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<time title="创建时间：2021-02-21 10:18:46 / 修改时间：10:20:47" itemprop="dateCreated datePublished" datetime="2021-02-21T10:18:46+08:00">2021-02-21</time>
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<p>hostport是一种把host的ip:port绑定到pod的port方法，是端口路由，访问host的ip:port即可访问pod的port。</p>
<p>hostport是一个三元组配置：<code><hostIP, hostPort, protocol></code> ，hostIP不配置时，默认为<code>0.0.0.0</code>，<code>protocol</code>默认为<code>TCP</code>。</p>
<p>如下的Pod声明文件，指nginx这个Pod使用hostport，使用的是<0.0.0.0, 80, TCP>，即host上所有IP的80端口的TCP连接，都会转发给该nginx Pod。</p>
<figure class="highlight yaml"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br></pre></td><td class="code"><pre><span class="line"><span class="attr">apiVersion:</span> <span class="string">v1</span></span><br><span class="line"><span class="attr">kind:</span> <span class="string">Pod</span></span><br><span class="line"><span class="attr">metadata:</span></span><br><span class="line"> <span class="attr">name:</span> <span class="string">nginx</span></span><br><span class="line"><span class="attr">spec:</span></span><br><span class="line"> <span class="attr">containers:</span></span><br><span class="line"> <span class="bullet">-</span> <span class="attr">image:</span> <span class="string">nginx</span></span><br><span class="line"> <span class="attr">name:</span> <span class="string">nginx</span></span><br><span class="line"> <span class="attr">ports:</span></span><br><span class="line"> <span class="bullet">-</span> <span class="attr">containerPort:</span> <span class="number">80</span></span><br><span class="line"> <span class="attr">hostPort:</span> <span class="number">80</span></span><br></pre></td></tr></table></figure>
<p>特点：</p>
<ol>
<li>host上的任何两个pod不能有相同的hostport。由于端口绑定，host上的某个端口只能被1个Pod所绑定。</li>
<li>host的ip和port资源是有限的，所能支持使用hostPort的pod数也是有限的。</li>
<li>灵活性差，需要维护name service。当pod被迁移到新node时，需要使用新node的ip访问pod。</li>
</ol>
<p>node1的ip为<code>10.0.13.3</code>，则：</p>
<ol>
<li><0.0.0.0, 80, TCP> 和 <10.0.13.3, 80, TCP>是冲突的。</li>
<li><10.0.13.3, TCP> 和 <10.0.13.3, 80, TCP>是冲突的。</li>
<li><0.0.0.0, 80, TCP> 和 <10.0.13.3, 80, UDP>是不冲突的。</li>
<li><10.0.13.3, 80, TCP> 和 <10.0.13.3, 80, UDP>是不冲突的。</li>
<li><0.0.0.0, 80, TCP> 和 <10.0.13.3, 90, TCP>是不冲突的。</li>
</ol>
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<h3 id="配置文件"><a href="#配置文件" class="headerlink" title="配置文件"></a>配置文件</h3><p>选择oh my zsh的原因在于它提供了很多插件和主题。</p>
<p>zsh的配置文件为：<code>~/.zshrc</code>，oh my zsh的许多配置也在此添加。</p>
<h3 id="主题"><a href="#主题" class="headerlink" title="主题"></a>主题</h3><p>习惯使用<a target="_blank" rel="noopener" href="https://github.com/ohmyzsh/ohmyzsh/blob/master/themes/gallois.zsh-theme">gallois主题</a>，但发现它有一个现在无法忍受的缺点，如果当前目录是git仓库，它会在右边显示分支名称和clean状态。当从终端复制文本出来时，分支名称和左边命令的空白，全是空格填充，复制出来就得手动删除。</p>
<p><img src="https://lessisbetter.site/images/2020-11-old-gallois.png"></p>
<p>oh my zsh的所有主题配置都在<code>.oh-my-zsh/themes/</code>目录，文件名称同主题名称，可以对这些主题的一些配置进行修改。</p>
<p>注释掉配置文件中关于git的设置，打开新终端后，就可以不显示git分支信息了。</p>
<p><img src="https://lessisbetter.site/images/2020-11-new-gallois.png"></p>
<p>从此复制出的代码，在也没有多余文本。</p>
<h3 id="插件"><a href="#插件" class="headerlink" title="插件"></a>插件</h3><p>插件目录在：<code>~/.oh-my-zsh/plugins</code>，从中可以浏览自己需要的插件。</p>
<p>比如我常用的插件为：<code>plugins=(git autojump docker kubectl extract)</code>，添加到<code>~/.zshrc</code>即可。</p>
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<h3 id="kustomize简介"><a href="#kustomize简介" class="headerlink" title="kustomize简介"></a>kustomize简介</h3><p><a target="_blank" rel="noopener" href="https://github.com/kubernetes-sigs/kustomize">kustomize</a>是一个自定义管理原始的YAML模板资源文件的工具，同时无需修改原始的YAML文件。</p>
<p>对于kustomize的理解是，它借助了docker镜像的类似概念：可以一层层的进行覆盖。</p>
<p>Kustmoize有Base和Overlay 2个概念，被依赖的层成为base，当前进行覆盖操作的层成为overlay。所以1个overlay，也可以是另外overlay的base。</p>
<p><img src="https://lessisbetter.site/images/2020-11-kustomize-base-overlay.png" alt="Kustomize base和overlay"></p>
<p>在kubectl v1.14之后，其中融合了kustomize，也就说如果安装了kubectl无需安装kustomize，即可使用kustomize。</p>
<p>把kustmoize的资源文件部署到集群有2个办法：</p>
<ol>
<li>通过kubectl内置的kustomize：<code>kubectl apply -k $KUSTOMIZE_DIR</code> 应用到集群。</li>
<li>集合kustomize和kubectl: <code>kustomize build $KUSTOMIZE_DIR | kubectl apply -f -</code>应用到集群。</li>
</ol>
<h3 id="base"><a href="#base" class="headerlink" title="base"></a>base</h3><p>nginx-deployment.yaml:</p>
