A lambda function that will copy EC2 tags to all related Volumes and Network Interfaces. A full writeup can be found on my site http://mlapida.com/thoughts/tagging-and-snapshotting-with-lambda

EC2-Tag-Assets-Lambda.py

from __future__ import print_function

import json
import boto3
import logging

#setup simple logging for INFO
logger = logging.getLogger()
logger.setLevel(logging.ERROR)

#define the connection region
ec2 = boto3.resource('ec2', region_name="us-west-2")

#Set this to True if you don't want the function to perform any actions
debugMode = False

def lambda_handler(event, context):
    #List all EC2 instances
    base = ec2.instances.all()

    #loop through by running instances
    for instance in base:
        
        #Tag the Volumes
        for vol in instance.volumes.all():
            #print(vol.attachments[0]['Device'])
            if debugMode == True:
                print("[DEBUG] " + str(vol))
                tag_cleanup(instance, vol.attachments[0]['Device'])
            else:
                tag = vol.create_tags(Tags=tag_cleanup(instance, vol.attachments[0]['Device']))
                print("[INFO]: " + str(tag))
        
        #Tag the Network Interfaces
        for eni in instance.network_interfaces:
            #print(eni.attachment['DeviceIndex'])
            if debugMode == True:
                print("[DEBUG] " + str(eni))
                tag_cleanup(instance, "eth"+str(eni.attachment['DeviceIndex']))
            else:
                tag = eni.create_tags(Tags=tag_cleanup(instance, "eth"+str(eni.attachment['DeviceIndex'])))
                print("[INFO]: " + str(tag))
    
#------------- Functions ------------------
#returns the type of configuration that was performed    
        
def tag_cleanup(instance, detail):
    tempTags=[]
    v={}
    
    for t in instance.tags:
        #pull the name tag
        if t['Key'] == 'Name':
            v['Value'] = t['Value'] + " - " + str(detail)
            v['Key'] = 'Name'
            tempTags.append(v)
        #Set the important tags that should be written here  
        elif t['Key'] == 'Application Owner':
            print("[INFO]: Application Owner Tag " + str(t))
            tempTags.append(t)    
        elif t['Key'] == 'Cost Center':
            print("[INFO]: Cost Center Tag " + str(t))
            tempTags.append(t)  
        elif t['Key'] == 'Date Created':
            print("[INFO]: Date Created Tag " + str(t))
            tempTags.append(t)  
        elif t['Key'] == 'Requestor':
            print("[INFO]: Requestor Tag " + str(t))
            tempTags.append(t)  
        elif t['Key'] == 'System Owner':
            print("[INFO]: System Owner Tag " + str(t))
            tempTags.append(t)
        else:
            print("[INFO]: Skip Tag - " + str(t))
    
    print("[INFO] " + str(tempTags))
    return(tempTags)

Policy-EC2Tags.json

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "ec2:Describe*",
        "ec2:CreateTags",
        "tag:getResources",
        "tag:getTagKeys",
        "tag:getTagValues",
        "tag:addResourceTags",
        "tag:removeResourceTags"
      ],
      "Resource": "*"
    }
  ]
}

Policy-LambdaBasicExec.json

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "logs:CreateLogGroup",
        "logs:CreateLogStream",
        "logs:PutLogEvents"
      ],
      "Resource": "arn:aws:logs:*:*:*"
    }
  ]
}