Kubernetes Cloud Controller Manager for Cloud.dk

clouddk-cloud-controller-manager is a Kubernetes Cloud Controller Manager implementation (or out-of-tree cloud-provider) for Cloud.dk.

WARNING: This project is under active development and should be considered alpha.

Introduction

External cloud providers were introduced as an Alpha feature in Kubernetes 1.6 with the addition of the Cloud Controller Manager binary. External cloud providers are Kubernetes (master) controllers that implement the cloud-provider specific control loops required for Kubernetes to function.

clouddk-cloud-controller-manager is one such provider and is designed to work with Kubernetes clusters running on Cloud.dk. It enables these clusters to retrieve metadata for nodes and create services of type LoadBalancer.

Preparation

In order to enable support for the controller, a flag must be set on the kubelet component.

In case the cluster was deployed with kubeadm, simply edit /etc/default/kubelet and add --cloud-provider=external to KUBELET_EXTRA_ARGS.

Alternatively, you can add the following fragment to a kubeadm configuration file:

nodeRegistration:
  kubeletExtraArgs:
    cloud-provider: "external"

Installation

Follow these simple steps in order to install the controller:

1. Ensure that kubectl is configured to reach the cluster

2. Retrieve the API key from https://my.cloud.dk/account/api-key and encode it

   echo "CLOUDDK_API_KEY: '$(echo "the API key here" | base64 | tr -d '\n')'"

3. Create a new SSH key pair

   rm -f /tmp/clouddk_ssh_key* \
       && ssh-keygen -b 4096 -t rsa -f /tmp/clouddk_ssh_key -q -N "" \
       && echo "CLOUDDK_SSH_PRIVATE_KEY: '$(cat /tmp/clouddk_ssh_key | base64 | tr -d '\n' | base64 | tr -d '\n')'" \
       && echo "CLOUDDK_SSH_PUBLIC_KEY: '$(cat /tmp/clouddk_ssh_key.pub | base64 | tr -d '\n' | base64 | tr -d '\n')'"

4. Create a new file called config.yaml with the following contents:

   apiVersion: v1
   kind: Secret
   metadata:
     name: clouddk-cloud-controller-manager-config
     namespace: kube-system
   type: Opaque
   data:
     CLOUDDK_API_ENDPOINT: 'aHR0cHM6Ly9hcGkuY2xvdWQuZGsvdjEK'
     CLOUDDK_API_KEY: 'The encoded API key generated in step 2'
     CLOUDDK_SSH_PRIVATE_KEY: 'The encoded private SSH key generated in step 3'
     CLOUDDK_SSH_PUBLIC_KEY: 'The encoded public SSH key generated in step 3'

5. Create the secret in config.yaml using kubectl

   kubectl apply -f ./config.yaml

6. Deploy the controller using kubectl

   kubectl apply -f https://raw.githubusercontent.com/danitso/clouddk-cloud-controller-manager/master/deployment.yaml

   It may be necessary to download the file and modify it before deploying the controller, if the default cluster settings do not match the settings of a particular cluster.

7. Verify that clouddk-cloud-controller-manager pods are being created and wait for them to reach a Running state

   kubectl get pods -l k8s-app=clouddk-cloud-controller-manager -n kube-system

Features

LoadBalancer

The clouddk-cloud-controller-manager plugin adds support for Load Balancers based on HAProxy. These can be created just like regular Load Balancers. However, the following annotations can be used to modify the default configuration:

kubernetes.cloud.dk/load-balancer-algorithm

The load balancing algorithm.

Options: leastconn, roundrobin and source

Default: roundrobin

kubernetes.cloud.dk/load-balancer-client-timeout

The number of seconds the Load Balancer will allow a client to idle for

Range: 1-86400

Default: 30

kubernetes.cloud.dk/load-balancer-connection-limit

The connection limit.

Range: 1-20000

Default: 1000

kubernetes.cloud.dk/load-balancer-enable-proxy-protocol

Whether to enable the PROXY protocol.

Options: true and false

Default: false

kubernetes.cloud.dk/load-balancer-health-check-interval

The number of seconds between between two consecutive health checks.

Range: 3-300

Default: 3

kubernetes.cloud.dk/load-balancer-health-check-threshold-healthy

The number of times a health check must pass for a backend to be marked "healthy" for the given service and be re-added to the pool.

Range: 2-10

Default: 5

kubernetes.cloud.dk/load-balancer-health-check-threshold-unhealthy

The number of times a health check must fail for a backend to be marked "unhealthy" and be removed from the pool for the given service.

Range: 2-10

Default: 3

kubernetes.cloud.dk/load-balancer-health-check-timeout

The number of seconds the Load Balancer will wait for a response until marking a health check as failed.

Range: 3-300

Default: 5

kubernetes.cloud.dk/load-balancer-server-timeout

The number of seconds the Load Balancer will allow a server to idle for.

Range: 1-86400

Default: 60