<figure class="highlight yaml"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br></pre></td><td class="code"><pre><span class="line"><span class="attr">apiVersion:</span> <span class="string">apps/v1</span></span><br><span class="line"><span class="attr">kind:</span> <span class="string">Deployment</span></span><br><span class="line"><span class="attr">metadata:</span></span><br><span class="line"> <span class="attr">name:</span> <span class="string">nginx</span></span><br><span class="line"> <span class="attr">labels:</span></span><br><span class="line"> <span class="attr">app:</span> <span class="string">nginx</span></span><br><span class="line"><span class="attr">spec:</span></span><br><span class="line"> <span class="attr">selector:</span></span><br><span class="line"> <span class="attr">matchLabels:</span></span><br><span class="line"> <span class="attr">app:</span> <span class="string">nginx</span></span><br><span class="line"> <span class="attr">template:</span></span><br><span class="line"> <span class="attr">metadata:</span></span><br><span class="line"> <span class="attr">labels:</span></span><br><span class="line"> <span class="attr">app:</span> <span class="string">nginx</span></span><br><span class="line"> <span class="attr">spec:</span></span><br><span class="line"> <span class="attr">containers:</span></span><br><span class="line"> <span class="bullet">-</span> <span class="attr">image:</span> <span class="string">nginx:1.9.1</span></span><br><span class="line"> <span class="attr">name:</span> <span class="string">nginx</span></span><br><span class="line"> <span class="attr">ports:</span></span><br><span class="line"> <span class="bullet">-</span> <span class="attr">containerPort:</span> <span class="number">80</span></span><br><span class="line"> <span class="attr">name:</span> <span class="string">http</span></span><br><span class="line"> <span class="attr">volumeMounts:</span></span><br><span class="line"> <span class="bullet">-</span> <span class="attr">mountPath:</span> <span class="string">/user/share/nginx/html</span></span><br><span class="line"> <span class="attr">name:</span> <span class="string">data</span></span><br><span class="line"> <span class="attr">restartPolicy:</span> <span class="string">Always</span></span><br><span class="line"> <span class="attr">volumes:</span></span><br><span class="line"> <span class="bullet">-</span> <span class="attr">name:</span> <span class="string">data</span></span><br><span class="line"> <span class="attr">emptyDir:</span> {}</span><br></pre></td></tr></table></figure>
<p>kustomization.yaml :</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">commonLabels:</span><br><span class="line"> app: kustomize-nginx</span><br><span class="line"></span><br><span class="line">resources:</span><br><span class="line">- nginx-deployment.yaml</span><br></pre></td></tr></table></figure>
<p>build的效果就是，把列出来的resources中的label，都换成<code>app: kustomize-nginx</code>:</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br></pre></td><td class="code"><pre><span class="line">$ diff <(kustomize build .) nginx-deployment.yaml</span><br><span class="line">4,5d3</span><br><span class="line">< labels:</span><br><span class="line">< app: kustomize-nginx</span><br><span class="line">6a5,6</span><br><span class="line">> labels:</span><br><span class="line">> app: nginx</span><br><span class="line">10c10</span><br><span class="line">< app: kustomize-nginx</span><br><span class="line">---</span><br><span class="line">> app: nginx</span><br><span class="line">14c14</span><br><span class="line">< app: kustomize-nginx</span><br><span class="line">---</span><br><span class="line">> app: nginx</span><br><span class="line">17,24c17,24</span><br><span class="line">< - image: nginx:1.9.1</span><br><span class="line">< name: nginx</span><br><span class="line">< ports:</span><br><span class="line">< - containerPort: 80</span><br><span class="line">< name: http</span><br><span class="line">< volumeMounts:</span><br><span class="line">< - mountPath: /user/share/nginx/html</span><br><span class="line">< name: data</span><br><span class="line">---</span><br><span class="line">> - image: nginx:1.9.1</span><br><span class="line">> name: nginx</span><br><span class="line">> ports:</span><br><span class="line">> - containerPort: 80</span><br><span class="line">> name: http</span><br><span class="line">> volumeMounts:</span><br><span class="line">> - mountPath: /user/share/nginx/html</span><br><span class="line">> name: data</span><br><span class="line">27,28c27,28</span><br><span class="line">< - emptyDir: {}</span><br><span class="line">< name: data</span><br><span class="line">---</span><br><span class="line">> - name: data</span><br><span class="line">> emptyDir: {}</span><br></pre></td></tr></table></figure>
<p>应用到k8s，并且查看label。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br></pre></td><td class="code"><pre><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/base]$ kubectl apply -k .</span><br><span class="line">deployment.apps/nginx created</span><br><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/base]$ kubectl get deploy -o wide</span><br><span class="line">NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR</span><br><span class="line">nginx 1/1 1 1 7s nginx nginx:1.9.1 app=kustomize-nginx</span><br></pre></td></tr></table></figure>
