1 Deploy Applications on Kubernetes¶

Objective:

Review process of creating NameSpaces
Review process of changing Context
Review process of creating K8s:
- Services
- Labels, Selectors
- Deployments
- Rolling Updates

1.1 Development Tools¶

Note

This steps is optional

Step 1 Choose one of the following option to develop the YAML manifests:

Option 1: You can develop in Google Cloud Shell Editor

Option 2: You can also develop locally on your laptop using VCScode. We recommend to use it in conjunction with VSC YAML extension from Redhat

Option 3: Use your preferred text editor on Linux VM (vim, nano).

2.1 Create GKE Cluster¶

Step 1 Enable the Google Kubernetes Engine API.

gcloud services enable container.googleapis.com

Step 2 From the cloud shell, run the following command to create a cluster with two nodes:

gcloud container clusters create k8s-concepts \
--zone us-central1-c \
--num-nodes 2

Output:

NAME          LOCATION       MASTER_VERSION   MASTER_IP      MACHINE_TYPE  NODE_VERSION     NUM_NODES  STATUS
k8s-concepts  us-central1-c  1.19.9-gke.1400  34.121.222.83  e2-medium     1.19.9-gke.1400  2          RUNNING

Step 3 Authenticate to the cluster.

gcloud container clusters get-credentials k8s-concepts --zone us-central1-c

2.2 Setup KUBECTL AUTOCOMPLETE¶

Since we going to use a lot of kubectl cli let's setup autocomplete.

source <(kubectl completion bash)
echo "source <(kubectl completion bash)" >> ~/.bashrc

2.3 Create 'dev' namespace and make it default.¶

Step 1 Create 'dev' namespace that's going to be used to develop and deploy Notestaker application on Kubernetes using kubetl CLI.

kubectl create ns dev

Step 2 Use dev context to create K8s resources inside this namespace.

kubectl config set-context --current --namespace=dev

Step 3 Verify current context:

kubectl config view | grep namespace

Result

dev

2.4 Create Service Object for MySQL¶

Step 1 Locate directory where kubernetes manifests going to be stored.

cd ~/ycit019/
git pull       # Pull latest assignement3

In case you don't have this folder clone it as following:

cd ~
git clone https://github.com/Cloud-Architects-Program/ycit019
cd ~/ycit019/Assignment3/
ls

Step 2 Go into the local repository you've created:

cd ~/$MY_REPO

Step 3 Copy Assignment 3 deploy folder to your repo:

git pull                              # Pull latest code from you repo
cp -r ~/ycit019/Assignment3/deploy .

Step 4 Commit deploy folder using the following Git commands:

git status 
git add .
git commit -m "adding K8s manifests in deploy folder"

Step 5 Once you've committed code to the local repository, add its contents to Cloud Source Repositories using the git push command:

git push origin master

Step 6 Define a Kubernetes Service object for the backend MySQL database.

cd ~/$MY_REPO/deploy

Follow instructions below to populate gowebapp-mysql-service.yaml

For reference, please see Service docs:

https://kubernetes.io/docs/concepts/services-networking/service/#defining-a-service

Additionally, you can use kubectl built-in docs for any type of resources:

kubectl explain service

vim gowebapp-mysql-service.yaml

Note

You can also use VCS or Cloud Code to work with yaml manifest.

apiVersion: v1
kind: Service
metadata:
  name: gowebapp-mysql
  labels:
    run: gowebapp-mysql
spec:
  clusterIP: None
  ports:
  - port: 3306
    targetPort: 3306
  selector:
    run: gowebapp-mysql

Step 3 Create a Service object for MySQL

kubectl apply -f gowebapp-mysql-service.yaml --record

Step 4 Check to make sure it worked

kubectl get service -l "run=gowebapp-mysql"

2.5 Create Deployment object for the backend MySQL database¶

Step 1 Follow instructions below to populate gowebapp-mysql-deployment.yaml

For reference, please see Deployment doc:

https://kubernetes.io/docs/concepts/workloads/controllers/deployment

vim gowebapp-mysql-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: gowebapp-mysql
  labels:
    run: gowebapp-mysql
    tier: backend
spec:
  replicas: 1
  selector:
    matchLabels:
      run: gowebapp-mysql
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        run: gowebapp-mysql
    spec:
      containers:
      - env:
        - name: MYSQL_ROOT_PASSWORD
          value: rootpasswd
        image: gcr.io/${PROJECT_ID}/gowebapp-mysql:v1
        name: gowebapp-mysql
        ports:
        - containerPort: 3306

Step 2 Create a Deployment object for MySQL

kubectl apply -f gowebapp-mysql-deployment.yaml --record

Step 3 Check to make sure it worked

kubectl get deployment -l "run=gowebapp-mysql"

Step 3 Check mysql pod logs:

List mysql Pods and note the name the pod:

kubectl get pods -l "run=gowebapp-mysql"

Ensure Mysql is up by looking at pod logs:

kubectl logs <Pod_name>

Result

We have created Service and Deployment for backend application.

