AWS Trusted Advisor is an important tool which provides more than 50 checks across four different categories Cost Optimization, Performance, Security & Fault Tolerance (at the moment of writing this post). But I have noticed that this is not being used more extensively considering the importance of it. Hence I created couple of lambda functions which shall be configured to run on daily basis to refresh the checks and create summary of all the checks and send an email. Read more

EBS snapshot as backup mechanism is a very common practice and it also has been defined in Backup and Recovery section of EC2 best practices. If you have read my another article Save AWS costs by scheduled start and stop of EC2 instances, similar approach will be used in creating Snapshots too. Using JSON in EC2 Tags enables us to provide granular configuration details. Create an EC2 tag with name as backup and value with details containing time to take backup and retention period. Read more

Cross-Region Replication for Amazon S3 was introduced last year which enables replicating objects from a S3 bucket to a different S3 bucket located in different region (it can be same/different AWS account). It’s one of the most sought after feature for long time but it doesn’t solve some of the scenarios as defined below. Synchronizing to a bucket in same region. Synchronizing to multiple destination buckets. Object ACLs needs to be set at the source bucket hence multiple different ACLs needs to be set when copying across different accounts. Read more

Blue/Green deployment is a well-known method to deploy an application without any downtime. Performing DNS switch is one of the very common techniques to achieve this. Using DNS switch has a minor issue with DNS caching which might take some time for DNS change to be propagated. Apart from DNS switch, AWS gives us two different options to switch the stacks. One is to have single ELB and swap it across auto-scaling group and another is switching the launch configuration of the auto-scaling group. Read more

CloudFormation uses a pre-signed S3 URL to receive the response back from the custom resources managed by it. There are few blue prints available for Node.js Lambda custom resources but nothing available for python yet. Hence I created this simple function which shall be used to send the response back to CFN custom resource by performing PUT request to the pre-signed S3 URL. import json import requests def lambda_handler(event, context): responseStatus = 'SUCCESS' responseData = {} if event['RequestType'] == 'Delete': sendResponse(event, context, responseStatus, responseData) responseData = {'Success': 'Test Passed. Read more