<h3 id="overlay"><a href="#overlay" class="headerlink" title="overlay"></a>overlay</h3><h4 id="修改副本数量"><a href="#修改副本数量" class="headerlink" title="修改副本数量"></a>修改副本数量</h4><p>kustomization.yaml:</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><span class="line">namePrefix: testing-</span><br><span class="line">commonLabels:</span><br><span class="line"> app: kustomize-nginx</span><br><span class="line"> variant: testing</span><br><span class="line"> group: test</span><br><span class="line"></span><br><span class="line">bases: </span><br><span class="line">- ../../base</span><br><span class="line"></span><br><span class="line">patchesStrategicMerge:</span><br><span class="line">- nginx-deployment.yaml</span><br><span class="line"></span><br></pre></td></tr></table></figure>
<ul>
<li><p><code>namePrefix</code>: 资源前缀，比如deployment名称以<code>namePrefix: testing-</code>开头。</p>
</li>
<li><p><code>commonLabels</code>：会使用的标签</p>
</li>
<li><p><code>bases</code>：所基于的base文件</p>
</li>
<li><p><code>patchesStrategicMerge</code>：用合并的方式做path，列出涉及的文件。</p>
</li>
</ul>
<p>nginx-deployment.yaml 为patch的内容：</p>
<figure class="highlight yaml"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line"><span class="attr">apiVersion:</span> <span class="string">apps/v1</span></span><br><span class="line"><span class="attr">kind:</span> <span class="string">Deployment</span></span><br><span class="line"><span class="attr">metadata:</span></span><br><span class="line"> <span class="attr">name:</span> <span class="string">nginx</span></span><br><span class="line"><span class="attr">spec:</span></span><br><span class="line"> <span class="attr">replicas:</span> <span class="number">2</span></span><br></pre></td></tr></table></figure>
<p>名称<code>metadata.name</code>应当与base中的名称相同，因为使用名称做匹配，所做的patch是当前overlay，名为nginx的deployment的副本数量为2。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br></pre></td><td class="code"><pre><span class="line">$ kubectl apply -k .</span><br><span class="line">deployment.apps/testing-nginx created</span><br><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/overlay/testing]$</span><br><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/overlay/testing]$ kubectl get deployment</span><br><span class="line">NAME READY UP-TO-DATE AVAILABLE AGE</span><br><span class="line">nginx 1/1 1 1 19m</span><br><span class="line">testing-nginx 2/2 2 2 8s</span><br></pre></td></tr></table></figure>
<h4 id="覆盖镜像"><a href="#覆盖镜像" class="headerlink" title="覆盖镜像"></a>覆盖镜像</h4><p>kustomization.yaml:</p>
<ul>
<li>前缀设置为develop，更新相应tag</li>
<li>通过<code>images</code>更新镜像</li>
<li>Nginx deployment的副本数量修改为5，这种方式与<a href="#%E4%BF%AE%E6%94%B9%E5%89%AF%E6%9C%AC%E6%95%B0%E9%87%8F">上一个修改副本数量</a>相比更简洁。</li>
</ul>
<figure class="highlight yaml"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br></pre></td><td class="code"><pre><span class="line"><span class="attr">namePrefix:</span> <span class="string">dev-</span></span><br><span class="line"><span class="attr">commonLabels:</span></span><br><span class="line"> <span class="attr">app:</span> <span class="string">dev-nginx</span></span><br><span class="line"> <span class="attr">variant:</span> <span class="string">dev</span></span><br><span class="line"> <span class="attr">group:</span> <span class="string">develop</span></span><br><span class="line"></span><br><span class="line"><span class="attr">bases:</span></span><br><span class="line"> <span class="bullet">-</span> <span class="string">../../base</span></span><br><span class="line"><span class="attr">images:</span></span><br><span class="line"> <span class="bullet">-</span> <span class="attr">name:</span> <span class="string">nginx</span></span><br><span class="line"> <span class="attr">newTag:</span> <span class="number">1.19</span><span class="number">.0</span></span><br><span class="line"><span class="attr">replicas:</span></span><br><span class="line"> <span class="bullet">-</span> <span class="attr">name:</span> <span class="string">nginx</span></span><br><span class="line"> <span class="attr">count:</span> <span class="number">5</span></span><br><span class="line"></span><br></pre></td></tr></table></figure>
<p>部署到集群：发现kubectl内置的kustomize的<code>replicas</code>并没有得到支持，可能是内置的kustomize版本较老，使用kustomize + kubectl的方式可以部署到集群。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/overlay]$ kubectl delete -k develop</span><br><span class="line">error: json: unknown field "replicas"</span><br><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/overlay]$ kustomize build develop | kubectl apply -f -</span><br><span class="line">deployment.apps/dev-nginx created</span><br><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/overlay]$</span><br><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/overlay]$ kubectl get deploy -o wide</span><br><span class="line">NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR</span><br><span class="line">dev-nginx 5/5 5 5 17s nginx nginx:1.19.0 app=dev-nginx,group=develop,variant=dev</span><br><span class="line">nginx 1/1 1 1 10h nginx nginx:1.9.1 app=kustomize-nginx</span><br><span class="line">testing-nginx 2/2 2 2 10h nginx nginx:1.9.1 app=kustomize-nginx,group=test,variant=testing</span><br></pre></td></tr></table></figure>
<p><a target="_blank" rel="noopener" href="https://kubectl.docs.kubernetes.io/references/kustomize/images/">https://kubectl.docs.kubernetes.io/references/kustomize/images/</a></p>
