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Usage with kind

You can try kube-green locally to test how it works.

In this tutorial, we will use kind to run a Kubernetes cluster locally, but you can use any other alternatives.

Install tools​

To follow this guide, you should have kubectl and kind installed locally.

Now you have all the tools needed, let's go!

Create a cluster​

Creating a cluster with kind is very simple, just run:

kind create cluster --name kube-green

Install the cert-manager​

With this command, the latest release of cert-manager will be installed.

kubectl apply -f https://github.com/jetstack/cert-manager/releases/latest/download/cert-manager.yaml

You can check the correct cert-manager deployment by verifying that all the pods are running correctly.

kubectl -n cert-manager get pods

Install kube-green​

Install kube-green with the default static install. Click here to see the different install methods supported.

Install kube-green with this command:

kubectl apply -f https://github.com/kube-green/kube-green/releases/latest/download/kube-green.yaml

This command creates a kube-green namespace and deploys a kube-green-controller-manager. You can check that the pod is running correctly:

kubectl -n kube-green get pods

Test usage​

To test kube-green, we will create a namespace with some active pods handled by Deployments. At this point, set the CRD and observe the changes in the namespace.

Setup namespace​

Create a namespace sleepme and install two simple Deployments with replicas set to 1 and another with replicas more than 1. In this tutorial, we use the davidebianchi/echo-service service.

kubectl create ns sleepme
kubectl -n sleepme create deploy echo-service-replica-1 --image=davidebianchi/echo-service
kubectl -n sleepme create deploy do-not-sleep --image=davidebianchi/echo-service
kubectl -n sleepme create deploy echo-service-replica-4 --image=davidebianchi/echo-service --replicas 4

You should have 6 pods running in the namespace.

kubectl -n sleepme get pods

The output should be something like:

NAME                                      READY   STATUS    RESTARTS   AGE
do-not-sleep-5b88f75df7-wmms2             1/1     Running   0          107s
echo-service-replica-1-6845b564c6-zvt7x   1/1     Running   0          102s
echo-service-replica-4-5f97664965-22kmw   1/1     Running   0          115s
echo-service-replica-4-5f97664965-2x9dj   1/1     Running   0          115s
echo-service-replica-4-5f97664965-6wpb7   1/1     Running   0          115s
echo-service-replica-4-5f97664965-pcl6q   1/1     Running   0          115s

Setup kube-green in application namespace​

To set up kube-green, the SleepInfo resource must be created in the sleepme namespace.

The desired configuration is:

  • echo-service-replica-1 sleeps
  • all replicas of echo-service-replica-4 sleep
  • do-not-sleep pod remains unchanged

At sleep time, echo-service-replica-1 will wake up with 1 replica, and echo-service-replica-4 will wake up with 4 replicas as before.
So, after sleep, we expect 1 pod active, and after wake up, we expect 6 pods active.

The SleepInfo can be written in this way to sleep every 5th minute and wake up every 7th minute.

apiVersion: kube-green.com/v1alpha1
kind: SleepInfo
metadata:
  name: sleep-test
spec:
  weekdays: "*"
  sleepAt: "*:*/5"
  wakeUpAt: "*:*/7"
  excludeRef:
    - apiVersion: "apps/v1"
      kind:       Deployment
      name:       do-not-sleep

It is possible to change the configuration in a more realistic way by adding a fixed interval. So, if now it's 16:00 in Italy, for example, we could set it to sleep at 16:03 and wake up at 16:05.

apiVersion: kube-green.com/v1alpha1
kind: SleepInfo
metadata:
  name: sleep-test
spec:
  weekdays: "*"
  sleepAt: "16:03"
  wakeUpAt: "16:05"
  timeZone: "Europe/Rome"
  excludeRef:
    - apiVersion: "apps/v1"
      kind:       Deployment
      name:       do-not-sleep

So, copy and modify the configuration file you want in a file called sleepinfo.yaml, and apply it to the sleepme namespace

kubectl -n sleepme apply -f sleepinfo.yaml

And watch the pods in the namespace. If you have configured the watch command, you could use

watch kubectl -n sleepme get pods

otherwise

kubectl -n sleepme get pods -w

At the time set in the configuration for sleep, all pods except the do-not-sleep should sleep.

NAME                            READY   STATUS    RESTARTS   AGE
do-not-sleep-5b88f75df7-wmms2   1/1     Running   0          13m

At the time set in the configuration for wake up, all pods will wake up with the initial number of replicas

NAME                                      READY   STATUS    RESTARTS   AGE
do-not-sleep-5b88f75df7-wmms2             1/1     Running   0          16m
echo-service-replica-1-6845b564c6-hbjv9   1/1     Running   0          92s
echo-service-replica-4-5f97664965-42xbs   1/1     Running   0          92s
echo-service-replica-4-5f97664965-9wbqn   1/1     Running   0          92s
echo-service-replica-4-5f97664965-c4kzf   1/1     Running   0          92s
echo-service-replica-4-5f97664965-n72tr   1/1     Running   0          92s