Startup Local Kubernetes via Minikube

2019 iT 邦幫忙鐵人賽

DAY 3

Kubernetes

KK8s系列第 3 篇

2019鐵人賽 kubernetes

小夫

2018-10-18 00:11:11

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透過Minikube 創建本機 K8s環境

我先於自己Ubuntu電腦中，進行安裝 Minikube & Kubectl，去產生一個 K8s簡易環境。
安裝步驟記錄如下：

要使用Minikube，則主機上需具備Hypervisor環境，例如VirtualBox～

安裝參考頁：
https://kubernetes.io/docs/tasks/tools/install-minikube/
https://github.com/kubernetes/minikube/releases
https://kubernetes.io/docs/tasks/tools/install-kubectl/#install-kubectl-binary-using-curl

# 下載 minikube
[user@minikube ~]$ curl -Lo minikube https://storage.googleapis.com/minikube/releases/v0.30.0/minikube-linux-amd64 && chmod +x minikube && sudo cp minikube /usr/local/bin/ && rm minikube
minikube version
minikube version: v0.30.0
# 下載 kubectl
curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl
chmod +x ./kubectl
sudo mv ./kubectl /usr/local/bin/kubectl

[user@minikube ~]$ kubectl version
Client Version: version.Info{Major:"1", Minor:"12", GitVersion:"v1.12.1", GitCommit:"4ed3216f3ec431b140b1d899130a69fc671678f4", GitTreeState:"clean", BuildDate:"2018-10-05T16:46:06Z", GoVersion:"go1.10.4", Compiler:"gc", Platform:"linux/amd64"}
The connection to the server localhost:8080 was refused - did you specify the right host or port?

# 如僅安裝 minikube，執行時會提醒需安裝 kubectl。
[user@minikube ~]$ minikube status
========================================
kubectl could not be found on your path. kubectl is a requirement for using minikube
To install kubectl, please run the following:

curl -Lo kubectl https://storage.googleapis.com/kubernetes-release/release/v1.10.0/bin/linux/amd64/kubectl && chmod +x kubectl && sudo cp kubectl /usr/local/bin/ && rm kubectl

To disable this message, run the following:

minikube config set WantKubectlDownloadMsg false
========================================
minikube:
cluster:
kubectl:
[user@minikube ~]$

啟動 K8s環境

[user@minikube ~]$ minikube start
Starting local Kubernetes v1.10.0 cluster...
Starting VM...
Downloading Minikube ISO
 170.78 MB / 170.78 MB [============================================] 100.00% 0s
 171.Getting VM IP address...
Moving files into cluster...
Downloading kubeadm v1.10.0
Downloading kubelet v1.10.0
Finished Downloading kubelet v1.10.0
Finished Downloading kubeadm v1.10.0
Setting up certs...
Connecting to cluster...
Setting up kubeconfig...
Starting cluster components...
Kubectl is now configured to use the cluster.
Loading cached images from config file.

觀察 K8s狀態

# Status
[user@minikube ~]$ minikube status
minikube: Running
cluster: Running
kubectl: Correctly Configured: pointing to minikube-vm at 192.168.99.100
[user@minikube ~]$

# Cluster Version
[user@minikube ~]$ kubectl version
Client Version: version.Info{Major:"1", Minor:"12", GitVersion:"v1.12.1", GitCommit:"4ed3216f3ec431b140b1d899130a69fc671678f4", GitTreeState:"clean", BuildDate:"2018-10-05T16:46:06Z", GoVersion:"go1.10.4", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.0", GitCommit:"fc32d2f3698e36b93322a3465f63a14e9f0eaead", GitTreeState:"clean", BuildDate:"2018-03-26T16:44:10Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"linux/amd64"}

在 kubectl version 資訊中看到兩個狀態：Client 指的是 Kubectl 執行檔本身、Server 指的是 K8s API 伺服器。

# Component Status
[user@minikube ~]$ kubectl get componentstatuses
NAME                 STATUS    MESSAGE              ERROR
controller-manager   Healthy   ok
scheduler            Healthy   ok
etcd-0               Healthy   {"health": "true"}

# K8s node
[user@minikube ~]$ kubectl get node
NAME       STATUS   ROLES    AGE   VERSION
minikube   Ready    master   3h    v1.10.0
[user@minikube ~]$

部署第一個 service / pod

部署參考頁：https://kubernetes.io/docs/setup/minikube/#installation

# 部署
[user@minikube ~]$ kubectl run hello-minikube --image=k8s.gcr.io/echoserver:1.10 --port=8080
kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead.
deployment.apps/hello-minikube created
[user@minikube ~]$

[user@minikube ~]$ kubectl get pod
NAME                              READY   STATUS    RESTARTS   AGE
hello-minikube-7c77b68cff-l7smf   1/1     Running   0          26s

# Expose it as a new Kubernetes Service
[user@minikube ~]$ kubectl expose deployment hello-minikube --type=NodePort
service/hello-minikube exposed

[user@minikube ~]$ kubectl get service
NAME             TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
hello-minikube   NodePort    10.97.245.120   <none>        8080:31944/TCP   9s
kubernetes       ClusterIP   10.96.0.1       <none>        443/TCP          4h
[user@minikube ~]$

測試 Service運行狀況

[user@minikube ~]$ curl $(minikube service hello-minikube --url)
Hostname: hello-minikube-7c77b68cff-l7smf

Pod Information:
        -no pod information available-

Server values:
        server_version=nginx: 1.13.3 - lua: 10008

Request Information:
        client_address=172.17.0.1
        method=GET
        real path=/
        query=
        request_version=1.1
        request_scheme=http
        request_uri=http://192.168.99.100:8080/

Request Headers:
        accept=*/*
        host=192.168.99.100:31944
        user-agent=curl/7.47.0

Request Body:
        -no body in request-
        

[user@minikube ~]$

刪除 Service / Pod

# Delete Services
[user@minikube ~]$ kubectl delete services hello-minikube
service "hello-minikube" deleted
# View Service \ Pod
[user@minikube ~]$ kubectl get service
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   4h

[user@minikube ~]$ kubectl get pod
NAME                              READY   STATUS    RESTARTS   AGE
hello-minikube-7c77b68cff-l7smf   1/1     Running   0          20m

# Delete Pod
[user@minikube ~]$ kubectl delete deployment hello-minikube
deployment.extensions "hello-minikube" deleted
# View Pod
[user@minikube ~]$ kubectl get pod
NAME                              READY   STATUS        RESTARTS   AGE
hello-minikube-7c77b68cff-l7smf   1/1     Terminating   0          20m
#
[user@minikube ~]$ kubectl get pod
No resources found.

停止本機 K8s環境

[user@minikube ~]$ minikube stop
Stopping local Kubernetes cluster...
Machine stopped.

[user@minikube ~]$ minikube status
minikube: Stopped
cluster:
kubectl:

此篇，主要先自我練習本機 K8s環境從無到建立，然後再啟動第一個pod / service等所做的步驟記錄，下一篇再予以介紹上述牽涉到的觀念。
感謝看官 :)