AWS cross region replication lambda service

aws-cross-region-replicate-all-lambda.py

# aws-cross-region-replicate-all-lambda.py
# @author: Nestor Urquiza
# @date: 20161226
# @description: Cross Region replication script. Use at your own risk!
# Customize this lambda looking for TOCHANGETHIS: identifier

import boto3
import botocore
from pprint import pprint

# TOCHANGETHIS:
# Environment specific constants
SOURCE_REGION = 'us-east-1'
TARGET_REGION = 'us-west-1'

# Define clients for the two regions
source_ec2 = boto3.client('ec2', region_name=SOURCE_REGION)
target_ec2 = boto3.client('ec2', region_name=TARGET_REGION)

# Define the array to keep track of valid descriptions to be replicated
snapshot_descriptions = []

def lambda_handler(event, context):
    # TOCHANGETHIS:
    # Define what specific instance tags should be scanned for replication
    # In this case test and production instances are tagged for in region backups (BCP)
    # We use those same in region backup tags to drive the cross region replication (DR)
    reservations_test = source_ec2.describe_instances(
        Filters=[
            {'Name': 'tag:scheduler:ebs-snapshot:test', 'Values': ['true']},
        ]
    ).get(
        'Reservations', []
    )
    reservations_prod = source_ec2.describe_instances(
        Filters=[
            {'Name': 'tag:scheduler:ebs-snapshot:prod', 'Values': ['true']},
        ]
    ).get(
        'Reservations', []
    )
    reservations = reservations_test + reservations_prod
    instances = sum(
        [
            [i for i in r['Instances']]
            for r in reservations
        ], [])

    # A list of replicated snapshots will be printed
    print "Replicated:"
    print "InstanceName\tInstanceId\tVolumeName\tVolumeId\tSnapshotId\tSnapshotState"
    for instance in instances:
        instance_id = instance['InstanceId']
        try:
            instance_name = [
            str(t.get('Value')) for t in instance['Tags']
            if t['Key'] == 'Name'][0]
        except IndexError:
            instance_name = 'None'

        # Find volumes in used by qualified for replication instances
        for dev in instance['BlockDeviceMappings']:
            if dev.get('Ebs', None) is None:
                continue
            volume_id = dev['Ebs']['VolumeId']
            # Get the volume name
            volume = source_ec2.describe_volumes(
                Filters = [
                    {
                        'Name': 'volume-id',
                        'Values': [
                            volume_id,
                        ]
                    }
                ]
            )['Volumes'][0]
            try:
                volume_name = [
                str(t.get('Value')) for t in volume['Tags']
                if t['Key'] == 'Name'][0]
            except IndexError:
                volume_name = 'None'

            # Find the snapshots for the volume
            source_snapshots = source_ec2.describe_snapshots(
                Filters = [
                    {
                        'Name': 'volume-id',
                        'Values': [
                            volume_id,
                        ]
                    }
                ]
            )['Snapshots']

            for snapshot in source_snapshots:
                snapshot_id = snapshot['SnapshotId']
                snapshot_state = snapshot['State']

                # Snapshots that are not completed do not qualify for replication
                if(snapshot_state != 'completed'):
                    continue
                snapshot_description = instance_name + ':' + volume_name + ':' + snapshot_id

                # Keep track of those snapshots description we do want in the target
                snapshot_descriptions.append(snapshot_description)

                # Find any target snapshot that is already a replica
                target_snapshots = target_ec2.describe_snapshots(
                    Filters = [
                        {
                            'Name': 'description',
                            'Values': [
                                snapshot_description,
                            ]
                        }
                    ]
                )['Snapshots']

                # Replicate only those snapshots that were not replicated before
                if not target_snapshots:
                    try:
                        target_snapshot = target_ec2.copy_snapshot(
                            SourceRegion=SOURCE_REGION,
                            SourceSnapshotId=snapshot_id,
                            Description=snapshot_description,
                            DestinationRegion=TARGET_REGION
                        )
                    except botocore.exceptions.ClientError:
                        # Swallow the exception. Most likely more than 5 snapshots are being replicated
                        target_snapshot = None

                    if(target_snapshot):
                        print '%s\t%s\t%s\t%s\t%s\t%s' % (
                            instance_name, instance_id, volume_name, volume_id, snapshot_id, snapshot_state)

    # TOCHANGETHIS: Feel free to activate all the following code but be aware of possible accidental deletion of target snapshots
    # Delete the target snapshots that are not in the source
    '''
    OWNER_ID = '000000000000'
    target_snapshots = target_ec2.describe_snapshots(
        Filters = [
            {
                'Name': 'owner-id',
                'Values': [
                    OWNER_ID,
                ]
            }
        ]
    )['Snapshots']
    for snapshot in target_snapshots:
        if snapshot['Description'] not in snapshot_descriptions and snapshot['State'] == 'completed':
            snapshot_id = snapshot['SnapshotId']
            target_ec2.delete_snapshot(
                SnapshotId = snapshot_id
            )
            print "Snapshot %s deleted from %s" % (
                snapshot_id, TARGET_REGION)
    '''