At first, you should collect logs:
- Go to
Compute Engine -> VM instances -> click on NAME_OF_YOUR_VM -> at the VM instance details find section Logs and click on Serial port 1 (console)
- Reboot your VM instance again.
- Check full boot log for any errors or/and warnings.
If your VM instance doesn't start up verify that your disk has a valid file system and a valid master boot record (MBR) by following the documentation General troubleshooting.
If you found errors/warning related to disk space you can try to resize it accordingly to the documentation Resizing a zonal persistent disk, also accordingly to the article Recovering an inaccessible instance or a full boot disk:
If an instance is completely out of disk space or if it is not running
a Linux guest environment, then automatically resizing your root
filesystem isn't possible, even after you've increased the size of the
persistent disk that backs it. If you can't connect to your instance,
or your boot disk is full and you can't resize it, you must create a
new instance and recreate the boot disk from a snapshot to resize it.
Otherwise try to troubleshoot your VM instance via serial console:
Enable serial console connection with gcloud command:
gcloud compute instances add-metadata NAME_OF_YOUR_VM_INSTANCE \
--metadata serial-port-enable=TRUE
or go to Compute Engine -> VM instances -> click on NAME_OF_YOUR_VM_INSTANCE -> click on EDIT -> go to section Remote access and check Enable connecting to serial ports
Create temporary user and password to login: shutdown your VM and set a startup script by adding at the section Custom metadata key startup-script and value:
#!/bin/bash
useradd --groups google_sudoers tempuser
echo "tempuser:password" | chpasswd
and then start your VM.
Connect to your VM via serial port with gcloud command:
gcloud compute connect-to-serial-port NAME_OF_YOUR_VM_INSTANCE
or go to Compute Engine -> VM instances -> click on NAME_OF_YOUR_VM_INSTANCE -> and click on Connect to serial console
Check what went wrong.
Disable access via serial port with gcloud command:
gcloud compute instances add-metadata NAME_OF_YOUR_VM_INSTANCE \
--metadata serial-port-enable=FALSE
or go to Compute Engine -> VM instances -> click on NAME_OF_YOUR_VM_INSTANCE -> click on EDIT -> go to section Remote access and uncheck Enable connecting to serial ports. Keep in mind that accordingly to the documentation Interacting with the serial console:
Caution: The interactive serial console does not support IP-based access
restrictions such as IP whitelists. If you enable the interactive
serial console on an instance, clients can attempt to connect to that
instance from any IP address. Anybody can connect to that instance if
they know the correct SSH key, username, project ID, zone, and
instance name. Use firewall rules to control access to your network
and specific ports.
If you weren't able to connect via serial console, try follow the documentation Troubleshooting SSH section Inspect the VM instance without shutting it down and inspect the disk of your VM on another VM. Same way you can transfer your data to another working VM instance.
