Kubernetes Exercises

Notes

Try the following exercises by using imperative commands instead of starting off with yaml declaration files.
Setup ~/.vimrc file with the following: - set ts=2 sw=2 - set number - set expandtab

Exercises

Ex 1: Deploy a pod named nginx-pod using the nginx:alpine image.

Ex 2: Deploy a redis pod using the redis:alpine image with the labels set to tier=db.

Ex 3: Create a service redis-service to expose the redis application within the cluster on port 6379

Ex 4: Create a deployment named webapp using the image kodekloud/webapp-color with 3 replicas.

Ex 5: How do you label nodes and specify pods to only use nodes with that label?

Ex 6: Create a deployment from the nginx image with 3 replicas affiliated to node deb-k8node02 which is labelled colour=red

Ex 7: Create a https enabled nginx depoyment, creating the https keys, placing them into the ng-secret secrets, similarly creating the required nginx configuration to support this with the following attributes:

Image: nginx:alpine

Web host name: nginx.bigtom.local

Requests for .2 CPU and label app=nginx

Expose container port 443 for https only

Create the following nginx configuration into the ng-config configuration map:
server {
    listen                80;
    listen                443 ssl;
    server_name           nginx.bigtom.local;

    ssl_certificate       certs/https.cert;
    ssl_certificate_key   certs/https.key;
    ssl_protocols         TLSv1 TLSv1.1 TLSv1.2;
    ssl_ciphers           HIGH:!aNULL:!MD5;

    location / {
        root   /usr/share/nginx/html;
        index  index.html index.htm;
    }
}

Answers

Ans 1:

$ kubectl run --generator=run-pod/v1 nginx-pod --image=nginx:alpine

Ans 2:

$ kubectl run --generator=run-pod/v1 redis --image=redis --dry-run -o yaml > redis.yaml
Now edit the redis.yaml file and add tier: db under the labels: dictionary.

Ans 3:

$ kubectl expose pod/redis --name redis-service --port=6379

Ans 4:

$ kubectl create deploy webapp --image=kodekloud/webapp-color --dry-run -o yaml > webapp.yaml
Now, edit the webapp.yaml file and create a line replicas=3 and save it.
$ kubectl apply -f webapp.yaml

Ans 5:

$ kubectl label nodes deb-k8node02 gpu=nvidia to label a node.

spec:
  containers:
  - name: myapp
    image: nginx
  nodeSelector:
    gpu: nvidia

The block above shows how the pod specifications should be created in yaml to use the node deb-k8node02 which has the label gpu=nvidia.

Ans 7: - Create the private key: $ openssl genrsa -out https.key 2048 - Create the https certificate: $ openssl req -new -x509 -key https.key -out https.cert -days 365 -subj /CN=nginx.bigtom.local - Create the ng-secret secret from the https keys: $ kubectl create secret generic ng-secret --from-file=https.key --from-file=https.cert - Create the config map, deployment and service from a yaml file.

A place to practice Kubernetes

URL: https://labs.play-with-k8s.com

Initialise the master node with: - kubeadm init –apiserver-advertise-address $(hostname -i)

Initialise cluster networking with: - kubeectl apply -n kube-system -f “https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d ‘n’)”

Untainting a node to get it to schedule: - kubectl taint nodes node1 node-role.kubernetes.io/master:NoSchedule-