|
| 1 | +--- |
| 2 | +title: 探索 Pod 及其端点的终止行为 |
| 3 | +content_type: tutorial |
| 4 | +weight: 60 |
| 5 | +--- |
| 6 | +<!-- |
| 7 | +title: Explore Termination Behavior for Pods And Their Endpoints |
| 8 | +content_type: tutorial |
| 9 | +weight: 60 |
| 10 | +--> |
| 11 | + |
| 12 | +<!-- overview --> |
| 13 | + |
| 14 | +<!-- |
| 15 | +Once you connected your Application with Service following steps |
| 16 | +like those outlined in [Connecting Applications with Services](/docs/tutorials/services/connect-applications-service/), |
| 17 | +you have a continuously running, replicated application, that is exposed on a network. |
| 18 | +This tutorial helps you look at the termination flow for Pods and to explore ways to implement |
| 19 | +graceful connection draining. |
| 20 | +--> |
| 21 | +一旦你参照[使用 Service 连接到应用](/zh-cn/docs/tutorials/services/connect-applications-service/)中概述的那些步骤使用 |
| 22 | +Service 连接到了你的应用,你就有了一个持续运行的多副本应用暴露在了网络上。 |
| 23 | +本教程帮助你了解 Pod 的终止流程,探索实现连接排空的几种方式。 |
| 24 | + |
| 25 | +<!-- body --> |
| 26 | + |
| 27 | +<!-- |
| 28 | +## Termination process for Pods and their endpoints |
| 29 | +
|
| 30 | +There are often cases when you need to terminate a Pod - be it for upgrade or scale down. |
| 31 | +In order to improve application availability, it may be important to implement |
| 32 | +a proper active connections draining. |
| 33 | +
|
| 34 | +This tutorial explains the flow of Pod termination in connection with the |
| 35 | +corresponding endpoint state and removal by using |
| 36 | +a simple nginx web server to demonstrate the concept. |
| 37 | +--> |
| 38 | +## Pod 及其端点的终止过程 {#termination-process-for-pods-and-endpoints} |
| 39 | + |
| 40 | +你经常会遇到需要终止 Pod 的场景,例如为了升级或缩容。 |
| 41 | +为了改良应用的可用性,实现一种合适的活跃连接排空机制变得重要。 |
| 42 | + |
| 43 | +本教程将通过使用一个简单的 nginx Web 服务器演示此概念, |
| 44 | +解释 Pod 终止的流程及其与相应端点状态和移除的联系。 |
| 45 | + |
| 46 | +<!-- body --> |
| 47 | + |
| 48 | +<!-- |
| 49 | +## Example flow with endpoint termination |
| 50 | +
|
| 51 | +The following is the example of the flow described in the |
| 52 | +[Termination of Pods](/docs/concepts/workloads/pods/pod-lifecycle/#pod-termination) |
| 53 | +document. |
| 54 | +
|
| 55 | +Let's say you have a Deployment containing of a single `nginx` replica |
| 56 | +(just for demonstration purposes) and a Service: |
| 57 | +--> |
| 58 | +## 端点终止的示例流程 {#example-flow-with-endpoint-termination} |
| 59 | + |
| 60 | +以下是 [Pod 终止](/zh-cn/docs/concepts/workloads/pods/pod-lifecycle/#pod-termination)文档中所述的流程示例。 |
| 61 | + |
| 62 | +假设你有包含单个 nginx 副本(仅用于演示目的)的一个 Deployment 和一个 Service: |
| 63 | + |
| 64 | +{{< codenew file="service/pod-with-graceful-termination.yaml" >}} |
| 65 | + |
| 66 | +<!-- |
| 67 | +# extra long grace period |
| 68 | +# Real life termination may take any time up to terminationGracePeriodSeconds. |
| 69 | +# In this example - just hang around for at least the duration of terminationGracePeriodSeconds, |
| 70 | +# at 120 seconds container will be forcibly terminated. |
| 71 | +# Note, all this time nginx will keep processing requests. |
| 72 | +--> |
| 73 | +```yaml |
| 74 | +apiVersion: apps/v1 |
| 75 | +kind: Deployment |
| 76 | +metadata: |
| 77 | + name: nginx-deployment |
| 78 | + labels: |
| 79 | + app: nginx |
| 80 | +spec: |
| 81 | + replicas: 1 |
| 82 | + selector: |
| 83 | + matchLabels: |
| 84 | + app: nginx |
| 85 | + template: |
| 86 | + metadata: |
| 87 | + labels: |
| 88 | + app: nginx |
| 89 | + spec: |
| 90 | + terminationGracePeriodSeconds: 120 # 超长优雅期 |
| 91 | + containers: |
| 92 | + - name: nginx |
