/share/munin/munin-update --debug --nofork --host
debian-06 --service df

the --host is what you want to debug. If everything is okay, you will see log:

munin@debian:~$ /usr/share/munin/munin-update --debug --nofork --host
debian-06 --service df
2024/04/19 02:42:51 [DEBUG] Creating new lock file
/var/run/munin/munin-update.lock
2024/04/19 02:42:51 [DEBUG] Creating lock :
/var/run/munin/munin-update.lock succeeded
2024/04/19 02:42:51 [INFO]: Starting munin-update
2024/04/19 02:42:52 [DEBUG] Creating new lock file
/var/run/munin/munin-debian-06.lock
2024/04/19 02:42:52 [DEBUG] Creating lock :
/var/run/munin/munin-debian-06.lock
succeeded
2024/04/19 02:42:52 [DEBUG] Reading state for
debian-06 in
/var/lib/munin/state-debian--06.storable
2024/04/19 02:42:52 [INFO] starting work in 1387300 for
debian-06 (ssh://vimer@debian-06:13321 -W localhost:4949).
2024/04/19 02:42:52 [DEBUG] open3(ssh -o
ChallengeResponseAuthentication=no -o StrictHostKeyChecking=no -p
13321 vimer@debian-06  -W localhost:4949)
2024/04/19 02:42:53 [INFO] node debian-06 advertised itself
as debci-bj-06 instead.
2024/04/19 02:42:53 TLS set to "disabled".
2024/04/19 02:42:53 [DEBUG] Negotiating capabilities

If you have error generated, you can execute ssh -o ChallengeResponseAuthentication=no -o StrictHostKeyChecking=no -p 13321 vimer@debian-06 -W localhost:4949 -vvv by hand to see what happened on both side.

All steps are done as my testing. Two usefully log: /var/log/munin/munin-update.log for munin master and the other is /var/log/munin/munin-node.log for munin node. ```

munin on ssh jump

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