Play with Kubernetes
這個世間就是這麼漂亮，都有此 PWK 工具網站可以練習 K8s
此網站工具僅需具備 github or Docker 帳號即可登入使用～
登入後，先點選左邊畫面 + ADD NEW INSTANCE，新增節點
初始化
新增後，Terminal 中就有初始化說明
1. Initializes cluster master node:
kubeadm init --apiserver-advertise-address $(hostname -i)
2. Initialize cluster networking:
kubectl apply -n kube-system -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 |tr -d '\n')"
3. (Optional) Create an nginx deployment:
kubectl apply -f https://raw.githubusercontent.com/kubernetes/website/master/content/en/examples/application/nginx-app.yaml
The PWK team.
Node join
開始進行基本初始化步驟 1
1. Initializes cluster master node:
kubeadm init --apiserver-advertise-address $(hostname -i)
........<忽略>........
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
Your Kubernetes master has initialized successfully!
完成 Master node 初始化節點之後，進行步驟 2
# 2. Initialize cluster networking:
[node1 ~]$ kubectl apply -n kube-system -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 |tr -d '\n')"
serviceaccount/weave-net created
clusterrole.rbac.authorization.k8s.io/weave-net created
clusterrolebinding.rbac.authorization.k8s.io/weave-net created
role.rbac.authorization.k8s.io/weave-net created
rolebinding.rbac.authorization.k8s.io/weave-net created
daemonset.extensions/weave-net created
[node1 ~]$
當完成上面步驟 1.Initializes cluster master node之後，此 instance 即成為 Master node
步驟完成後，會提供kubectl join指令（如下）
kubeadm join 192.168.0.13:6443 --token 6bcc6s.zkvi8hv0hhpxkd1v --discovery-token-ca-cert-hash sha256:9ceb947c39b2a4e10396d846dfda4cba9d27958ee687eb9b406cff0400f27223
此時於左邊環境繼續 + ADD NEW INSTANCE，例如新增三個 K8s node
透過kubectl join指令將三個新 instance join 到第一台 instance 成為 work-nodes。
新增後，在 Master node 上，查看資訊：
[node1 ~]$ kubectl get node
NAME STATUS ROLES AGE VERSION
node1 Ready master 4m v1.11.3
node2 Ready <none> 2m v1.11.3
node3 Ready <none> 1m v1.11.3
node4 Ready <none> 58s v1.11.3
[node1 ~]$
部署範例 Nginx
當進行 Create an nginx deployment 時，就會依據此 nginx-app.yaml 進行創建 deployment、service、endpoint、pod 等角色物件。
[node1 ~]$ kubectl apply -f https://raw.githubusercontent.com/kubernetes/website/master/content/en/examples/application/nginx-app.yaml
service/my-nginx-svc created
deployment.apps/my-nginx created
[node1 ~]$
# 創建 services、pod 初期 pending 狀態
[node1 ~]$ kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 8m
my-nginx-svc LoadBalancer 10.107.145.35 <pending> 80:30997/TCP 28s
[node1 ~]$ kubectl get pods
NAME READY STATUS RESTARTS AGE
my-nginx-67594d6bf6-f94cb 0/1 ContainerCreating 0 42s
my-nginx-67594d6bf6-tfpg5 0/1 ContainerCreating 0 42s
my-nginx-67594d6bf6-trps7 0/1 ContainerCreating 0 42s
# 完成創建 pod 後狀態：Running
[node1 ~]$ kubectl get pods
NAME READY STATUS RESTARTS AGE
my-nginx-67594d6bf6-f94cb 1/1 Running 0 1m
my-nginx-67594d6bf6-tfpg5 1/1 Running 0 1m
my-nginx-67594d6bf6-trps7 1/1 Running 0 1m
完成部署此服務時，透過 kubectl 取得各物件資訊
# deployments
[node1 ~]$ kubectl get deployments
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
my-nginx 3 3 3 3 1m
# services
[node1 ~]$ kubectl get services
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 9m
my-nginx-svc LoadBalancer 10.107.145.35 <pending> 80:30997/TCP 1m
[node1 ~]$
# endpoints
[node1 ~]$ kubectl get endpoints -o wide
NAME ENDPOINTS AGE
kubernetes 192.168.0.13:6443 19m
my-nginx-svc 10.32.0.2:80,10.40.0.2:80,10.44.0.2:80 10m
[node1 ~]$
# pods
[node1 ~]$
[node1 ~]$ kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
my-nginx-67594d6bf6-f94cb 1/1 Running 0 10m 10.44.0.2 node3 <none>
my-nginx-67594d6bf6-tfpg5 1/1 Running 0 10m 10.40.0.2 node2 <none>
my-nginx-67594d6bf6-trps7 1/1 Running 0 10m 10.32.0.2 node4 <none>
完成部署後，在 “Play with Kubernetes” 介面上有個隨機性數字 30997 藍色連結
ps. 此藍色數字，是依據 Services 所隨機配置的外部 PORT。
點選連結後，即可看見 Nginx 服務的歡迎畫面。
