5.3 Cheatsheet

https://killercoda.com/isislab/scenario/exam-playground

---[01] Resources that are namespaced

kubectl api-resources

---[02 Get namespaces ]

kubectl get namespaces

---[03] Get description of namespaces

kubectl describe ns default

---[04] Get description of services in namespaces

kubectl get svc --namespace kube-system

---[05] Create a namespace

git clone https://github.com/nigelpoulton/TheK8sBook.git #clone repo

cd TheK8sBook/namespaces

kubectl create ns hydra #imperative

kubectl get ns

cat shield-ns.yml

Here are data in shield-ns.yml

kind: Namespace

apiVersion: v1

metadata:

name: shield

labels:

env: marvel

kubectl apply -f shield-ns.yml

kubectl get ns # see namespaces

kubectl delete ns hydra # for other examples

kubectl get ns

kubectl config set-context --current --namespace shield # set kubectl for a specific Namespace

kubectl get pods #empty

---[06] Get description of services in namespaces

less app.yml

kubectl apply -f app.yml #warning

kubectl get pods -n shield # take a look at the pods there

kubectl get pods # it is enough (as the current is set to shield)

kubectl get svc -n shield # external-up is always <pending>

kubectl describe services the-bus # to get the CLUSTER-IP (EXTERNAL-IP is always pending) as xxx.xxx.xxx.xxx

curl xxx.xxx.xxx.xxx:8080 # you get the AOS answer

kubectl delete ns shield # deletes everything inside ns

kubectl get ns # in another terminal to see it terminating

kubectl config set-context --current --namespace default # reset current to default

---[07] Sidecar initialization

cd ~/TheK8sBook/pods

vim sidecarpod.yml

On the browser

1: Fork in your Github https://github.com/nigelpoulton/ps-sidecar and call it my-ps-sidecar

---[08] Sidecar running

2. Update the YAML file with the URL of your forked repo

vim sidecarpod.yml

Change the repository in GIT_SYNC_REPO from

value: https://github.com/nigelpoulton/ps-sidecar.git

To

value: https://github.com/vitsca/my-ps-sidecar.git

vitsca/my-ps-sidecar/

3. Deploy the app

kubectl apply -f sidecarpod.yml

kubectl get pods # to see them

kubectl describe pods # to see them

4. Connect to the app and see it display This is version 1.0

kubectl get svc

Get the address CLUSTER-IP xxx.xxx.xxx.xxx

curl xxx.xxx.xxx.xxx

see that it is indeed answering 1.0

---[09] Sidecar changed the content

5. Make a change to your fork of the GitHub repo

---[10] Make a new call and see how to sidecar updated the data

6. Call again the sidecar nginx and see it changed

curl xxx.xxx.xxx.xxx