| 93 | + image: nginx:latest |
| 94 | + ports: |
| 95 | + - containerPort: 80 |
| 96 | + lifecycle: |
| 97 | + preStop: |
| 98 | + exec: |
| 99 | + # 实际生产环境中的 Pod 终止可能需要执行任何时长,但不会超过 terminationGracePeriodSeconds。 |
| 100 | + # 在本例中,只需挂起至少 terminationGracePeriodSeconds 所指定的持续时间, |
| 101 | + # 在 120 秒时容器将被强制终止。 |
| 102 | + # 请注意,在所有这些时间点 nginx 都将继续处理请求。 |
| 103 | + command: [ |
| 104 | + "/bin/sh", "-c", "sleep 180" |
| 105 | + ] |
| 106 | + |
| 107 | +--- |
| 108 | + |
| 109 | +apiVersion: v1 |
| 110 | +kind: Service |
| 111 | +metadata: |
| 112 | + name: nginx-service |
| 113 | +spec: |
| 114 | + selector: |
| 115 | + app: nginx |
| 116 | + ports: |
| 117 | + - protocol: TCP |
| 118 | + port: 80 |
| 119 | + targetPort: 80 |
| 120 | +``` |
| 121 | +
|
| 122 | +<!-- |
| 123 | +Once the Pod and Service are running, you can get the name of any associated EndpointSlices: |
| 124 | +--> |
| 125 | +一旦 Pod 和 Service 开始运行,你就可以获取对应的所有 EndpointSlices 的名称: |
| 126 | +
|
| 127 | +```shell |
| 128 | +kubectl get endpointslice |
| 129 | +``` |
| 130 | + |
| 131 | +<!-- |
| 132 | +The output is similar to this: |
| 133 | +--> |
| 134 | +输出类似于: |
| 135 | + |
| 136 | +```none |
| 137 | +NAME ADDRESSTYPE PORTS ENDPOINTS AGE |
| 138 | +nginx-service-6tjbr IPv4 80 10.12.1.199,10.12.1.201 22m |
| 139 | +``` |
| 140 | + |
| 141 | +<!-- |
| 142 | +You can see its status, and validate that there is one endpoint registered: |
| 143 | +--> |
| 144 | +你可以查看其 status 并验证已经有一个端点被注册: |
| 145 | + |
| 146 | +```shell |
| 147 | +kubectl get endpointslices -o json -l kubernetes.io/service-name=nginx-service |
| 148 | +``` |
| 149 | + |
| 150 | +<!-- |
| 151 | +The output is similar to this: |
| 152 | +--> |
| 153 | +输出类似于: |
| 154 | + |
| 155 | +```none |
| 156 | +{ |
| 157 | + "addressType": "IPv4", |
| 158 | + "apiVersion": "discovery.k8s.io/v1", |
| 159 | + "endpoints": [ |
| 160 | + { |
| 161 | + "addresses": [ |
| 162 | + "10.12.1.201" |
| 163 | + ], |
| 164 | + "conditions": { |
| 165 | + "ready": true, |
| 166 | + "serving": true, |
| 167 | + "terminating": false |
| 168 | + } |
| 169 | + } |
| 170 | + ] |
| 171 | +} |
| 172 | +``` |
| 173 | + |
| 174 | +<!-- |
| 175 | +Now let's terminate the Pod and validate that the Pod is being terminated |
| 176 | +respecting the graceful termination period configuration: |
| 177 | +--> |
| 178 | +现在让我们终止这个 Pod 并验证该 Pod 正在遵从体面终止期限的配置进行终止: |
| 179 | + |
| 180 | +```shell |
| 181 | +kubectl delete pod nginx-deployment-7768647bf9-b4b9s |
| 182 | +``` |
| 183 | + |
| 184 | +<!-- |
| 185 | +All pods: |
| 186 | +--> |
| 187 | +查看所有 Pod: |
| 188 | + |
| 189 | +```shell |
| 190 | +kubectl get pods |
| 191 | +``` |
| 192 | + |
| 193 | +<!-- |
| 194 | +The output is similar to this: |
| 195 | +--> |
| 196 | +输出类似于: |
| 197 | + |
| 198 | +```none |
| 199 | +NAME READY STATUS RESTARTS AGE |
| 200 | +nginx-deployment-7768647bf9-b4b9s 1/1 Terminating 0 4m1s |
| 201 | +nginx-deployment-7768647bf9-rkxlw 1/1 Running 0 8s |
| 202 | +``` |
| 203 | + |
| 204 | +<!-- |
| 205 | +You can see that the new pod got scheduled. |
| 206 | +
|
| 207 | +While the new endpoint is being created for the new Pod, the old endpoint is |
| 208 | +still around in the terminating state: |
| 209 | +--> |
| 210 | +你可以看到新的 Pod 已被调度。 |
| 211 | + |
| 212 | +当系统在为新的 Pod 创建新的端点时,旧的端点仍处于 Terminating 状态: |
| 213 | + |
| 214 | +```shell |
| 215 | +kubectl get endpointslice -o json nginx-service-6tjbr |
| 216 | +``` |
| 217 | + |
| 218 | +<!-- |
| 219 | +The output is similar to this: |
| 220 | +--> |
| 221 | +输出类似于: |
| 222 | + |
| 223 | +```none |
