[雲端] K8s / Ingress === ###### tags: `雲端 / K8s` ###### tags: `雲端`, `K8s`, `ingress` <br> ![](https://i.imgur.com/vsCp0RX.png)<br><br> [TOC] <br> ## [Kubernetes 基礎教學（二）實作範例：Pod、Service、Deployment、Ingress](https://medium.com/@C.W.Hu/kubernetes-implement-ingress-deployment-tutorial-7431c5f96c3e) ![](https://i.imgur.com/EgVch8A.png) ### deploy-demo.yam ```yaml= apiVersion: apps/v1 kind: Deployment metadata: name: a-kuard spec: template: metadata: name: kuard-pod labels: app: kuard spec: containers: - name: kuard-container image: gcr.io/kuar-demo/kuard-amd64:1 ports: - containerPort: 8080 selector: matchLabels: app: kuard replicas: 3 --- apiVersion: apps/v1 kind: Deployment metadata: name: b-nginx spec: template: metadata: name: nginx-pod labels: app: nginx spec: containers: - name: nginx-container image: nginx ports: - containerPort: 8080 selector: matchLabels: app: nginx replicas: 3 ``` - 若 replicas 太多，可事後透過 kubectl scale 指令調整 ```k8s kubectl scale deployment a-kuard --replicas=2 ``` - 查看現有的 pods ``` > kubectl get pods NAME READY STATUS RESTARTS AGE b-nginx-69cfb869c4-x2pt6 1/1 Running 0 44h b-nginx-69cfb869c4-n5qf5 1/1 Running 0 44h b-nginx-69cfb869c4-4557m 1/1 Running 0 4h57m a-kuard-7947d7769f-6wcx6 1/1 Running 0 44h a-kuard-7947d7769f-k9tgh 1/1 Running 0 44h ``` - 建立 service 來存取 pod 時，service 會隨機存取 pod，猶如 load balance <br> ### service-demo.yam ```yaml= apiVersion: v1 kind: Service metadata: name: a-kuard-service spec: selector: app: kuard type: NodePort ports: - name: 80-to-8080-kuard port: 80 targetPort: 8080 --- apiVersion: v1 kind: Service metadata: name: b-nginx-service spec: selector: app: nginx type: NodePort ports: - name: 80-to-80-nginx port: 80 targetPort: 80 ``` - Rancher 上的示意圖 [![](https://i.imgur.com/uiU8cc9.png)](https://i.imgur.com/uiU8cc9.png) - 在叢集內，開放 pod 的存取 - a-kuard-service (Cluster IP: 10.43.47.68, port:80) 對到 kuard pod (port:8080) - b-nginx-service (Cluster IP: 10.43.5.36, port:80) 對到 nginx pod (port:80) - 在叢集外，開放 service 的存取 - 沒指定 nodePort，nodePort 會隨機配置 - externalIP:nodePort1 對到 a-kuard-service (Cluster IP: 10.43.47.68, port:80) <img src="https://i.imgur.com/qj7mm3r.png" style="border: 1px solid"/> <br> - externalIP:nodePort2 對到 b-nginx-service (Cluster IP: 10.43.5.36, port:80) <img src="https://i.imgur.com/uUeI3cF.png" style="border: 1px solid"/> <br> ### ingress-demo.yam (v1) ```yaml= apiVersion: networking.k8s.io/v1beta1 kind: Ingress metadata: name: load-balance-service spec: rules: - host: a-kuard.com http: paths: - backend: serviceName: a-kuard-service servicePort: 80 - host: b-nginx.com http: paths: - backend: serviceName: b-nginx-service servicePort: 80 ``` - Rancher 上的示意圖 ![](https://i.imgur.com/kcgzarP.png) - serviceName 是綁訂目前已有的 service 的 name - servicePort 是對外開放的 port (供瀏覽器存取)，不是 a-kuard-service 的 port - 輸入 **```a-kuard.com:80```** (詳見底下 DNS 設定) 會轉到 a-kuard-service - 輸入 **```b-nginx.com:80```** (詳見底下 DNS 設定) 會轉到 b-nginx-service - 直接輸入 **```192.168.56.87```** ，無法轉到任何 service， 會顯示```404 page not found``` - 它台電腦的瀏覽器，若想要瀏覽 a-kuard.com, b-nginx.com 需要在 /etc/hosts 添加 ``` $ nano /etc/hosts ... 192.168.56.87 a-kuard.com 192.168.56.87 b-nginx.com ``` <img src="https://i.imgur.com/1IMdjf9.png" style="border: 1px solid"/> <br> <br> <img src="https://i.imgur.com/fcKA0UZ.png" style="border: 1px solid"/> ### ingress-demo.yam (v2) ```yaml= apiVersion: networking.k8s.io/v1beta1 kind: Ingress metadata: name: load-balance-service spec: rules: - host: a-kuard.com http: paths: - backend: serviceName: a-kuard-service servicePort: 80 - host: b-nginx.com http: paths: - backend: serviceName: b-nginx-service servicePort: 80 # the default backend backend: serviceName: a-kuard-service servicePort: 80 ``` - 第 21~23 行，可以設置預設的 backend - Rancher 上的示意圖 ![](https://i.imgur.com/zgSXQhw.png) - 直接輸入 **```192.168.56.87```** ，可以轉到 a-kuard-service <img src="https://i.imgur.com/CklzMn6.png" style="border: 1px solid"/> <br> ## apiVersion > Ingress apiVersion 參數值不同，格式欄位也可能不同 - 例如： ``` v1beta: <-- 常見的範本 backend: - serviceName: xxx - servicePort: yyy --- v1： backend: - service - name: xxx - port: number: yyy ``` - 參考資料 - [Expecting apiVersion - networking.k8s.io/v1 instead of