README

Create automatic AWS EC2 snapshots with limits on the total number of snapshots created and the interval which the snapshots are created.

For example, you could create a snapshot every day and only keep the last 7 for a running week's worth of snapshots. Or create a snapshot once a week and only keep the last 4 so you would have a running month's worth of snapshots.

Requirements

• AWS CLI
• AWS IAM snapshot permissions (example policy)
• PHP 5.5+
• Access to crontab (or some other job scheduler)

AWS CLI installation

sudo apt-get install python-pip php5-cli
sudo pip install awscli

// set credentials (Access Key ID, Secret Access Key) and region - ie: us-east-1, us-west-1
aws configure

Setup

This assumes you've already installed and configured AWS CLI and added the correct IAM permissions within your AWS console.

1. Create a PHP script to use the library

Use composer to autoload all the necessary classes.

Setup AWS CLI installation directory (using the value from which aws) and configure your volumes.

Finally wire the services and test run your cli task. You can also change a description prefix that is used by this library to pick snapshots from the server. This is done via the second argument of Snapshots::run()

<?php

$awsCliPath = '/usr/local/bin/aws';
$date = date('Y-m-d');
$volumes = [
   new \AwsSnapshots\Options\VolumeIntervalBackupOptions('vol-123af85a', 7, '1 day', 'dev-server-backup'),
   new \AwsSnapshots\Options\VolumeIntervalBackupOptions('vol-321bg96c', 4, '1 week', 'image-server-' . $date),
   new \AwsSnapshots\Options\VolumeBackupOptions('vol-987ab12a', 10, 'cache-backup-backup'),
];

$awsCliHandler = new \AwsSnapshots\Cli\AwsCliHandler($awsCliPath);

$snapshots = new \AwsSnapshots\Snapshots($awsCliHandler);
$snapshots->run($volumes);

Example wiring in Symfony services.yml:

    aws_snapshots.cli.aws_cli_handler:
        class: AwsSnapshots\Cli\AwsCliHandler
        arguments:
            - '%aws.cli_tool.path%'

    aws_snapshots.snapshots:
        class: AwsSnapshots\Snapshots
        arguments:
            - '@aws_snapshots.cli.aws_cli_handler'

Volume Configuration

There are two types of volume configurations.

Both of them maintain a certain number of snapshots (snapshot count limit) of a volume with specified description. The description is used by this library to select snapshots. When you create a manual snapshot of a same volume, it will be ignored.

Interval Backups

You can schedule only one backup within a specified interval by using:

new VolumeIntervalBackupOptions(volumeId, snapshotCountLimit, interval, description)

where the arguments are:

Regular Backups

You can also backup a volume every time you run the PHP task by using:

new VolumeBackupOptions(volumeId, snapshotCountLimit, description)

where the arguments are:

Interval Values

The interval format is number type (e.g. 30 minute):

• a number is integer
• a type is one of following units:
  • hour
  • day
  • week
  • month
  • year

2. Add a cron job

The cron job schedule will depend on your configuration. You should run the cron command in a period that is as long as the smallest interval of your volume backups.

In the example you have to run the CRON task at least once a day. It will create snapshot of:

• dev-server-backup every day at 3:00 am,
• image-server-${date} every week on a day you started it for the first time at 3:00 am
• cache-server every time you run the task (if you run it 3× a day it will create 3 snapshots)

# run the cron job every night at 3:00 am
00	03	* * * /usr/bin/php /root/scripts/run-snapshots.php

Example IAM Policy

This is a minimal policy that includes ONLY the permissions needed to work. You could also limit the "Resources" option to restrict it even further.

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "ec2:CreateSnapshot",
        "ec2:DeleteSnapshot",
        "ec2:DescribeSnapshots"
      ],
      "Resource": [
        "*"
      ]
    }
  ]
}

Questions, issues or suggestions

Please use the issues section for any questions or issues you have. Also, suggestions, pull request or any help is most welcome!