add netdata monitoring

site/content/services/shell.md

@@ -22,7 +22,7 @@ auth:               ssh-ed25519 xxxxxxxxx
 ```
 
 Log in using the key specified in the auth method:
-```
+```shell
 ssh foo@shell.fr-rbx1.burble.dn42
 ```
 
@@ -63,6 +63,12 @@ The registry import process currently limits the initial shell to /bin/bash
 and currently this cannot be changed. If you want to use something different,
 just exec to the new shell in your .profile or .bashrc.
 
+Example .bashrc line for zsh:
+
+```shell
+if [[ $- == *i* ]]; then exec /usr/bin/zsh; fi
+```
+
 ### Clearnet
 
 Clearnet access is provided. Rate limiting allows for a small amount of
@@ -74,6 +80,10 @@ you should be better off using your own clearnet access for large downloads.
 The shell servers are monitored using netdata and prometheus, with performance
 graphs available in [grafana](https://grafana.burble.dn42).
 
+The netdata dashboard is also directly accessible:
+
+- [http://shell.fr-rbx1.burble.dn42:19999](http://shell.fr-rbx1.burble.dn42:19999)
+
 ## Acceptable Use
 
 The objective of the burble.dn42 shell service is to provide a free, open,