Cannot Connect to VM from Console SSH

[Robert Bowron]

Have tried swapping with a new user and expanding the Boot Disk memory, but nothing gets me anywhere. Can connect to serial console, but do not recall setting a password on it.

[Digil (Google Cloud Platform Support)]

You can use the startup script to add a username and password for the serial port access. A few examples on how to add username and password for the serial console access are provided in these discussion threads(thread1 & thread2).

If the serial port access failed and 'Troubleshooting SSH' guide also didn't help you to access the VM, then the only option left would be to retrieve the data from your OLD VM through a new VM. You could either use the answer provided in the stackoverflow.com thread to achieve this or follow the steps mentioned below to copy the data from the affected(OLD) VMs disk.

1 Create a snapshot from the boot disk of the OLD VM 

2 Create a new VM. As a boot disk, you should use a Google public image (important- do not use the snapshot you created).

3 Once that instance is created, try to SSH into it just to test if you are able to access it. There should be no issue at this point with this VM instance, as this is a new instance using a fresh operating system.

4 In the newly created instance, click on the instance name (in the Console), and then click ‘Edit’ at the top of the page to edit the machine.

5 In the ‘Additional Disks’ section, click ‘Add item’.

6 In the ‘Name’ drop-down select ‘Create disk’. In the window that opens add a name for the disk, and in the ‘Source snapshot’ drop-down select the snapshot you created in Step 1. Now Click ‘Create’

7 Click ‘Save’ to save the instances new configuration.

8 Please SSH into the new instance, and run command $lsblk .

You will be able to see the new disk and partition added (It will most probably be named sdb1 but you should check this and take note).

9 Please run the following command which will create a mount point at /mnt/newdisk and then mounts the additional disk partition to that mount point. Note- substitute /dev/sdb1 in the below command with the name of the partition if it is different.

$ sudo mkdir /mnt/newdisk | sudo mount -o discard,defaults /dev/sdb1 /mnt/newdisk

The snapshots file system will now be mounted at /mnt/newdisk.

You should now be able to navigate the directories and retrieve any data. After retrieving the data, create a new VM with latest image and transfer the data to it. 

I hope this helps.

[Robert Bowron]

I ended up doing exactly this, just mount the old drive onto a new VM I had spun up. Thanks!