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<!DOCTYPE HTML>
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<title>deployment controller 源码分析 · 田飞雨</title>
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<a href="https://blog.tianfeiyu.com" target="_blank" class="custom-link">Home</a>
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<li class="chapter " data-level="1.1" data-path="../">
<a href="../">
<b>1.1.</b>
Introduction
</a>
</li>
<li class="chapter " data-level="1.2" data-path="./">
<a href="./">
<b>1.2.</b>
kubernetes
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kube-apiserver 的设计与实现
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kube-apiserver 中 apiserver service 的实现
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<b>1.2.3.</b>
node controller 源码分析
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<b>1.2.4.</b>
job controller 源码分析
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<b>1.2.5.</b>
garbage collector controller 源码分析
</a>
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<li class="chapter " data-level="1.2.6" data-path="daemonset_controller.html">
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<b>1.2.6.</b>
daemonset controller 源码分析
</a>
</li>
<li class="chapter " data-level="1.2.7" data-path="statefulset_controller.html">
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<b>1.2.7.</b>
statefulset controller 源码分析
</a>
</li>
<li class="chapter active" data-level="1.2.8" data-path="deployment_controller.html">
<a href="deployment_controller.html">
<b>1.2.8.</b>
deployment controller 源码分析
</a>
</li>
<li class="chapter " data-level="1.2.9" data-path="replicaset_controller.html">
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<b>1.2.9.</b>
replicaset controller 源码分析
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<b>1.2.10.</b>
kube-scheduler 源码分析
</a>
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<li class="chapter " data-level="1.2.11" data-path="kube_scheduler_algorithm.html">
<a href="kube_scheduler_algorithm.html">
<b>1.2.11.</b>
kube-scheduler predicates 与 priorities 调度算法源码分析
</a>
</li>
<li class="chapter " data-level="1.2.12" data-path="kube_scheduler_preempt.html">
<a href="kube_scheduler_preempt.html">
<b>1.2.12.</b>
kube-scheduler 优先级与抢占机制源码分析
</a>
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<li class="chapter " data-level="1.2.13" data-path="k8s_service_theory.html">
<a href="k8s_service_theory.html">
<b>1.2.13.</b>
kubernetes service 原理解析
</a>
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<a href="kube_proxy_process.html">
<b>1.2.14.</b>
kube-proxy 源码分析
</a>
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<b>1.2.15.</b>
kube-proxy iptables 模式源码分析
</a>
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<a href="kube_proxy_ipvs.html">
<b>1.2.16.</b>
kube-proxy ipvs 模式源码分析
</a>
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<b>1.2.17.</b>
kubelet 架构浅析
</a>
</li>
<li class="chapter " data-level="1.2.18" data-path="kubelet_init.html">
<a href="kubelet_init.html">
<b>1.2.18.</b>
kubelet 启动流程分析
</a>
</li>
<li class="chapter " data-level="1.2.19" data-path="kubelet_create_pod.html">
<a href="kubelet_create_pod.html">
<b>1.2.19.</b>
kubelet 创建 pod 的流程
</a>
</li>
<li class="chapter " data-level="1.2.20" data-path="node_status.html">
<a href="node_status.html">
<b>1.2.20.</b>
kubelet 状态上报的方式
</a>
