• Docker Images are hosted in dockerhub

• When code is changed, circleci builds docker images, runs tests, and starts microservices

• create_eks.sh creates a kubernetes cluser in AWS.

Rolling Updates:

• Rolling updates can be made by running kubectl apply -f {deployment yml file}, for example: udacity-c3-deployment/k8s/frontend-deployment.yaml

• Rolling update is also defined in udacity-c3-deployment/k8s/frontend-deployment.yaml.

spec: replicas: 2 strategy: type: RollingUpdate rollingUpdate: maxSurge: 1 maxUnavailable: 0

• To perform rolling update, change the version in deployment to a newer version, like v3m or change the container image.

• To perfrom a rollout, following command was issued, and the site got restored to the previous version. kubectl rollout undo deployment/{DEPLOYMENT NAME}

kubernetes Cluster

• Kubernetes cluster is created by cloudformation template on Amazon. The files needed for cluster creation is in cloudformation folder.

To build kubernetes deployment, and service in AWS, run:

• kubectl create -f frontend-deployment.yaml
• output deployment.extensions/frontend created
• kubectl create -f frontend-service.yaml
• output service/frontend created
• kubectl create -f backend-user-deployment.yaml
• output deployment.extensions/backend-user created
• kubectl create -f backend-user-service.yaml
• output service/backend-user created
• kubectl create -f backend-feed-deployment.yaml
• output deployment.extensions/backend-feed created
• kubectl create -f backend-feed-service.yaml
• output service/backend-feed created
• kubectl create -f reverseproxy-deployment.yaml
• output deployment.extensions/reverseproxy created
• kubectl create -f reverseproxy-service.yaml
• output service/reverseproxy created

How to update the site?

Push changes to git, it will trigger a build pipeline that runs tests, and lints the source codes. If build passes, docker image is uploaded, and a udagram site is build. When the build step passes, kubernetes can be run on the clusters created by ./create_eks.sh command.

• Cloudwatch Logs are created in the EKS clusster AWS concole. Log details are shown in the screenshots of this project in the screenshot directory

A/B Deployment

• A/B tests are performed by deplying different versions of the site at the same time.

• New Docker image is created

• New deployemnt yml file is created in the deployment/k8s folder called frontend-canary-deployment.yml

• Replica set is scaled down to 1

• The app: frontend, and track: stable are added/changed so that the newer vewrsion has a label

• Finally, following command is run `kubectl apply -f frontend-canary-deployment.yml'