<h4 id="更多功能"><a href="#更多功能" class="headerlink" title="更多功能"></a>更多功能</h4><p>参考<a target="_blank" rel="noopener" href="https://kubectl.docs.kubernetes.io/zh/api-reference/kustomization/bases/">kustomize reference</a>。</p>
<h3 id="kustomize常用命令"><a href="#kustomize常用命令" class="headerlink" title="kustomize常用命令"></a>kustomize常用命令</h3><h4 id="build"><a href="#build" class="headerlink" title="build"></a>build</h4><p>使用配置文件生成资源的YAML文件，并打印到标准输出。配合kubectl命令可以把资源部署到集群。</p>
<h4 id="edit"><a href="#edit" class="headerlink" title="edit"></a>edit</h4><p>通过命令行修改<code>kustomization.yaml</code>文件。这种办法可以方便的放到脚本中去修改<code>kustomization.yaml</code>，而不是手动去修改。比如operator-sdk的样例，通过edit命令指定资源所要使用的镜像。</p>
<p><strong>edit的set命令</strong>可以做以下几样事：</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br></pre></td><td class="code"><pre><span class="line">Available Commands:</span><br><span class="line"> image Sets images and their new names, new tags or digests in the kustomization file</span><br><span class="line"> nameprefix Sets the value of the namePrefix field in the kustomization file.</span><br><span class="line"> namespace Sets the value of the namespace field in the kustomization file</span><br><span class="line"> namesuffix Sets the value of the nameSuffix field in the kustomization file.</span><br><span class="line"> replicas Sets replicas count for resources in the kustomization file</span><br></pre></td></tr></table></figure>
<p>通过命令行修改前缀和镜像：</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/overlay]$ cp -r develop develop-dabin</span><br><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/overlay/develop-dabin]$ kustomize edit set nameprefix "develop-dabin-"</span><br><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/overlay/develop-dabin]$ kustomize edit set image "nginx:1.18.0"</span><br><span class="line">[~/workspace/notes/kubernetes/examples/kustomize/overlay/develop-dabin]$ head kustomization.yaml</span><br><span class="line">namePrefix: develop-dabin-</span><br><span class="line">commonLabels:</span><br><span class="line"> app: dev-nginx</span><br><span class="line"> group: develop</span><br><span class="line"> variant: dev</span><br><span class="line"></span><br><span class="line">images:</span><br><span class="line">- name: nginx</span><br><span class="line"> newTag: 1.18.0</span><br><span class="line">replicas:</span><br></pre></td></tr></table></figure>
<p>edit命令除了set外，还有add、remove、fix，能够更加完整的通过命令编辑<code>kustomization.yaml</code>文件。</p>
<p>本文样例：<a target="_blank" rel="noopener" href="https://github.com/Shitaibin/notes/tree/master/kubernetes/examples/kustomize">examples/kustomize</a> 。</p>
<h3 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h3><ul>
<li><a target="_blank" rel="noopener" href="https://kubectl.docs.kubernetes.io/references/kustomize/nameprefix/">kustomization.yaml的写法</a></li>
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<h3 id="JSONPath基础"><a href="#JSONPath基础" class="headerlink" title="JSONPath基础"></a>JSONPath基础</h3><p>XML有一个非常强大的解析工具是XPath，用于提取XML中的内容。之后也出现了一种高效提取JSON内容的工具，它被称为JSONPath。</p>
<p>JSONPath现在有很多不同的实现，不同的实现支持的提取语法略有不同，比如Goessner的JSONPath如下：</p>
<p><img src="https://lessisbetter.site/images/2020-11-goessner-jsonpath.png" alt="goessner jsonpath"></p>
<p><a target="_blank" rel="noopener" href="https://github.com/alibaba/fastjson/wiki/JSONPath#3-%E6%94%AF%E6%8C%81%E8%AF%AD%E6%B3%95">fastjson的JSONPath</a>支持的更加丰富。</p>
<p>示例JSON内容：</p>
<figure class="highlight json"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br></pre></td><td class="code"><pre><span class="line">{</span><br><span class="line"> <span class="attr">"store"</span>: {</span><br><span class="line"> <span class="attr">"book"</span>: [</span><br><span class="line"> {</span><br><span class="line"> <span class="attr">"category"</span>: <span class="string">"reference"</span>,</span><br><span class="line"> <span class="attr">"author"</span>: <span class="string">"Nigel Rees"</span>,</span><br><span class="line"> <span class="attr">"title"</span>: <span class="string">"Sayings of the Century"</span>,</span><br><span class="line"> <span class="attr">"price"</span>: <span class="number">8.95</span></span><br><span class="line"> },</span><br><span class="line"> {</span><br><span class="line"> <span class="attr">"category"</span>: <span class="string">"fiction"</span>,</span><br><span class="line"> <span class="attr">"author"</span>: <span class="string">"Evelyn Waugh"</span>,</span><br><span class="line"> <span class="attr">"title"</span>: <span class="string">"Sword of Honour"</span>,</span><br><span class="line"> <span class="attr">"price"</span>: <span class="number">12.99</span></span><br><span class="line"> },</span><br><span class="line"> {</span><br><span class="line"> <span class="attr">"category"</span>: <span class="string">"fiction"</span>,</span><br><span class="line"> <span class="attr">"author"</span>: <span class="string">"Herman Melville"</span>,</span><br><span class="line"> <span class="attr">"title"</span>: <span class="string">"Moby Dick"</span>,</span><br><span class="line"> <span class="attr">"isbn"</span>: <span class="string">"0-553-21311-3"</span>,</span><br><span class="line"> <span class="attr">"price"</span>: <span class="number">8.99</span></span><br><span class="line"> },</span><br><span class="line"> {</span><br><span class="line"> <span class="attr">"category"</span>: <span class="string">"fiction"</span>,</span><br><span class="line"> <span class="attr">"author"</span>: <span class="string">"J. R. R. Tolkien"</span>,</span><br><span class="line"> <span class="attr">"title"</span>: <span class="string">"The Lord of the Rings"</span>,</span><br><span class="line"> <span class="attr">"isbn"</span>: <span class="string">"0-395-19395-8"</span>,</span><br><span class="line"> <span class="attr">"price"</span>: <span class="number">22.99</span></span><br><span class="line"> }</span><br><span class="line"> ],</span><br><span class="line"> <span class="attr">"bicycle"</span>: {</span><br><span class="line"> <span class="attr">"color"</span>: <span class="string">"red"</span>,</span><br><span class="line"> <span class="attr">"price"</span>: <span class="number">19.95</span></span><br><span class="line"> }</span><br><span class="line"> },</span><br><span class="line"> <span class="attr">"expensive"</span>: <span class="number">10</span></span><br><span class="line">}</span><br></pre></td></tr></table></figure>
<p>以例子讲解几个最常用的语法：</p>
<table>
<thead>
<tr>
<th>语法</th>
<th>语法含义</th>
<th>例子</th>
<th>例子含义</th>
</tr>
</thead>
<tbody><tr>
<td>$</td>
<td>JSON内容的根对象，所有的JSONPath都是以<code>$</code>为开头。</td>
<td><code>$</code></td>
<td><a target="_blank" rel="noopener" href="http://jsonpath.herokuapp.com/?path=$">JSON内容本身</a>。</td>
</tr>
<tr>
<td>.</td>
<td>后面跟子对象。</td>
<td><code>$.expensive</code></td>
<td><a target="_blank" rel="noopener" href="http://jsonpath.herokuapp.com/?path=$.expensive">提取根对象的expensive字段的值</a>。</td>
</tr>
<tr>
<td>..</td>
<td>递归扫描子对象。</td>
<td><code>$..price</code></td>
<td><a target="_blank" rel="noopener" href="http://jsonpath.herokuapp.com/?path=$..price">提取对象中所有price字段的值，结果会包含所有book和bicycle中的价格</a>。</td>
</tr>
<tr>
<td>[num]</td>
<td>以下标访问数组。语法类似Python，num为负数时，代表倒数。</td>
<td><code>$.store.book[0]</code></td>
<td><a target="_blank" rel="noopener" href="http://jsonpath.herokuapp.com/?path=$.store.book%5B0%5D">获取第一本书</a>。</td>
</tr>
<tr>
<td>[num1, num2,num3]</td>
<td>以下标获取数据中多个数据。</td>
<td><code>$.store.book[0,2]</code></td>
<td><a target="_blank" rel="noopener" href="http://jsonpath.herokuapp.com/?path=$.store.book%5B0,2%5D">获取第1、3本书</a>。</td>
</tr>
<tr>
<td>[start:end]</td>
<td>获取数组区间[start, end)的数据。</td>
<td><code>$.store.book[0:2]</code></td>
<td><a target="_blank" rel="noopener" href="http://jsonpath.herokuapp.com/?path=$.store.book%5B0:2%5D">获取前2本书</a>。</td>
</tr>
<tr>
<td>[start:end:step]</td>
<td>获取数组区间[start, end)的数据，但以step为步长提取数据。<strong>但不是所有JSONPath实现都支持</strong>。</td>
<td><code>$.store.book[0:3:2]</code></td>
<td>获取第1~3本书，以步长为2提取，也即是第1、3本书。</td>
</tr>
<tr>
<td>[*]</td>
<td>通配符，匹配所有子对象。</td>
<td><code>$.store.*.price</code></td>
<td><a target="_blank" rel="noopener" href="http://jsonpath.herokuapp.com/?path=$.store.*.price">匹配store子对象中的价格，因为book的价格，是更下一级，所以只能匹配到bicycle的价格</a>。</td>
</tr>
<tr>
<td>?()</td>
<td>过滤符，可以理解成SQL的Where。</td>
<td><code>$.store.[?(@.category=="fiction")].author</code></td>
<td><a target="_blank" rel="noopener" href="http://jsonpath.herokuapp.com/?path=$.store.%5B?(@.category==%22fiction%22).author%5D">获取类别为fiction的书籍作者列表</a>。</td>
</tr>
<tr>
<td>@</td>
<td>当前对象，配合<code>?()</code>很好用。</td>
<td></td>
<td></td>
</tr>
</tbody></table>
<h3 id="k8s使用jsonpath"><a href="#k8s使用jsonpath" class="headerlink" title="k8s使用jsonpath"></a>k8s使用jsonpath</h3><p>kubectl没有提供查看Pod内容器的名称，怎么办呢？可以利用jsonpath或者go template实现。</p>
<p>json格式输出结果通常是嵌套多层，使用jsonpath可以忽略中间层次，而go template不行，这是jsonpath比go template好用的地方。</p>
<p>看一个略微复杂k8s使用jsonpath列出所有pod的所有容器名称和镜像的样例：</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">kubectl get pods --all-namespaces -o=jsonpath='{range .items[*]}{"pod: "}{.metadata.name} {"\n"}{range .spec.containers[*]}{"\tcontainer: "}{.name}{"\n\timage: "}{.image}{"\n"}{end}{end}'</span><br></pre></td></tr></table></figure>
<p>发现<code>jsonpath=''</code>与标准的jsonpath并不一样：</p>
<ul>
<li>没有<code>$</code></li>
<li>一堆<code>{}</code></li>
<li>还有<code>range, {"\n"}</code>等</li>
</ul>
<p>那是因为<a target="_blank" rel="noopener" href="https://kubernetes.io/docs/reference/kubectl/jsonpath/">k8s对jsonpath的支持</a>有以下特性：</p>
<ol>
<li>在jsonpath中使用<code>""</code>包含文本，这样在输出的结果可以显示自定义的字符串，还能进行换行、Tab等。</li>
<li>支持使用<code>range .. end</code>迭代数组，原生的jsonpath没有办法提取数组元素中的多个子对象，使用range达成效果，比如想获得容器的名称镜像。</li>
<li>支持<code>-num</code>获取数组的倒数位置的元素</li>
<li>可以省略<code>$</code>，太好了</li>
<li>每一段jsonpath使用<code>{}</code>连接</li>
</ol>
<p>刚开始使用jsonpath时，有种眼花缭乱的感觉，我们就拆解下上面的样例jsonpath。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">kubectl get pods --all-namespaces -o=jsonpath='{.items[*].metadata.name}'</span><br></pre></td></tr></table></figure>
