If you get stuck anywhere, try to find help here or ask the teacher: https://support.nine.ch/categories/managed-gke
In this exercise you will get familliar with kubectl since it is really important to master. Before we begin, take a quick look at the kubectl cheat sheet: https://kubernetes.io/docs/reference/kubectl/cheatsheet/
We covered what a kubernetes namespace is in the theory part of the course. If you want a reminder you can read about namespaces here: https://kubernetes.io/docs/concepts/overview/working-with-objects/namespaces/
Kubernetes comes with a couple of default namespaces. Try to list them with kubectl. Hint: use the kubectl get command. You can always add a -h flag to get some help.
Try to list the namespaces with the following command:
$ kubens
You will see that you are in the default namespace. If you try to list anything in this namespace, you wil notice that you dont have the permissions.
$ kubectl get all
Lets create our own namespace. This is a shared cluster, so please use the following convention: academy- firstname i.e. academy-max We need to use the kubectl create command for this. Hint: Use the -h flag for a example.
After you created the namespace try to see the details using the kubectl describe command. Finally use kubens and set it to your namespace you just created:
$ kubens <your namespace>
Lets say that this namespace you just created is a development enviroment of our fictional app called "cool-app".
It would maybe make sense to label that namespace. For this we need to edit the namespace using the kubectl edit command.
Add the following labels:
env: dev
app: cool-app
Your namespace should already have one label. Put these two under it. If you need help you can find some examples here: https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#syntax-and-character-set
If you do a kubectl get all, you obviously wont see anything, so lets create a pod!
We will need the kubectl run command for this. Again, like with every command check out kubectl run -h! Use the following parameters: --image=nginx --port=80 --restart=Never
List the detail of the pod with the get command. Maybe try out the flag -o wide! Also describe the pod!
Now lets see if we can see the logs of the container running in our newly created pod.
Use the kubectl logs command!
Optional: If you wanna maybe see the k8s dashboard in action, you can open runway again and in the Services tab, you can follow the link of to the k8s dashboard. Set your namespace there and check out the pod.
Now lets delete the pod. Use the delete command! Do a get command afterwards. What happens?
We have created now a pod directly, but usually we dont wanna create it directly. Lets create a deployment! Use the k8s.gcr.io/echoserver:1.4 image.
When you create a Deployment, 3 ressources are deployed. Deployments, ReplicaSet and Pods. Check them all out. Make sure to understand what happens!
When your app becomes more popular, you will need to scale. Luckily that is quite easy with k8s. When you described the deployment and the replicaset, you might have seen the replica field. Scale the deployment to 3 or more replicas and check out what happens to three ressources you described above. Use the scale kubectl command!
# 9
K8s is supposed to be self healing, right? Lets prove it. Delete any of the pods of the deployment. What happens? Checkout the events aswell the events with kubectl get events.
Delete the deployment
Until now you have created and deleted ressources using the kubectl commands. Now we are gonna use the actual ressource definitions, how you would do it in the real world.
Check out this file templates/1/11.yaml
You will see a deployment ressource definition. Describe each line and write it down on the right behind the comment.
Create a deployment out of the file above. Use the kubectl apply command.
Change the replica count in the file and apply it again. What happens?
Delete the the deployment.
You can find the solutions here solutions/1.md.