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<li class="chapter " data-level="1.2.21" data-path="k8s_events.html">
<a href="k8s_events.html">
<b>1.2.21.</b>
kubelet 中事件处理机制
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<li class="chapter " data-level="1.2.22" data-path="kubelet_status_manager.html">
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<b>1.2.22.</b>
kubelet statusManager 源码分析
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<b>1.2.23.</b>
kubernetes 中 Qos 的设计与实现
</a>
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<li class="chapter " data-level="1.2.24" data-path="kubelet_garbage_collect.html">
<a href="kubelet_garbage_collect.html">
<b>1.2.24.</b>
kubelet 中垃圾回收机制的设计与实现
</a>
</li>
<li class="chapter " data-level="1.2.25" data-path="k8s_evicted.html">
<a href="k8s_evicted.html">
<b>1.2.25.</b>
kubernetes 中 Evicted pod 是如何产生的
</a>
</li>
<li class="chapter " data-level="1.2.26" data-path="kubernetes_descheduler.html">
<a href="kubernetes_descheduler.html">
<b>1.2.26.</b>
Kubernetes 中 Descheduler 组件的使用与扩展
</a>
</li>
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<li class="chapter " data-level="1.3" data-path="../knative/">
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<b>1.3.</b>
knative
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<b>1.3.1.</b>
在 minkube 上部署 knative
</a>
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<li class="chapter " data-level="1.3.2" data-path="../knative/knative_serving.html">
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<b>1.3.2.</b>
knative serving 组件分析
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cgroup
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blkio cgroup
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<li class="chapter " data-level="1.4.2" data-path="../cgroup/pid_cgroup.html">
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<b>1.4.2.</b>
pid cgroup
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go
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golang 中函数使用值返回与指针返回的区别，底层原理分析
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Golang 程序启动流程分析
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Golang GPM 模型剖析
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<li><a href="#deployment-的功能">deployment 的功能</a><ul>
<li><a href="#deploymentreplicaset-和-pod-之间的关系">deployment、replicaSet 和 pod 之间的关系</a></li>
<li><a href="#deployment-的基本功能">deployment 的基本功能</a><ul>
<li><a href="#创建">创建</a></li>
<li><a href="#滚动更新">滚动更新</a></li>
<li><a href="#回滚">回滚</a></li>
<li><a href="#扩缩容">扩缩容</a></li>
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</ul>
</li>
</ul>
</li>
<li><a href="#deployment-controller-源码分析">deployment controller 源码分析</a><ul>
<li><a href="#deployment-controller-启动流程">deployment controller 启动流程</a></li>
<li><a href="#删除-1">删除</a></li>
<li><a href="#暂停和恢复">暂停和恢复</a></li>
<li><a href="#回滚-1">回滚</a></li>
<li><a href="#扩缩容-1">扩缩容</a></li>
<li><a href="#滚动更新-1">滚动更新</a><ul>
<li><a href="#滚动更新示例">滚动更新示例</a></li>
</ul>
</li>
<li><a href="#重新创建">重新创建</a></li>
</ul>
</li>
<li><a href="#总结">总结</a></li>
</ul>
<p>在前面的文章中已经分析过 kubernetes 中多个组件的源码了，本章会继续解读 kube-controller-manager 源码，kube-controller-manager 中有数十个 controller，本文会分析最常用到的 deployment controller。</p>
<h3 id="deployment-的功能"><a name="deployment-的功能" class="anchor-navigation-ex-anchor" href="#deployment-的功能"><i class="fa fa-link" aria-hidden="true"></i></a>deployment 的功能</h3>
