hello-rails-on-k8s

k8s の勉強

Rails を k8s 環境で動かす

helm

https://github.com/helm/helm

Hands on

0. Preparation

ローカルだと Ingress で Service を公開することはできない
クラスタ外からの HTTP リクエストを Service にルーティングするために nginx_ingress_controller をデプロイしておく

$ kubectl -f apply https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.16.2/deploy/mandatory.yaml
$ kubectl -f apply https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.16.2/deploy/provider/cloud-generic.yaml

Check deployed services and pods

$ kubectl get svc,pod --namespace ingress-nginx
NAME                           TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)                      AGE
service/default-http-backend   ClusterIP      10.110.86.111    <none>        80/TCP                       1d
service/ingress-nginx          LoadBalancer   10.105.208.212   localhost     80:32414/TCP,443:31696/TCP   1d

NAME                                            READY   STATUS    RESTARTS   AGE
pod/default-http-backend-7fb86fb47d-6th9z       1/1     Running   1          1d
pod/nginx-ingress-controller-78bd49949c-5vh5r   1/1     Running   0          1d

1. Build containers

$ docker build -f .docker/containers/app/Dockerfile   -t hello-rails-on-k8s-app:latest .
$ docker build -f .docker/containers/nginx/Dockerfile -t hello-rails-on-k8s-nginx:latest .
$ docker build -f .docker/containers/db/Dockerfile    -t hello-rails-on-k8s-db:latest .

2. Deploy by kubectl

Deploy

For application

$ kubectl apply -f .docker/kubernetes/webserver.yml
$ kubectl apply -f .docker/kubernetes/dbserver.yml
$ kubectl apply -f .docker/kubernetes/ingress.yml

For logging

$ kubectl apply -f .docker/kubernetes/fluentd.yml
$ kubectl apply -f .docker/kubernetes/elasticsearch.yml
$ kubectl apply -f .docker/kubernetes/kibana.yml

Check

Request to rails

curl http://localhost -H "Host: hello-rails-on-k8s.local"

Access to Kibana
http://localhost:30050

Note:
curl http://localhost -H "Host: hello-rails-on-k8s.local" は、
http://localhost に対してリクエストするんだけど、あたかも http://hello-rails-on-k8s.local としてリクエストしたように見せかけられる
ref: curlをhost指定して実行する - するめとめがね

Delete objects

$ kubectl delete -f .docker/kubernetes/webserver.yml
$ kubectl delete -f .docker/kubernetes/dbserver.yml
$ kubectl delete -f .docker/kubernetes/fluentd.yml
$ kubectl delete -f .docker/kubernetes/elasticsearch.yml
$ kubectl delete -f .docker/kubernetes/kibana.yml
$ kubectl delete -f .docker/kubernetes/ingress.yml

3. Deploy by helm

Deploy

$ helm install --name hello-rails-on-k8s .helm/stable/hello-rails-on-k8s/

Check

Request to rails

$ curl http://localhost -H "Host: hello-rails-on-k8s.local"

Delete objects

$ helm delete hello-rails-on-k8s
# and purge
$ helm del --purge hello-rails-on-k8s