Log into the VM using gcloud compute ssh VM_NAME or web ssh.
Then edit /etc/ssh/sshd_config and change PasswordAuthentication no to PasswordAuthentication yes and restart sshd service: systemctl restart sshd
After that, you can add user and grant password adduser testuser
Then you can use username and password to log into the VM: ssh testuser@PUBLIB_IP_OF_VM
Hope it helps!!
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