Make snapshot backups of AWS instances. Created to have a simple binary distribution inspired by http://bit.ly/PDDaxI

• there is no more than one EBS root and one additional EBS volume.
• The Name 'tag' has some value in it.
• instances to be bakced up have an env tag with the value "prod"

NB: these settings are untested and I migh thave spelled the specifics incorrectly.

example crontab entry to keep 7 daily snapshots
0   3  *   *   *   /usr/local/bin/snapshot -count 7
example crontab entry to keep 3 weekly snapshots
0   5  */7  *  *   /usr/local/bin/snapshot -period weekly

NB: You will need to run the script with credentials that have something like the following permissions -- either IAM creds or on an instance launched into appropriate IAM role with permissions like the following:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "AllowEc2BackupSnapshotManagement",
      "Effect": "Allow",
      "Action": [
        "ec2:CopySnapshot",
        "ec2:CreateSnapshot",
        "ec2:CreateTags",
        "ec2:DeleteSnapshot",
        "ec2:DescribeInstances",
        "ec2:DescribeReservedInstances",
        "ec2:DescribeSnapshotAttribute",
        "ec2:DescribeSnapshots",
        "ec2:DescribeTags",
        "ec2:DescribeVolumes",
        "ec2:ModifySnapshotAttribute"
      ],
      "Resource": [
        "*"
      ]
    }
  ]
}

1. Relies on cron for time deltas. Doesn't look at last backup time, just makes a new snapshot. This means running it repeatedly will delete older snapshots leaving you with all very recent snapshots. Ideally shouldn't create a new snapshot if hte last was less than period. This requires period be more than a string.

2. Doesn't alert when there are problems. Ideally should send notifications to an SNS topic.... like http://bit.ly/PDDe0r