<p>deployment 是 kubernetes 中用来部署无状态应用的一个对象，也是最常用的一种对象。</p>
<h4 id="deployment、replicaset-和-pod-之间的关系"><a name="deployment、replicaset-和-pod-之间的关系" class="anchor-navigation-ex-anchor" href="#deployment、replicaset-和-pod-之间的关系"><i class="fa fa-link" aria-hidden="true"></i></a>deployment、replicaSet 和 pod 之间的关系</h4>
<p>deployment 的本质是控制 replicaSet，replicaSet 会控制 pod，然后由 controller 驱动各个对象达到期望状态。</p>
<p><img src="http://cdn.tianfeiyu.com/deployment.png" alt=""></p>
<p>DeploymentController 是 Deployment 资源的控制器，其通过 DeploymentInformer、ReplicaSetInformer、PodInformer 监听三种资源，当三种资源变化时会触发 DeploymentController 中的 syncLoop 操作。</p>
<h4 id="deployment-的基本功能"><a name="deployment-的基本功能" class="anchor-navigation-ex-anchor" href="#deployment-的基本功能"><i class="fa fa-link" aria-hidden="true"></i></a>deployment 的基本功能</h4>
<p>下面通过命令行操作展示一下 deployment 的基本功能。</p>
<p>以下是 deployment 的一个示例文件：</p>
<pre class="language-"><code>apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
spec:
progressDeadlineSeconds: 600 // 执行操作的超时时间
replicas: 20
revisionHistoryLimit: 10 // 保存的历史版本数量
selector:
matchLabels:
app: nginx-deployment
strategy:
rollingUpdate:
maxSurge: 25% // 升级过程中最多可以比原先设置多出的 pod 数量
maxUnavailable: 25% // 升级过程中最多有多少个 pod 处于无法提供服务的状态
type: RollingUpdate // 更新策略
template:
metadata:
labels:
app: nginx-deployment
spec:
containers:
- name: nginx-deployment
image: nginx:1.9
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
</code></pre><h5 id="创建"><a name="创建" class="anchor-navigation-ex-anchor" href="#创建"><i class="fa fa-link" aria-hidden="true"></i></a>创建</h5>
<pre class="language-"><code>$ kubectl create -f nginx-dep.yaml --record
$ kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
nginx-deployment 20/20 20 20 22h
$ kubectl get rs
NAME DESIRED CURRENT READY AGE
nginx-deployment-68b649bd8b 20 20 20 22h
</code></pre><h5 id="滚动更新"><a name="滚动更新" class="anchor-navigation-ex-anchor" href="#滚动更新"><i class="fa fa-link" aria-hidden="true"></i></a>滚动更新</h5>
<pre class="language-"><code>$ kubectl set image deploy/nginx-deployment nginx-deployment=nginx:1.9.3
$ kubectl rollout status deployment/nginx-deployment
</code></pre><h5 id="回滚"><a name="回滚" class="anchor-navigation-ex-anchor" href="#回滚"><i class="fa fa-link" aria-hidden="true"></i></a>回滚</h5>
<pre class="language-"><code>// 查看历史版本
$ kubectl rollout history deployment/nginx-deployment
deployment.extensions/nginx-deployment
REVISION CHANGE-CAUSE
4 <span class="token tag"><span class="token tag"><span class="token punctuation"><</span>none</span><span class="token punctuation">></span></span>
5 <span class="token tag"><span class="token tag"><span class="token punctuation"><</span>none</span><span class="token punctuation">></span></span>
// 指定版本回滚
$ kubectl rollout undo deployment/nginx-deployment --to-revision=2
</code></pre><h5 id="扩缩容"><a name="扩缩容" class="anchor-navigation-ex-anchor" href="#扩缩容"><i class="fa fa-link" aria-hidden="true"></i></a>扩缩容</h5>
<pre class="language-"><code>$ kubectl scale deployment nginx-deployment --replicas 10
deployment.extensions/nginx-deployment scaled
</code></pre><h5 id="暂停与恢复"><a name="暂停与恢复" class="anchor-navigation-ex-anchor" href="#暂停与恢复"><i class="fa fa-link" aria-hidden="true"></i></a>暂停与恢复</h5>
<pre class="language-"><code>$ kubectl rollout pause deployment/nginx-deployment