extensions/v1beta1](https://github.com/kubernetes/kubernetes/issues/94761) <br> ## Debug - 基本範例 ```yaml apiVersion: extensions/v1beta1 kind: Ingress metadata: name: {{ include "tj-helm-whale-ingress-demo2.name" . }} annotations: nginx.ingress.kubernetes.io/rewrite-target: / spec: rules: - http: paths: - path: {{ .Values.ingress.path }} backend: serviceName: {{ .Values.ingress.serviceName }} servicePort: {{ .Values.ingress.servicePort }} ``` - ```nginx.ingress.kubernetes.io/rewrite-target: /``` 參數是必要的 - 查看 ingress name ``` $ ku get ing Warning: extensions/v1beta1 Ingress is deprecated in v1.14+, unavailable in v1.22+; use networking.k8s.io/v1 Ingress NAME CLASS HOSTS ADDRESS PORTS AGE tj-helm-whale-ingress-demo2 <none> * 10.98.112.86 80 4m32s ``` - ingress name 為 ```tj-helm-whale-ingress-demo2``` - 查看 tj-helm-whale-ingress-demo2 細節 ``` $ ku describe ing tj-helm-whale-ingress-demo2 Warning: extensions/v1beta1 Ingress is deprecated in v1.14+, unavailable in v1.22+; use networking.k8s.io/v1 Ingress Name: tj-helm-whale-ingress-demo2 Namespace: default Address: 10.98.112.86 Default backend: default-http-backend:80 (<error: endpoints "default-http-backend" not found>) Rules: Host Path Backends ---- ---- -------- * /blue tjdemo3-tj-helm-whale-ingress-demo2:80 (10.244.0.34:3000,10.244.1.80:3000) Annotations: meta.helm.sh/release-name: tjdemo3 meta.helm.sh/release-namespace: default nginx.ingress.kubernetes.io/rewrite-target: / Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal CREATE 4m36s nginx-ingress-controller Ingress default/tj-helm-whale-ingress-demo2 Normal UPDATE 4m26s nginx-ingress-controller Ingress default/tj-helm-whale-ingress-demo2 ``` - address 為 ```10.98.112.86``` - path 為 ```/blue``` - :warning: **注意** - Backends 欄位的 service name 有沒有對應到你要的 service - Helm3 建立出來的 service name 好像對不起來？以至於無法存取... - 進行測試 ``` $ curl 10.98.112.86/blue ``` - 查看對外的 ingress service ```bash $ ku get svc -o wide -n ingress-nginx NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR ingress-nginx NodePort 10.98.112.86 <none> 80:30511/TCP,443:30152/TCP 4d2h app.kubernetes.io/name=ingress-nginx,app.kubernetes.io/part-of=ingress-nginx ``` ``` $ ku describe svc ingress-nginx -n ingress-nginx Name: ingress-nginx Namespace: ingress-nginx Labels: app.kubernetes.io/name=ingress-nginx app.kubernetes.io/part-of=ingress-nginx Annotations: <none> Selector: app.kubernetes.io/name=ingress-nginx,app.kubernetes.io/part-of=ingress-nginx Type: NodePort IP: 10.98.112.86 Port: http 80/TCP TargetPort: 80/TCP NodePort: http 30511/TCP Endpoints: 10.244.1.19:80 Port: https 443/TCP TargetPort: 443/TCP NodePort: https 30152/TCP Endpoints: 10.244.1.19:443 Session Affinity: None External Traffic Policy: Cluster Events: <none> ``` - 進行測試 ``` $ curl 127.0.0.1:30511/blue ``` http://203.145.218.3:30511/blue ![](https://i.imgur.com/kyJwhIu.png) <br> ## 參考資料 - [[K8s官方] Ingress](https://kubernetes.io/docs/concepts/services-networking/ingress/) - Kubernetes 基礎教學 - [Kubernetes 基礎教學（一）原理介紹](https://medium.com/@C.W.Hu/kubernetes-basic-concept-tutorial-e033e3504ec0) - worker node - kubelet - 角色 - worker node 上的管理員 - 職責 - 負責管理該 node 上的 pod 的狀態 - 負責與 master node 溝通 - kube-proxy - 角色 - worker node 上的傳訊員 - 職責 - 負責更新該 node 上的 iptables (負責啟用 k8s 服務的網路規則) - 負責網路連線的轉發 - container runtime - 角色 - worker node 上的容器執行者 - k8s: docker engine - k3s: containerd (containerd is based on the Docker Engine's core container runtime) - 職責 - 負責該 node 上的容器執行 - master node - k8s 的指揮中心 - controller-manager - k8s 裡一個個負責監視 cluster 狀態的程序 - Node Controller - Replication Controller - [Kubernetes 基礎教學（二）實作範例：Pod、Service、Deployment、Ingress](https://medium.com/@C.W.Hu/kubernetes-implement-ingress-deployment-tutorial-7431c5f96c3e) :+1: :100: - [Kubernetes 基礎教學（三）Helm 介紹與建立 Chart](https://medium.com/@C.W.Hu/kubernetes-helm-chart-tutorial-fbdad62a8b61) - [[官網] 一个最小的 Ingress 资源示例：](https://kubernetes.io/zh/docs/concepts/services-networking/ingress/) ![](https://i.imgur.com/2rrKY9p.png) <br> ## 待消化資料 - [How To Set Up an Nginx Ingress on DigitalOcean Kubernetes Using Helm](https://www.digitalocean.com/community/tutorials/how-to-set-up-an-nginx-ingress-on-digitalocean-kubernetes-using-helm)