November 29, 2015

Executing Ruby code in AWS Lambda

AWS Lambda supports only Java, JavaScript & Python at the time of writing this post. I was wondering whether I can exploit the Lambda to execute chef’s knife commands on it since Lambda runs on a Linux container. Using simple python function I have identified that the code of the Lambda function gets copied to /var/task and executed from there. I decided to custom build ruby as embedded platform similar to how chef-client or chefdk are distributed. Read more

November 27, 2015

Automated cross account DNS management through CFN and API access through API gateway

It’s a general best practice to manage all DNS entries in Route53 in a centralized AWS account. In that case it is difficult to automate the DNS record creation/deletion based on resources created in another AWS account using CloudFormation. CloudFormation doesn’t yet have the capability to create resources in a different AWS account. Combining IAM role delegation, AWS Lambda & CFN Custom resources provides us a solution. I have extended the same solution by exposing the Lambda function through API gateway which provides a powerful mechanism. Read more

November 22, 2015

Obtain AMI Id from name to be used in CFN

In most cases we create custom AMI’s for various reasons like OS hardening, installing and configuring additional software, etc. If you use single AWS account to create the AMI’s and share it with other AWS accounts and use that as part of CloudFormation template, it is required to pass the new AMI Id every time. AWS Lambda comes handy for easy and elegant solution to get the latest AMI Id based on the AMI name and owner. Read more

November 15, 2015

Save AWS costs by scheduled start and stop of EC2 instances

Most of the AWS resources are billed on per-hour basis which provides us an opportunity to save cost based on the usage pattern. Especially in case of Dev/Test environment, we need them only during the working days and working hours. By using AWS Lambda function (python) in combination with EC2 instance tags, scheduled start or stop can be achieved with few lines of code. Advantages of using AWS Lambda: For 128MB memory we get 3,200,000 seconds free tier usage per month in AWS Lambda which will be more than enough for this function. Read more

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