$ kubectl rollout resume deploy nginx-deployment
</code></pre><h5 id="删除"><a name="删除" class="anchor-navigation-ex-anchor" href="#删除"><i class="fa fa-link" aria-hidden="true"></i></a>删除</h5>
<pre class="language-"><code>$ kubectl delete deployment nginx-deployment
</code></pre><p>以上是 deployment 的几个常用操作，下面会结合源码分析这几个操作都是如何实现的。</p>
<h3 id="deployment-controller-源码分析"><a name="deployment-controller-源码分析" class="anchor-navigation-ex-anchor" href="#deployment-controller-源码分析"><i class="fa fa-link" aria-hidden="true"></i></a>deployment controller 源码分析</h3>
<blockquote>
<p>kubernetes 版本：v1.16</p>
</blockquote>
<p>在控制器模式下，每次操作对象都会触发一次事件，然后 controller 会进行一次 syncLoop 操作，controller 是通过 informer 监听事件以及进行 ListWatch 操作的，关于 informer 的基础知识可以参考以前写的文章。</p>
<h4 id="deployment-controller-启动流程"><a name="deployment-controller-启动流程" class="anchor-navigation-ex-anchor" href="#deployment-controller-启动流程"><i class="fa fa-link" aria-hidden="true"></i></a>deployment controller 启动流程</h4>
<p>kube-controller-manager 中所有 controller 的启动都是在 <code>Run</code> 方法中完成初始化并启动的。在 <code>Run</code> 中会调用 run 函数，run 函数的主要流程有：</p>
<ul>
<li>1、调用 <code>NewControllerInitializers</code> 初始化所有 controller</li>
<li>2、调用 <code>StartControllers</code> 启动所有 controller</li>
</ul>
<p><code>k8s.io/kubernetes/cmd/kube-controller-manager/app/controllermanager.go:158</code></p>
<pre class="language-"><code>func Run(c *config.CompletedConfig, stopCh <-chan struct{}) error {
......
run := func(ctx context.Context) {
......
// 1.调用 NewControllerInitializers 初始化所有 controller
// 2.调用 StartControllers 启动所有 controller
if err := StartControllers(controllerContext, saTokenControllerInitFunc, NewControllerInitializers(controllerContext.LoopMode), unsecuredMux); err != nil {
klog.Fatalf("error starting controllers: %v", err)
}
......
select {}
}
......
}
</code></pre><p><code>NewControllerInitializers</code> 中定义了所有的 controller 以及 start controller 对应的方法。deployment controller 对应的启动方法是 <code>startDeploymentController</code>。</p>
<p><code>k8s.io/kubernetes/cmd/kube-controller-manager/app/controllermanager.go:373</code></p>
<pre class="language-"><code>func NewControllerInitializers(loopMode ControllerLoopMode) map[string]InitFunc {
controllers := map[string]InitFunc{}
......
controllers["deployment"] = startDeploymentController
......
}
</code></pre><p>在<code>startDeploymentController</code> 中对 deploymentController 进行了初始化，并执行 <code>dc.Run()</code> 方法启动了 controller。</p>
<p><code>k8s.io/kubernetes/cmd/kube-controller-manager/app/apps.go:82</code></p>
<pre class="language-"><code>func startDeploymentController(ctx ControllerContext) (http.Handler, bool, error) {
......
// 初始化 controller
dc, err := deployment.NewDeploymentController(
ctx.InformerFactory.Apps().V1().Deployments(),
ctx.InformerFactory.Apps().V1().ReplicaSets(),
ctx.InformerFactory.Core().V1().Pods(),
ctx.ClientBuilder.ClientOrDie("deployment-controller"),
)
......
// 启动 controller
go dc.Run(int(ctx.ComponentConfig.DeploymentController.ConcurrentDeploymentSyncs), ctx.Stop)
return nil, true, nil
}
</code></pre><p><code>ctx.ComponentConfig.DeploymentController.ConcurrentDeploymentSyncs</code> 指定了 deployment controller 中工作的 goroutine 数量，默认值为 5，即会启动五个 goroutine 从 workqueue 中取出 object 并进行 sync 操作，该参数的默认值定义在 <code>k8s.io/kubernetes/pkg/controller/deployment/config/v1alpha1/defaults.go</code> 中。</p>
<p><code>dc.Run</code> 方法会执行 ListWatch 操作并根据对应的事件执行 syncLoop。</p>