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Birthday-server

Google Container Engine based app

LICENSE Build Status

The application

  • It's a web application to wish happy birthday or how many days left to your birthday
  • Takes inputs from the URL query form and return the result or error message in JSON format
  • Please seed the test data in tests directory.
  • in the Makefile there's a rudimentary example of spawning all of the service and connecting them, plus sending a test request

Environment

  • the Go compiler is installed and the go command is on the path

  • make and anything else needed by the Makefile is installed and is on the path

  • docker is on the path and the user running make is in the docker group

  • a gcloud login was already performed so docker push just works

  • kubectl is on the path

  • a Kubernetes cluster is set up and the the default kubectl context points to that cluster. We can create the cluster using below commands

    gcloud config set project my-project-id
gcloud config set compute/zone us-central1-f
gcloud container clusters create example --zone us-central1-a \
 --num-nodes 2 --enable-autoscaling --min-nodes 1 --max-nodes 3 \
 --node-locations us-central1-a,us-central1-b,us-central1-f
gcloud container clusters get-credentials --cluster example

Building the Docker Image

  • Do a git init in the code and set respective user and email address
git config --global user.email "[EMAIL_ADDRESS]"
git config --global user.name "[USERNAME]"
  • Make initial commits to the source code repository
  • Create a repository to host your code
 gcloud source repos create sample-app
 git config credential.helper gcloud.sh
  • Add your newly created repository as remote
export PROJECT=$(gcloud info --format='value(config.project)')
git remote add origin https://source.developers.google.com/p/$PROJECT/r/example
  • Push your code to the new repository's master branch
git push origin master
  • Create a Tag for the code and push
git tag v1.0.0
git push --tags

Configuring the build triggers :

  • In GCP console click Build Triggers in the container registry seciotn
  • Select Cloud Source Repository and click Continue
  • Select example repository and select cloudbuild.yaml location: gcp/cloudbuild.yaml.
  • Select Trigger type as Tag and in the Tag regex provide v.*

Build and Test

  • Build images using make docker-images DOCKER_REPO=gcr.io/birthday-server
  • Create and test cluster using make kubernetes-test
  • Clean up after testing using make kubernetes-clean

Deployment

  • Do the necessary code changes , tag them and push to the repo. Once pushed we can check the auto build in the build history
  • We have three ways to do rolling update.

    • Using set image

      $ kubectl set image deployment <deployment> <container>=<image> --record
# example
git:mastkubectl set image deployment web-controller  web=example:v1.0.0 --record
deployment "web-controller" image updated

  • Modify the kubernetes manifest and update the docker image version.

    # format
$ kubectl replace -f <yaml> --record
# example
$ kubectl replace -f gcp/birthday-server.yml --record

  • Using Edit

    # format
$ kubectl edit deployment <deployment> --record
git:master *⚡ kubectl edit deployment web-controller --record

  • Check Status/Pause/Resume Deployments

    kubectl rollout status deployment web-controller # Check Status
kubectl rollout pause deployment web-controller # Pause Rolling Update
kubectl rollout resume deployment web-controller # Resume Rolling Update

  • To create and list the firewall rule that allows traffic into the cluster I use a gcloud compute command

gcloud compute firewall-rules create --allow=tcp:80 --target-tags=gke-example-default-pool-12d321682 example #creating the firewall rule
gcloud compute forwarding-rules list

Autoscaling

  • When you use kubectl autoscale, you specify a maximum and minimum number of replicas for your application, as well as a CPU utilization target.
  • For example, to set the maximum number of replicas to 4 and the minimum to 3, with a CPU utilization target of 50% utilization, run the following command:
git:master *⚡ kubectl  get deployments  # getting deployments list
NAME             DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
web-controller   2         2        2            2           1h

git:master *%=⚡ kubectl autoscale deployment web-controller --max 4 --min 3 --cpu-percent 50
deployment "web-controller" autoscaled

Rollback

to previous revision

 $ kubectl rollout undo deployment web-controller
 git:master *⚡ kubectl rollout undo deployment web-controller
 deployment "web-controller" rolled back

to specific revision

  $ kubectl rollout undo deployment web-controller --to-revision=<revision>
  # exmaple
  $ kubectl rollout undo deployment web-controller --to-revision=v1.0.1