I was looking for a way to automatically set labels to a Kubernetes node based on the tags the EC2 has.

I wrote a small application that uses an informer to take action every time a new node joins the cluster. If the node has the label failure-domain.beta.kubernetes.io/region it is able to look for the instance tags from AWS. Specifically it looks for instance tags like:

kubernetes/aws-labeler/label/type=ci

If the EC2 has this tag the Kubernetes node will have a label called

awslabeler.com/type=ci

That you can use to schedule your pods.

Other than labels it also support taints:

AWS EC2 tags like:

kubernetes/aws-labeler/taint/type=ci:NoExecute

Will become:

awslabeler.com/type=ci:NoExecute

Build

$ make docker

Creates an image

Deploy to Kubernetes

1. You need to create a service account for this pod becauase it needs access to the nodes resources. Get, watch, update is enough.
2. You need to give access to AWS so you need to configure a IAM role for your pod, or share a credential file or via envvar.

Try locally

It really depends on your setup as usual but in my case I use this command:

AWS_PROFILE=my-credentials-profile KUBECONFIG=/home/myhome/.kube/config go run cmd/aws-node-labeler/main.go