# 練習kubernetes的安裝與測試

## 建立kubeadm
<p>
參考<br>
https://ithelp.ithome.com.tw/articles/10235069<br>
&&<br>
https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/
</p>

## 前置

<p>
準備兩台虛擬機，都是VMWare Ubuntu20.04，分別用來配置Control Plane、Node，至少2core、4G記憶體
</p>

## Control Plane & Node上皆須執行

### step1.更新 repositpories
<code>$ sudo su</code>
<code>$ apt-get update</code>

### step2.關閉 swap space
<code>$ swapoff -a</code>
<code>$ vim /etc/fstab</code>
將 /swapfile 這一行註解起來(前方加上 '#' )

### step3.修改 hostname

<code>$ vim /etc/hostname</code>
<code>k8master</code>
<p>刪掉原本名稱，任取一個新的<br>
EX:將ubuntu改為k8master，而Node改為k8worker<br>
重啟虛擬機，<code>hostname</code>即成功修改
</p>

### step4.設定DNS - 修改 host file

<code>$ vim /etc/hosts</code>
<p>加入:</p>

<code>192.168.132.241 k8master</code>
<code>192.168.132.173 k8worker</code>

<p>原本的資料不需更改，只要新增就好</p>


### step5.安裝 ssh

<code>$ apt-get install openssh-server</code>

### step6.安裝 Docker

<code>$ apt-get update</code>
<code>$ apt-get install -y docker.io</code>

### step7.建立 kubernetes 環境

<p>
由於需更新apt package，網路找到的教學文常常出現報錯:找不到資源包連結<br>
因此我去k8s的官方網站:<br>https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/install-kubeadm/<br>
</p>


<div id="k8s-install-0" class="tab-pane show active" role="tabpanel" aria-labelledby="k8s-install-0">

<p></p><ol>
<li>
<p>Update the <code>apt</code> package index and install packages needed to use the Kubernetes <code>apt</code> repository:</p>
<div class="highlight"><pre style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4"><code class="language-shell" data-lang="shell">sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl
</code></pre></div></li>
<li>
<p>Download the Google Cloud public signing key:</p>
<div class="highlight"><pre style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4"><code class="language-shell" data-lang="shell">sudo curl -fsSLo /usr/share/keyrings/kubernetes-archive-keyring.gpg https://packages.cloud.google.com/apt/doc/apt-key.gpg
</code></pre></div></li>
<li>
<p>Add the Kubernetes <code>apt</code> repository:</p>
<div class="highlight"><pre style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4"><code class="language-shell" data-lang="shell"><span style="color:#a2f">echo</span> <span style="color:#b44">"deb [signed-by=/usr/share/keyrings/kubernetes-archive-keyring.gpg] https://apt.kubernetes.io/ kubernetes-xenial main"</span> | sudo tee /etc/apt/sources.list.d/kubernetes.list
</code></pre></div></li>
<li>
<p>Update <code>apt</code> package index, install kubelet, kubeadm and kubectl, and pin their version:</p>
<div class="highlight"><pre style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4"><code class="language-shell" data-lang="shell">sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubectl
sudo apt-mark hold kubelet kubeadm kubectl
</code></pre></div></li>
</ol>
</div>

## 只在Control Plane上執行

### 初始化Control Plane
<code>$ sudo kubeadm init --pod-network-cidr=10.244.0.0/16</code>


<p>
依序輸入系統給的三個指令:
</p>

<pre><code class="language-bash= hljs">$ mkdir -p <span class="hljs-variable">$HOME</span>/.kube
$ sudo cp -i /etc/kubernetes/admin.conf <span class="hljs-variable">$HOME</span>/.kube/config
$ sudo chown $(id -u):$(id -g) <span class="hljs-variable">$HOME</span>/.kube/config
</code></pre>

<p>
將最後兩行指令存起來，之後k8worker要加入此集群，執行此指令即可
</p>

<pre><code class="language-= hljs css"><span class="hljs-selector-tag">kubeadm</span> <span class="hljs-selector-tag">join</span> 192<span class="hljs-selector-class">.168</span><span class="hljs-selector-class">.216</span><span class="hljs-selector-class">.131</span><span class="hljs-selector-pseudo">:6443</span> <span class="hljs-selector-tag">--token</span> <span class="hljs-selector-tag">ra7nvg</span><span class="hljs-selector-class">.wkigjihyc4sy8xh3</span> \
<span class="hljs-selector-tag">--discovery-token-ca-cert-hash</span> <span class="hljs-selector-tag">sha256</span><span class="hljs-selector-pseudo">:323d12aaf45950ff6c453b6c54ffb158957269a0177f47006ec08d1b75df4228</span>
</code></pre>

## 只在Node上執行

### kubeadm join

<p>
輸入剛剛得到的<code>$ kubeadm join 192.168.216.131:6443 --token</code>....
</p>


<p>
在Control Plane輸入指令<code>$ kubectl get nodes</code>
</p>


<p>
看到k8worker已被加入，不過可以看到<code>STATUS</code>都是<code>NotReady</code>，因為還沒安裝<code>CNI</code>
</p>

## 安裝CNI (Network Plugin)

<p>
在Control Plane輸入指令<br>
<pre><code class="language-= hljs css">$ kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"</code></pre>
</p>


<p>
<code>$ kubectl get nodes</code>查看<code>STATUS</code>
</p>


<p>
<code>$ kubectl label node k8worker node-role.kubernetes.io/worker=worker</code><br>
可為k8worker的<code>ROLES</code>命名，範例命名為<code>worker</code>
</p>