eks-lambda-drainer

eks-lambda-drainer is an Amazon EKS node drainer with AWS Lambda. If you provision spot instances or spotfleet in your Amazon EKS nodegroup, you can listen to the spot termination signal from CloudWatch Events 120 seconds in prior to the final termination process. By configuring this Lambda function as the CloudWatch Event target, eks-lambda-drainer will perform the taint-based eviction on the terminating node and all the pods without relative toleration will be evicted and rescheduled to another node - your workload will get very minimal impact on the spot instance termination.

Installation

Install SAM CLI and go dep

1. execute dep ensure -vto make sure all packages required can be downloaded to local

2. just type make to buiild the main.zip for Lambda

3. sam package to package the lambda bundle

   sam package \
     --template-file sam.yaml \
     --output-template-file sam-packaged.yaml \
     --s3-bucket pahud-tmp
   

   (change pahud-tmp to your temporary S3 bucket name)

4. sam deploy to deploy to AWS Lambda

   sam deploy \
   > --template-file sam-packaged.yaml \
   > --stack-name eks-lambda-drainer \
   > --capabilities CAPABILITY_IAM
   

Add Lambda Role into ConfigMap

Read Amazon EKS document about how to add an IAM Role to the aws-auth ConfigMap.

Edit the aws-auth ConfigMap by

kubectl edit -n kube-system configmap/aws-auth

And insert rolearn, groups and username into the mapRoles, make sure the groups contain system:masters

You can get the rolearn from the output tab of cloudformation console.

In Actions

try kubectl describe this node and see the Taints on it

TODO

• package the Lambda function in AWS SAM format
• publish to AWS Serverless Applicaton Repository
• ASG/LifeCycle integration #2
• add more samples

FAQ

Do I need to specify the Amazon EKS cluster name in Lambda?

ANS: No, eks-lambda-drainer will determine the Amazon EKS cluster name from the EC2 Tags(key=kubernetes.io/cluster/{CLUSTER_NAME} with value=owned). You just need single Lambda function to handle all spot instances from different nodegroups from different Amazon EKS clusters.