<p><img src="https://lessisbetter.site/images/2020-11-1-pod-name.png"></p>
<p>先提取每个pod的名称，这个还和原生的jsonpath一样。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">kubectl get pods --all-namespaces -o=jsonpath='{range .items[*]}{"pod: "}{.metadata.name}{"\n"}{end}'</span><br></pre></td></tr></table></figure>
<p><img src="https://lessisbetter.site/images/2020-11-2-pod-name-range.png"></p>
<p>因为每个pod还要取容器名称和镜像，所以最好每个pod占一行，我们需要使用<code>range .. end</code>处理每一个pod，列pod所含的容器。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">kubectl get pods --all-namespaces -o=jsonpath='{range .items[*]}{"pod: "}{.metadata.name}{"\n"}{"\tcontainer: "}{.spec.containers[*].name}, {.spec.containers[*].image}{"\n"}{end}'</span><br><span class="line"></span><br></pre></td></tr></table></figure>
<p><img src="https://lessisbetter.site/images/2020-11-3-pod-containers.png"></p>
<p>可以看到每个pod内可能包含多个容器，所以也得用<code>range .. end</code>去处理pod的每一个container。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br></pre></td><td class="code"><pre><span class="line">kubectl get pods --all-namespaces -o=jsonpath='{range .items[*]}{"pod: "}{.metadata.name} {"\n"}{range .spec.containers[*]}{"\tcontainer: "}{.name}{"\n\timage: "}{.image}{"\n"}{end}{end}'</span><br><span class="line"></span><br></pre></td></tr></table></figure>
<p><img src="https://lessisbetter.site/images/2020-11-4-pod-contianers-image.png"></p>
<p>上面提到使用jsonpath可以简化层级，因为<code>containers</code>这个名词在层级中是独有的，不像<code>name</code>可能是存在于多个层级，所以可以使用<code>..</code>简化：</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">kubectl get pods --all-namespaces -o=jsonpath='{range .items[*]}{"pod: "}{.metadata.name} {"\n"}{range ..containers[*]}{"\tcontainer: "}{.name}{"\n\timage: "}{.image}{"\n"}{end}{end}'</span><br></pre></td></tr></table></figure>
<p><img src="https://lessisbetter.site/images/2020-11-5-simplify-pod-containers.png"></p>
<p>最后看一下过滤的使用，只想列出<code>weave</code>的pod的容器和镜像：</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">kubectl get pods --all-namespaces -o=jsonpath='{range .items[?(@.metadata.name=="weave-net-sqjzh")]}{"pod: "}{.metadata.name} {"\n"}{range ..containers[*]}{"\tcontainer: "}{.name}{"\n\timage: "}{.image}{"\n"}{end}{end}'</span><br></pre></td></tr></table></figure>
<p><img src="https://lessisbetter.site/images/2020-11-6-pod-filter.png"></p>
<h3 id="练习"><a href="#练习" class="headerlink" title="练习"></a>练习</h3><p>使用JSONPath获取：</p>
<ol>
<li>Pod的名称和IP</li>
<li>Pod退出原因</li>
</ol>
<h3 id="参考资料"><a href="#参考资料" class="headerlink" title="参考资料"></a>参考资料</h3><ul>
<li><a target="_blank" rel="noopener" href="https://goessner.net/articles/JsonPath/">goessner: JSONPath - XPath for JSON</a></li>
<li><a target="_blank" rel="noopener" href="https://kubernetes.io/docs/reference/kubectl/jsonpath/">Kubernetes JSONPath Support</a>，<a target="_blank" rel="noopener" href="http://docs.kubernetes.org.cn/67.html">一个中文版本</a></li>
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<h2 id="模板"><a href="#模板" class="headerlink" title="模板"></a>模板</h2><figure class="highlight dockerfile"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment"># build时设置版本 --build-arg GO_VERSION=1.13，默认为go1.15</span></span><br><span class="line"><span class="keyword">ARG</span> GO_VERSION=<span class="number">1.15</span></span><br><span class="line"><span class="keyword">FROM</span> golang:${GO_VERSION} AS builder</span><br><span class="line"><span class="keyword">ENV</span> GOPROXY=<span class="string">"https://goproxy.cn"</span></span><br><span class="line"></span><br><span class="line"><span class="keyword">ENV</span> APP_PATH=<span class="string">"/app/goapp"</span></span><br><span class="line"><span class="keyword">WORKDIR</span><span class="bash"> <span class="string">"/app"</span></span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 拷贝构建文件</span></span><br><span class="line"><span class="keyword">COPY</span><span class="bash"> . .</span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 编译</span></span><br><span class="line"><span class="keyword">RUN</span><span class="bash"> go mod download</span></span><br><span class="line"><span class="keyword">RUN</span><span class="bash"> CGO_ENABLED=0 GOARCH=amd64 GOOS=linux go build -a -o <span class="variable">${APP_PATH}</span> .</span></span><br><span class="line"><span class="keyword">RUN</span><span class="bash"> ls </span></span><br><span class="line"></span><br><span class="line"></span><br><span class="line"><span class="comment"># 构建运行镜像</span></span><br><span class="line"><span class="keyword">FROM</span> alpine:<span class="number">3.10</span> AS final</span><br><span class="line"></span><br><span class="line"><span class="keyword">ENV</span> APP_PATH=<span class="string">"/app/goapp"</span></span><br><span class="line"><span class="keyword">WORKDIR</span><span class="bash"> <span class="string">"/app"</span></span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 拷贝程序，如有必要另外拷贝其他文件</span></span><br><span class="line"><span class="keyword">COPY</span><span class="bash"> --from=builder <span class="variable">${APP_PATH}</span> <span class="variable">${APP_PATH}</span> </span></span><br><span class="line"></span><br><span class="line"><span class="comment"># 运行程序</span></span><br><span class="line"><span class="keyword">ENTRYPOINT</span><span class="bash"> [<span class="string">"/app/goapp"</span>]</span></span><br></pre></td></tr></table></figure>
