Updated creator to get all variables from Tags. Added functionality to exclude individual Volumes attached to an Instance from SnapShots and added support for off-site tag. Configured description to use Volume Name where specified.

Author: Dave Osment

ebs-snapshot-creator.py

@@ -1,81 +1,141 @@
 import boto3
 import collections
 import datetime
-
-region = 'us-west-2'    # region we're running in (should be changed to be auto-determined 
+import os
 
 ec = boto3.client('ec2')
 
 def lambda_handler(event, context):
-    reservations = ec.describe_instances(
+	
+	# Get Current Region
+    aws_region = os.getenv('AWS_REGION')
+    
+    # Get Retention Period From Environment Variable Or Assume Default If Not Specified
+    retention_days = int(
+        os.getenv(
+            'RETENTION_DAYS', 
+            7
+        )
+    )
+    
+    print "Setting SnapShot retention period To %s days" % (retention_days)
+	
+	# Determine Which Instances To SnapShot
+    instances = ec.describe_instances(
         Filters=[
             { 'Name': 'tag:Backup', 'Values': ['Yes'] },
         ]
     ).get(
         'Reservations', []
     )
+    
+    print "Found %d instances that need backing up" % len(instances[0]['Instances'])
 
-    instances = sum(
-        [
-            [i for i in r['Instances']]
-            for r in reservations
-        ], [])
-
-    print "Found %d instances that need backing up" % len(instances)
-
+    # Initialise Dictionary Objects To Store Tags In
     to_tag = collections.defaultdict(list)
 
-    for instance in instances:
-        try:
-            retention_days = [
-                int(t.get('Value')) for t in instance['Tags']
-                if t['Key'] == 'Retention'][0]
-        except IndexError:
-            retention_days = 7
+    # Iterate Over Each Instance & SnapShot Volumes Not Explicitly Excluded From Backups
+    for instance in instances[0]['Instances']:
 
+        # List All Volumes Attached To The Instance
         for dev in instance['BlockDeviceMappings']:
+            
+            # Set Variable Defaults
+            snapshot_required = True
+            volume_name = None
+            
             if dev.get('Ebs', None) is None:
                 continue
             vol_id = dev['Ebs']['VolumeId']
             dev_name = dev['DeviceName']
-            print "\tFound EBS volume %s (%s) on instance %s" % (
-                vol_id, dev_name, instance['InstanceId'])
-
-            # figure out instance name if there is one
-            instance_name = ""
-            for tag in instance['Tags']:
-                if tag['Key'] != 'Name':
-                    continue
-                else:
-                    instance_name = tag['Value']
 
-            description = '%s - %s (%s)' % ( instance_name, vol_id, dev_name )
-
-            # trigger snapshot
-            snap = ec.create_snapshot(
-                VolumeId=vol_id, 
-                Description=description
+            # Get a Volume Object Based Upon Volume ID
+            volume = ec.describe_volumes(
+                VolumeIds=[vol_id,]
+            )
+            
+            vol = volume['Volumes'][0]
+            if 'Tags' in vol:
+                for tag in vol['Tags']:
+                    
+                    # Determine If Volume Has 'Backup' Flag Set To 'No' & Exclude From SnapShot If It Does
+                    if tag['Key'] == 'Backup' and tag['Value'] == 'No':
+                        snapshot_required = False
+                       
+                    # Determine If Volume Has a Name Specified     
+                    if tag['Key'] == 'Name':
+                        volume_name = tag['Value']
+                        
+            # Exit This Loop If SnapShot Not Required
+            if snapshot_required == False:
+                print "\tIgnoring EBS volume %s (%s) on instance %s - 'Backup' Tag set to 'No'" % (
+                    vol_id, 
+                    dev_name, 
+                    instance['InstanceId']
                 )
 
-            if (snap):
-                print "\t\tSnapshot %s created in %s of [%s]" % ( snap['SnapshotId'], region, description )
-            to_tag[retention_days].append(snap['SnapshotId'])
-            print "\t\tRetaining snapshot %s of volume %s from instance %s (%s) for %d days" % (
-                snap['SnapshotId'],
-                vol_id,
-                instance['InstanceId'],
-                instance_name,
-                retention_days,
-            )
+            else:
+                print "\tFound EBS volume %s (%s) on instance %s - Proceeding with SnapShot" % (
+                    vol_id, 
+                    dev_name, 
+                    instance['InstanceId']
+                )
+    
+                # Determine EC2 Instance Name (If Present)
+                instance_name = ""
+                for tag in instance['Tags']:
+                    if tag['Key'] != 'Name':
+                        continue
+                    else:
+                        instance_name = tag['Value']
+                        
+                # Determine SnapShot Description (Use Volume Name If Specified)
+                if volume_name == None:
+                    description = '%s - %s (%s)' % ( 
+                        instance_name, 
+                        vol_id, 
+                        dev_name 
+                    )
+                else:
+                    description = volume_name
+                    
+                # Trigger SnapShot
+                snap = ec.create_snapshot(
+                    VolumeId=vol_id, 
+                    Description=description
+                    )
+                
+                if (snap):
+                    print "\t\tSnapshot %s created in %s of [%s]" % ( 
+                        snap['SnapshotId'], 
+                        aws_region, 
+                        description 
+                    )
+                
+                # Tag The SnapShot To Facilitate Later Automated Deletion
+                to_tag[retention_days].append(snap['SnapshotId'])
+                
+                print "\t\tRetaining snapshot %s of volume %s from instance %s (%s) for %d days" % (
+                    snap['SnapshotId'],
+                    vol_id,
+                    instance['InstanceId'],
+                    instance_name,
+                    retention_days,
+                )                
 
     for retention_days in to_tag.keys():
         delete_date = datetime.date.today() + datetime.timedelta(days=retention_days)
         delete_fmt = delete_date.strftime('%Y-%m-%d')
-        print "Will delete %d snapshots on %s" % (len(to_tag[retention_days]), delete_fmt)
+        print "Will delete %d snapshots from %s on %s" % (
+            len(to_tag[retention_days]),
+            aws_region,
+            delete_fmt
+        )
+        
         ec.create_tags(
             Resources=to_tag[retention_days],
             Tags=[
                 { 'Key': 'DeleteOn', 'Value': delete_fmt },
                 { 'Key': 'Type', 'Value': 'Automated' },
             ]
-        )
+        )