Lambda Function To Take Snapshot Of EBS Volume Based On EC2 Tags
Take Snapshot Of Secondary Volumes Of Instance Having particular Tag
Create AWS Lambda Function For EBS Snapshot Having Certain Tags On EC2 Instance
It is often required to take snapshot of EBS volume for backup as there could be important data residing on those volumes. This can be achieved by run some script on ec2 instance as a cron. But its very unreliable to run a script on some ec2 instance as the script may fail due to any reason and we won't come to know about it.
To solve this problem we will use a python script on AWS Lambda which can scheduled to run at required interval. You can also set cloudwatch alarm to trigger a mail if the lambda function return some error.
Note: We are going to take Snapshot of only secondary volumes as assuming for most of the databases, data resides on secondary disk instead of root volume.
Note: We are going to take Snapshot of only secondary volumes as assuming for most of the databases, data resides on secondary disk instead of root volume.
# End Goal
- Take Snapshot of only secondary volume
- Snapshot should be taken of a volume attached to an instance having a tag "Backup:true"
# Prerequisites
- IAM role (volume-snapshot-role) having policy to read read ec2 instance details and to create snapshot.
- Instance with secondary volume.
# IAM Role
IAM role should have following policy attached to it:
- AWS Managed Policy: AmazonEC2ReadOnlyAccess
- volume-snapshot-policy:
{ "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "logs:CreateLogGroup", "logs:CreateLogStream", "logs:PutLogEvents" ], "Resource": "arn:aws:logs:*:*:*" }, { "Effect": "Allow", "Action": [ "ec2:DescribeVolumeStatus", "ec2:DescribeVolumes", "ec2:DescribeSnapshots", "ec2:CreateSnapshot", "ec2:CreateTags" ], "Resource": "*" } ] }
# Lambda Function
Following is the lambda function snippet:from __future__ import print_function import boto3 from boto3 import resource ''' This script takes snapshot of volumes which are secondary volumes and are attached to instance having "Backup:true" tag ''' SNAPSHOT_TAGS = {'createdby': 'lambda'} # Dictionary of tags to apply to the created snapshots TAG_FILTERS = [{'Name': 'tag:Backup','Values': ['true']}] # Tags on which ec2 instance should get filter REGION = "ap-south-1" # AWS region in which the volumes exist def take_snapshots(volume, tags_kwargs): snapshot = volume.create_snapshot( Description='created by lambda' ) #snapshot = ec2.create_snapshot(VolumeId=volume,Description='Created by Lambda function ebs-snapshots') print(snapshot) if tags_kwargs: snapshot.create_tags(**tags_kwargs) def process_tags(): tags = [] tags_kwargs = {} # AWS allows 10 tags per resource if SNAPSHOT_TAGS and len(SNAPSHOT_TAGS) <= 10: for key, value in SNAPSHOT_TAGS.items(): tags.append({'Key': key, 'Value': value}) tags_kwargs['Tags'] = tags return tags_kwargs def print_summary(counts): print("\nSUMMARY:\n") print("Snapshots created: {}{}".format(counts,"")) print("-------------------------------------------\n") def lambda_handler(event, context): snap_count = 0 # List of devices that should be consider to take snapshot. Root volume is excluded here i.e. /dev/xvda or /dev/sda DEVICES = ['/dev/sdb', '/dev/sdc', '/dev/sde', '/dev/sdf', '/dev/sdg', '/dev/sdh', '/dev/sdi', '/dev/sdj', '/dev/sdk', '/dev/sdl', '/dev/sdm', '/dev/sdn', '/dev/sdo', '/dev/sdp', '/dev/sdq', '/dev/sdr', '/dev/sds', '/dev/sdt', '/dev/sdu', '/dev/sdv', '/dev/sdw', '/dev/sdx', '/dev/sdy', '/dev/sdz'] ec2 = resource("ec2", region_name=REGION) ec2_client = boto3.client('ec2') # Get information for all instances with tag "Backup:true" instances = ec2.instances.filter(Filters=TAG_FILTERS) # Filter all instances that have are attached to ec2 instances in "instances" for instance in instances: ec2_instance = ec2.Instance(instance.id) print("for instance:", ec2_instance ) volumes = ec2.volumes.filter(Filters=[{'Name': 'attachment.instance-id', 'Values': [ec2_instance.id]}, {'Name': 'attachment.device', 'Values': DEVICES} ]) #print(volumes) for tags in instance.tags: #print("inside for loop of instance.tags") if tags["Key"] == 'Name': SNAPSHOT_TAGS['Name'] = tags["Value"] # Take Backup for volume in volumes: tags_kwargs = process_tags() print("Taking snapshot..") take_snapshots(ec2.Volume(volume.id), tags_kwargs) snap_count += 1 print("at last summary") print_summary(snap_count)