<p>构建命令：</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">docker build -t app:1.0 --build-arg GO_VERSION=1.13 .</span><br></pre></td></tr></table></figure>
<p>模板说明：</p>
<ol>
<li>构建命令不指定<code>--build-arg GO_VERSION=1.13</code>时，默认使用go1.15进行编译。</li>
<li>使用<code>alpine</code>作为运行基础镜像，减小镜像大小。</li>
<li>Dockerfile文件放到main.go所在目录。</li>
<li>把<code>goapp</code>替换成真正的程序名称。</li>
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<a href="/2020/11/10/dockerfile-arg/" class="post-title-link" itemprop="url">Dockerfile ARG指令</a>
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<p>Docker的文档关于<a target="_blank" rel="noopener" href="https://docs.docker.com/engine/reference/builder/#understand-how-arg-and-from-interact">ARG和FROM指令配合使用</a>做了详细说明：</p>
<p>ARG用于传入外部参数，定义在FROM指令前，FROM后的其他指令无法使用ARG定义的环境变量，如果FROM指令后的指令要使用ARG定义的值，需要在FROM后再次定义。如果FROM不使用定义的ARG，可以直接定义到FROM后。</p>
<h3 id="传递参数"><a href="#传递参数" class="headerlink" title="传递参数"></a>传递参数</h3><h3 id="定义在FROM前"><a href="#定义在FROM前" class="headerlink" title="定义在FROM前"></a>定义在FROM前</h3><figure class="highlight dockerfile"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">ARG</span> UBUNTU_VERSION=<span class="number">16.04</span></span><br><span class="line"><span class="keyword">FROM</span> ubuntu:${UBUNTU_VERSION}</span><br><span class="line"><span class="keyword">RUN</span><span class="bash"> env | grep UBUNTU_VERSION</span></span><br></pre></td></tr></table></figure>
<p>从结果可以看到FROM后的指令<strong>无法访问</strong>ARG定义的<code>UBUNTU_VERSION</code>。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line">$ docker build -t test:afterfrom .</span><br><span class="line">Sending build context to Docker daemon 37.38kB</span><br><span class="line">Step 1/3 : ARG UBUNTU_VERSION=16.04</span><br><span class="line">Step 2/3 : FROM ubuntu:${UBUNTU_VERSION}</span><br><span class="line"> ---> 4b22027ede29</span><br><span class="line">Step 3/3 : RUN env | grep UBUNTU_VERSION</span><br><span class="line"> ---> Running in 8e93ca5e376b</span><br><span class="line">The command '/bin/sh -c env | grep UBUNTU_VERSION' returned a non-zero code: 1</span><br></pre></td></tr></table></figure>
<h3 id="定义在FROM后"><a href="#定义在FROM后" class="headerlink" title="定义在FROM后"></a>定义在FROM后</h3><figure class="highlight dockerfile"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">ARG</span> UBUNTU_VERSION=<span class="number">16.04</span></span><br><span class="line"><span class="keyword">FROM</span> ubuntu:${UBUNTU_VERSION}</span><br><span class="line"><span class="keyword">ARG</span> UBUNTU_VERSION</span><br><span class="line"><span class="keyword">RUN</span><span class="bash"> env | grep UBUNTU_VERSION</span></span><br></pre></td></tr></table></figure>
<p>从结果可以看到FROM后的指令<strong>可以访问</strong>ARG定义的<code>UBUNTU_VERSION</code>。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br></pre></td><td class="code"><pre><span class="line">$ docker build -t test:afterfrom .</span><br><span class="line">Sending build context to Docker daemon 37.38kB</span><br><span class="line">Step 1/4 : ARG UBUNTU_VERSION=16.04</span><br><span class="line">Step 2/4 : FROM ubuntu:${UBUNTU_VERSION}</span><br><span class="line"> ---> 4b22027ede29</span><br><span class="line">Step 3/4 : ARG UBUNTU_VERSION</span><br><span class="line"> ---> Using cache</span><br><span class="line"> ---> e3bae0875e66</span><br><span class="line">Step 4/4 : RUN env | grep UBUNTU_VERSION</span><br><span class="line"> ---> Running in 02438aff1f75</span><br><span class="line">UBUNTU_VERSION=16.04</span><br><span class="line">Removing intermediate container 02438aff1f75</span><br><span class="line"> ---> 646eec496165</span><br><span class="line">Successfully built 646eec496165</span><br><span class="line">Successfully tagged test:afterfrom</span><br></pre></td></tr></table></figure>
<h3 id="传递多个ARG参数"><a href="#传递多个ARG参数" class="headerlink" title="传递多个ARG参数"></a>传递多个ARG参数</h3><figure class="highlight dockerfile"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">ARG</span> UBUNTU_VERSION=<span class="number">16.04</span></span><br><span class="line"><span class="keyword">ARG</span> FILE_NAME=test</span><br><span class="line"><span class="keyword">FROM</span> ubuntu:${UBUNTU_VERSION}</span><br><span class="line"></span><br><span class="line"><span class="keyword">ARG</span> FILE_NAME</span><br><span class="line"><span class="keyword">WORKDIR</span><span class="bash"> /<span class="built_in">test</span>/</span></span><br><span class="line"><span class="keyword">RUN</span><span class="bash"> touch <span class="variable">${FILE_NAME}</span></span></span><br><span class="line"><span class="keyword">RUN</span><span class="bash"> ls <span class="variable">${FILE_NAME}</span></span></span><br></pre></td></tr></table></figure>
