This script creates snapshots from EBS volumes and copies them across regions for disaster recovery. If your volume is used for database storage, this script can make sure your backup is consistent by flushing and stopping writes until the snapshot is complete.
This script also purges old snapshots according to a simple retention policy specified by you, to keep your Amazon AWS bills under control.
Just use the gem command to install:
$ gem install snapscatter
You can have a look at the commands and options by just typing the name of the executable:
Snapscatter commands:
snapscatter create # Create snapshots, optionally copying them to an alternate region
snapscatter help [COMMAND] # Describe available commands or one specific command
snapscatter list # Show available snapshots
snapscatter purge # purge snapshots older than the specified number of days
snapscatter targets # Show volumes tagged for backup
snapscatter version # Shows current version of the program
The best way to use this script is to make a shell wrapper for it that exports your AWS credentials as environment variables and then put it under the control of the cron demon.
You should use the AWS console to mark the volumes you want to be backed up using the tag Backup with a
value of true. You can then check the list of these volumes using the command targets.
Use the command create to take snapshots of all the tagged volumes. Snapshots will be taken to your default
AWS region, but you can optionally supply the --alternate flag to create a copy onto another
region for disaster recovery.
Every snapshot taken will have the PurgeAllow tag set with the value of true. If for some reason you want
a snapshot not to be purged indefinitely, you can set this tag to any other value, or even remove the tag
altogether.
You can call the purge command to delete any snapshots older than 30 days. This is the default retention policy
but you can change it by using the optional -d flag (for --days).
Snapshots will be deleted from your default AWS region. If you supply the --alternate flag, snapshots will also
be purged from the alternate region.
You can also run this command with the -n (for --noaction) to only list the snapshots that would be purged
under the specified retention policy, no snapshot will be purged.
The list command will show all the snapshots subject to be purged, that is, all snapshots with the PurgAllow
tag set to true. The -f option for this command gives more information on every snapshot: snapshot id, volume id
and date of creation. Using the -r or --region flag you can change the target region.
If the volumes your attempting to snapshot are being used by a database, then you want to force a flush to disk and stop writing so you can have a consistent backup. This script can do that for you (currently it only supports MongoDB).
To use this feature, you can tag the volume with the Consistent tag. The value of this tag contains the connection
information, as key-value pairs separated by commas, so that the script can have access to the database, flush and
stop writes until the snapshot has been taken. Here's an example:
strategy: mongo, host: 127.0.0.1, port: 27017, usr: admin, pwd: 12345
Create a shell file like the following and put it under cron's control:
#!/bin/sh
export AWS_ACCESS_KEY_ID="YOURACCESSKEY"
export AWS_SECRET_ACCESS_KEY="YOURSECRETACCESSKEY"
snapscatter purge -d 20
snapscatter create --alternate="us-west-1"
You have to make two calls because the script won't purge and create snapshots on a single call.
- Take consistency specification out of the volume and put it in a configuration file
- More database connectors
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Add some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request