• Takes a daily snapshot of the primary disk without any user input

• Deletes all snapshots that are older than 7 days (default)

• [OPTIONAL] Snapshots can be kept for > 7 days

    Usage: ./snapshot.sh [-d <days>]
  
    Options:
  
       -d  Number of days to keep snapshots. Snapshots older than this number deleted.
           Default if not set: 7 [OPTIONAL]
  

• cURL must be installed

• The VM must have the sufficient gcloud permissions, including "compute" set to "enabled":

  http://stackoverflow.com/questions/31905966/gcloud-compute-list-networks-error-some-requests-did-not-succeed-insufficie#31928399

• Only works for the primary disk on VM
• Only manages snapshots created by the script

• Load the script on to the VM (do not run it from a remote source)

• Create a /var/log/cron directory for all cron outputs

• Create /var/log/cron/snapshot.log

• Change group to "adm":

  # chgrp adm /var/log/cron/snapshot.log

• Change permissions on the "snapshot.log" file:

  # chmod 664 /var/log/cron/snapshot.log

• Run the script from a cronjob. Note this must be done as whatever user has access to gcloud compute (usually the Google user that created the VM):

    0 05 * * * /path/to/snapshot.sh >> /var/log/cron/snapshot.log 2>&1
  

• Add the /var/log/cron directory folder to logrotate: /etc/logrotate.d/cron

    /var/log/cron/*.log {
        daily
        missingok
        rotate 14
        compress
        notifempty
        create 664 root adm
        sharedscripts
    }
  

If you download the script and open it on a Windows machine, that may add windows character's to the file: jacksegal#1.