<p>传递多个参数需要多次使用<code>--build-arg</code>，可以看到传递的<code>FILE_NAME=app</code>生效了，而不是默认值。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br></pre></td><td class="code"><pre><span class="line">$ docker build -t test:twoargs --build-arg UBUNTU_VERSION=18.04 --build-arg FILE_NAME=app .</span><br><span class="line">Sending build context to Docker daemon 37.38kB</span><br><span class="line">Step 1/7 : ARG UBUNTU_VERSION=16.04</span><br><span class="line">Step 2/7 : ARG FILE_NAME=test</span><br><span class="line">Step 3/7 : FROM ubuntu:${UBUNTU_VERSION}</span><br><span class="line">18.04: Pulling from library/ubuntu</span><br><span class="line">171857c49d0f: Pull complete</span><br><span class="line">419640447d26: Pull complete</span><br><span class="line">61e52f862619: Pull complete</span><br><span class="line">Digest: sha256:646942475da61b4ce9cc5b3fadb42642ea90e5d0de46111458e100ff2c7031e6</span><br><span class="line">Status: Downloaded newer image for ubuntu:18.04</span><br><span class="line"> ---> 56def654ec22</span><br><span class="line">Step 4/7 : ARG FILE_NAME</span><br><span class="line"> ---> Running in bee623328f35</span><br><span class="line">Removing intermediate container bee623328f35</span><br><span class="line"> ---> 52f803da2959</span><br><span class="line">Step 5/7 : WORKDIR /test/</span><br><span class="line"> ---> Running in fa4542584af1</span><br><span class="line">Removing intermediate container fa4542584af1</span><br><span class="line"> ---> 5ebd782db9b8</span><br><span class="line">Step 6/7 : RUN touch ${FILE_NAME}</span><br><span class="line"> ---> Running in 0cd5723b744d</span><br><span class="line">Removing intermediate container 0cd5723b744d</span><br><span class="line"> ---> 920c6bd75bab</span><br><span class="line">Step 7/7 : RUN ls ${FILE_NAME}</span><br><span class="line"> ---> Running in b94a33093ddf</span><br><span class="line">app</span><br><span class="line">Removing intermediate container b94a33093ddf</span><br><span class="line"> ---> 804bf831059a</span><br><span class="line">Successfully built 804bf831059a</span><br><span class="line">Successfully tagged test:twoargs</span><br></pre></td></tr></table></figure>
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<a href="/2020/09/28/misunderstanding-iowait/" class="post-title-link" itemprop="url">被误解的iowait</a>
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<p>有一个cpu指标叫<code>iowait</code>或者<code>wa</code>，在top、iostat、vmstat命令中都可以看到这一项。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br></pre></td><td class="code"><pre><span class="line">[~]$ top</span><br><span class="line">top - 08:58:06 up 26 days, 23:20, 1 user, load average: 0.07, 0.23, 0.26</span><br><span class="line">Tasks: 164 total, 1 running, 111 sleeping, 0 stopped, 0 zombie</span><br><span class="line">%Cpu(s): 2.5 us, 1.2 sy, 0.0 ni, 96.2 id, 0.1 wa, 0.0 hi, 0.1 si, 0.0 st</span><br><span class="line">KiB Mem : 8167548 total, 698220 free, 996640 used, 6472688 buff/cache</span><br><span class="line">KiB Swap: 0 total, 0 free, 0 used. 7061988 avail Mem</span><br><span class="line"></span><br><span class="line">[~]$ iostat</span><br><span class="line">Linux 4.15.0-112-generic (shitaibin-x) 09/28/20 _x86_64_ (4 CPU)</span><br><span class="line"></span><br><span class="line">avg-cpu: %user %nice %system %iowait %steal %idle</span><br><span class="line"> 1.02 0.00 0.55 0.86 0.00 97.56</span><br><span class="line"></span><br><span class="line">Device tps kB_read/s kB_wrtn/s kB_read kB_wrtn</span><br><span class="line">loop0 0.00 0.00 0.00 5 0</span><br><span class="line">vda 13.32 2.65 84.15 6182326 196098973</span><br><span class="line"></span><br><span class="line">[~]$</span><br><span class="line">[~]$</span><br><span class="line">[~]$ vmstat</span><br><span class="line">procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----</span><br><span class="line"> r b swpd free buff cache si so bi bo in cs us sy id wa st</span><br><span class="line"> 0 0 0 685616 177356 6306652 0 0 1 21 5 3 1 1 98 1 0</span><br></pre></td></tr></table></figure>
<p>这个指标的字面含义是等待IO的时间（百分比），很多人会认为这个指标暗示这IO瓶颈，然而这是有一定无解的，iowait高不一定有IO瓶颈。</p>
<figure class="highlight plain"><table><tr><td class="gutter"><pre><span class="line">1</span><br></pre></td><td class="code"><pre><span class="line">iowait = CPU空闲时间 / CPU总时间 ，前提CPU在等待至少一项IO操作完成</span><br></pre></td></tr></table></figure>
<p>所以它真正的含义是有未完成的IO操作时，CPU空闲的时间。</p>
<p>这2个资料都把iowait讲解的很清晰，并且举例iowait和IO瓶颈无关的例子。</p>
<ul>
<li><a target="_blank" rel="noopener" href="http://linuxperf.com/?p=33">理解iowait</a></li>
<li><a target="_blank" rel="noopener" href="https://www.inspurpower.com/upload/file/1583309942.pdf">浪潮：CPU iowait详解</a></li>
</ul>
<p>例子：</p>
<ul>
<li>低iowait，高IO的例子：IO高同时CPU计算也高，这样CPU的空闲时间少，造成iowait比较低，CPU密集掩盖了IO密集。</li>
<li>高iowait，低IO的例子：CPU计算很少，CPU基本空闲，但也有1个进程在IO，所以iowait高，但实际IO根本没任何瓶颈。</li>
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