2.5 Create a K8s Service for the frontend gowebapp.¶

Step 1 Follow instructions below to populate gowebapp-service.yaml

vim gowebapp-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: gowebapp
  labels:
    run: gowebapp
spec:
  ports:
  - port: 9000
    targetPort: 80
  selector:
    run: gowebapp
  type: LoadBalancer

Step 2 Create a Service object for gowebapp

kubectl apply -f gowebapp-service.yaml --record

Step 3 Check to make sure it worked

kubectl get service -l "run=gowebapp"

2.6 Create a K8s Deployment object for the frontend gowebapp¶

Step 1 Follow instructions below to populate gowebapp-deployment.yaml

vim gowebapp-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: gowebapp
  labels:
    run: gowebapp
spec:
  replicas: 2
  selector:
    matchLabels:
      run: gowebapp
  template:
    metadata:
      labels:
        run: gowebapp
    spec:
      containers:
      - env:
        - name: MYSQL_ROOT_PASSWORD
          value: rootpasswd
        image: gcr.io/${PROJECT_ID}/gowebapp:v1
        name: gowebapp
        ports:
        - containerPort: 80

Step 2 Create a Deployment object for gowebapp

kubectl apply -f gowebapp-deployment.yaml --record

Step 3 Check to make sure it worked

kubectl get deployment -l "run=gowebapp"

Step 4 Access your application on Public IP via automatically created Loadbalancer created for gowebapp service.

To get the value of Loadbalancer run following command:

kubectl get svc gowebapp -o wide

Expected output:

NAME             TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)          AGE
gowebapp         Loadbalancer 10.107.15.39  XXXXXX        9000:32634/TCP   30m
gowebapp-mysql   ClusterIP   None           <none>        3306/TCP         1h

Step 5 Access Loadbalancer IP via browser:

Result

Congrats!!! You've deployed you code to Kubernetes

2.7 Fix gowebapp code bugs and build a new image.¶

Task: As you've noticed gowebapp frontend app has YCIT019 logo in it. Since you may want to use application for you personal needs, let's change YCIT019 logo to you Name.

Step 1 Modify gowebapp frontend so that it has name of you company and link to company web page e.g.

vim ~/$MY_REPO/gowebapp/code/template/partial/footer.tmpl

Step 2 Build a new version of Image

cd ~/$MY_REPO/gowebapp
docker build -t gcr.io/${PROJECT_ID}/gowebapp:v2 .
docker push gcr.io/${PROJECT_ID}/gowebapp:v2 .

2.7 Rolling Upgrade¶

For gowebapp frontend deployment manifest we've not specified any upgrade strategy type. It means application will use default Upgrade strategy called RollingUpdate.

RollingUpdate strategy - updates Pods in a rolling update fashion.

maxUnavailable - is an optional field that specifies the maximum number of Pods that can be unavailable during the update process. By default, it ensures that at least 25% less than the desired number of Pods are up (25% max unavailable).

Max Surge - is an optional field that specifies the maximum number of Pods that can be created over the desired number of Pods. By default, it ensures that at most 25% more than the desired number of Pods are up (25% max surge).

Step 1 Locate directory with manifest

cd  ~/$MY_REPO/deploy

Step 2 Trigger rolling upgrade using kubectl set command

kubectl set image deployments/gowebapp gowebapp=gcr.io/${PROJECT_ID}/gowebapp:v2

Step 3 Verify rollout history

kubectl rollout history deployment/gowebapp

Step 4 Perform Rollback to v1

kubectl rollout undo deployment/gowebapp --to-revision=1

Step 1 Commit deploy folder using the following Git commands:

git add .
git commit -m "k8s manifests"

Step 2 Push commit to the Cloud Source Repositories:

git push origin master

2.9 Cleaning Up¶

Step 1 Delete the cluster

gcloud container clusters delete k8s-concepts

1 Deploy Applications on Kubernetes¶

1.1 Development Tools¶

2.1 Create GKE Cluster¶

2.2 Setup KUBECTL AUTOCOMPLETE¶

2.3 Create 'dev' namespace and make it default.¶

2.4 Create Service Object for MySQL¶

2.5 Create Deployment object for the backend MySQL database¶

2.5 Create a K8s Service for the frontend gowebapp.¶

2.6 Create a K8s Deployment object for the frontend gowebapp¶

2.7 Fix gowebapp code bugs and build a new image.¶

2.7 Rolling Upgrade¶

2.8 Commit K8s manifests to repository and share it with Instructor/Teacher¶

2.9 Cleaning Up¶