Kubernetes Custom Metrics Adapter for Kubernetes

An implementation of the Kubernetes Custom Metrics API and External Metrics API for AWS CloudWatch metrics.

This adapter allows you to scale your Kubernetes deployment using the Horizontal Pod Autoscaler (HPA) with metrics from AWS CloudWatch.

This project is currently in Alpha status, use at your own risk.

Prerequsites

This adapter requires the following permissions to access metric data from Amazon CloudWatch.

• cloudwatch:GetMetricData
• cloudwatch:GetMetricStatistics
• cloudwatch:ListMetrics

You can create an IAM policy using this template, and attach it to the role if you are using kube2iam.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "cloudwatch:GetMetricData",
                "cloudwatch:GetMetricStatistics",
                "cloudwatch:ListMetrics"
            ],
            "Resource": "*"
        }
    ]
}

Deploy

Requires a Kubernetes cluster with Metric Server deployed, Amazon EKS cluster is fine too.

Now deploy the adapter to your Kubernetes cluster.

$ kubectl apply -f https://raw.githubusercontent.com/awslabs/k8s-cloudwatch-adapter/master/deploy/adapter.yaml
namespace/custom-metrics created
clusterrolebinding.rbac.authorization.k8s.io/k8s-cloudwatch-adapter:system:auth-delegator created
rolebinding.rbac.authorization.k8s.io/k8s-cloudwatch-adapter-auth-reader created
deployment.apps/k8s-cloudwatch-adapter configured
clusterrolebinding.rbac.authorization.k8s.io/k8s-cloudwatch-adapter-resource-reader created
serviceaccount/k8s-cloudwatch-adapter created
service/k8s-cloudwatch-adapter created
apiservice.apiregistration.k8s.io/v1beta1.custom.metrics.k8s.io created
apiservice.apiregistration.k8s.io/v1beta1.external.metrics.k8s.io created
clusterrole.rbac.authorization.k8s.io/k8s-cloudwatch-adapter:custom-metrics-reader created
clusterrole.rbac.authorization.k8s.io/k8s-cloudwatch-adapter:external-metrics-reader created
clusterrole.rbac.authorization.k8s.io/k8s-cloudwatch-adapter-resource-reader created
clusterrolebinding.rbac.authorization.k8s.io/k8s-cloudwatch-adapter:custom-metrics-reader created
clusterrolebinding.rbac.authorization.k8s.io/k8s-cloudwatch-adapter:external-metrics-reader created
customresourcedefinition.apiextensions.k8s.io/externalmetrics.metrics.aws created
clusterrole.rbac.authorization.k8s.io/k8s-cloudwatch-adapter:crd-metrics-reader created
clusterrolebinding.rbac.authorization.k8s.io/k8s-cloudwatch-adapter:crd-metrics-reader created

This creates a new namespace custom-metrics and deploys the necessary ClusterRole, Service Account, Role Binding, along with the deployment of the adapter.

Verifying the deployment

Next you can query the APIs to see if the adapter is deployed correctly by running:

$ kubectl get --raw "/apis/custom.metrics.k8s.io/v1beta1" | jq .
{
  "kind": "APIResourceList",
  "apiVersion": "v1",
  "groupVersion": "custom.metrics.k8s.io/v1beta1",
  "resources": [
  ]
}

and

$ kubectl get --raw "/apis/external.metrics.k8s.io/v1beta1" | jq.
{
  "kind": "APIResourceList",
  "apiVersion": "v1",
  "groupVersion": "external.metrics.k8s.io/v1beta1",
  "resources": [
  ]
}

Deploying the sample application

There is a sample SQS application provided in this repository for you to test how the adapter works. Refer to this guide

License

This library is licensed under the Apache 2.0 License.

Issues

Report any issues in the Github Issues