Add instance logs and disk space to troubleshooting page

docs/troubleshooting/providers/google.md

@@ -3,6 +3,22 @@
 This is an incomplete list of issues people have run into when running
 TLJH on Google Cloud, and how they have fixed them!
 
+## Viewing VM instance logs
+
+In addition to [installer, JupyterHub, traefik, and other logs](#troubleshooting-logs) 
+you can view VM instance logs on Google Cloud to help diagnose issues. These logs will contain
+detailed information and error stack traces and can be viewed from
+[Google Cloud Console -> Compute Engine -> VM instances](https://console.cloud.google.com/compute/instances). 
+Once you select your TLJH instance, select **Serial port 1 (console)**:
+```{image} ../../images/providers/google/serial-port-console.png
+:alt: Serial port 1 (console) under Logs heading
+```
+
+:::{tip}
+The console will show the logs of any startup scripts you configured for your instance,
+making it easy to see if it has completed and/or encountered any errors.
+:::
+
 ## 'Connection Refused' error after restarting server
 
 If you restarted your server from the Google Cloud console & then try to access
@@ -15,3 +31,16 @@ IP address, you might have to change it to point to the new correct IP.
 
 You can prevent External IP changes by [reserving the static IP](https://cloud.google.com/compute/docs/ip-addresses/reserve-static-external-ip-address#promote_ephemeral_ip)
 your server is using.
+
+## Issues caused by lack of disk space
+
+If your boot disk becomes full, this can cause your instance to become unavailable,
+among other problems. If your instance appears up and running in the console but
+you cannot access it at your configured external IP/domain name, this could be caused
+by a lack of disk space. 
+
+You can explore your [VM logs in the console](#viewing-vm-instance-logs) to determine 
+if any issues you are experiencing indicate disk space issues. 
+
+To resolve these types of issues, you can 
+[increase your boot disk size](#howto-providers-google-resize-disk).