| 224 | +{ |
| 225 | + "addressType": "IPv4", |
| 226 | + "apiVersion": "discovery.k8s.io/v1", |
| 227 | + "endpoints": [ |
| 228 | + { |
| 229 | + "addresses": [ |
| 230 | + "10.12.1.201" |
| 231 | + ], |
| 232 | + "conditions": { |
| 233 | + "ready": false, |
| 234 | + "serving": true, |
| 235 | + "terminating": true |
| 236 | + }, |
| 237 | + "nodeName": "gke-main-default-pool-dca1511c-d17b", |
| 238 | + "targetRef": { |
| 239 | + "kind": "Pod", |
| 240 | + "name": "nginx-deployment-7768647bf9-b4b9s", |
| 241 | + "namespace": "default", |
| 242 | + "uid": "66fa831c-7eb2-407f-bd2c-f96dfe841478" |
| 243 | + }, |
| 244 | + "zone": "us-central1-c" |
| 245 | + }, |
| 246 | + ] |
| 247 | + { |
| 248 | + "addresses": [ |
| 249 | + "10.12.1.202" |
| 250 | + ], |
| 251 | + "conditions": { |
| 252 | + "ready": true, |
| 253 | + "serving": true, |
| 254 | + "terminating": false |
| 255 | + }, |
| 256 | + "nodeName": "gke-main-default-pool-dca1511c-d17b", |
| 257 | + "targetRef": { |
| 258 | + "kind": "Pod", |
| 259 | + "name": "nginx-deployment-7768647bf9-rkxlw", |
| 260 | + "namespace": "default", |
| 261 | + "uid": "722b1cbe-dcd7-4ed4-8928-4a4d0e2bbe35" |
| 262 | + }, |
| 263 | + "zone": "us-central1-c" |
| 264 | + } |
| 265 | +} |
| 266 | +``` |
| 267 | + |
| 268 | +<!-- |
| 269 | +This allows applications to communicate their state during termination |
| 270 | +and clients (such as load balancers) to implement a connections draining functionality. |
| 271 | +These clients may detect terminating endpoints and implement a special logic for them. |
| 272 | +--> |
| 273 | +这种设计使得应用可以在终止期间公布自己的状态,而客户端(如负载均衡器)则可以实现连接排空功能。 |
| 274 | +这些客户端可以检测到正在终止的端点,并为这些端点实现特殊的逻辑。 |
| 275 | + |
| 276 | +<!-- |
| 277 | +In Kubernetes, endpoints that are terminating always have their `ready` status set as as `false`. |
| 278 | +This needs to happen for backward |
| 279 | +compatibility, so existing load balancers will not use it for regular traffic. |
| 280 | +If traffic draining on terminating pod is needed, the actual readiness can be |
| 281 | +checked as a condition `serving`. |
| 282 | +
|
| 283 | +When Pod is deleted, the old endpoint will also be deleted. |
| 284 | +--> |
| 285 | +在 Kubernetes 中,正在终止的端点始终将其 `ready` 状态设置为 `false`。 |
| 286 | +这是为了满足向后兼容的需求,确保现有的负载均衡器不会将 Pod 用于常规流量。 |
| 287 | +如果需要排空正被终止的 Pod 上的流量,可以将 `serving` 状况作为实际的就绪状态。 |
| 288 | + |
| 289 | +当 Pod 被删除时,旧的端点也会被删除。 |
| 290 | + |
| 291 | +## {{% heading "whatsnext" %}} |
| 292 | + |
| 293 | +<!-- |
| 294 | +* Learn how to [Connect Applications with Services](/docs/tutorials/services/connect-applications-service/) |
| 295 | +* Learn more about [Using a Service to Access an Application in a Cluster](/docs/tasks/access-application-cluster/service-access-application-cluster/) |
| 296 | +* Learn more about [Connecting a Front End to a Back End Using a Service](/docs/tasks/access-application-cluster/connecting-frontend-backend/) |
| 297 | +* Learn more about [Creating an External Load Balancer](/docs/tasks/access-application-cluster/create-external-load-balancer/) |
| 298 | +--> |
| 299 | +* 了解如何[使用 Service 连接到应用](/zh-cn/docs/tutorials/services/connect-applications-service/) |
| 300 | +* 进一步了解[使用 Service 访问集群中的应用](/zh-cn/docs/tasks/access-application-cluster/service-access-application-cluster/) |
| 301 | +* 进一步了解[使用 Service 把前端连接到后端](/zh-cn/docs/tasks/access-application-cluster/connecting-frontend-backend/) |
| 302 | +* 进一步了解[创建外部负载均衡器](/zh-cn/docs/tasks/access-application-cluster/create-external-load-balancer/) |
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