From 7eeb6031540106abb6c74667fb8a5bb1870a8f18 Mon Sep 17 00:00:00 2001 From: jianglingxia Date: Fri, 15 Sep 2017 07:17:17 +0800 Subject: [PATCH] =?UTF-8?q?ZTE-SH-CN-run-application-run-single-instance-s?= =?UTF-8?q?tateful-application-pr-2017-=E2=80=A6=20(#5363)?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit * zte-run-application-run-single-instance-stateful-application-pr-2017-09-09 * ZTE-SH-CN-run-application-run-single-instance-stateful-application-pr-2017-09-12 * ZTE-SH-CN-run-application-run-single-instance-stateful-application-pr-2017-09-13 * ZTE-SH-CN-run-application-run-single-instance-stateful-application-pr-2017-09-14 --- ...un-single-instance-stateful-application.md | 226 ++++++++++++++++++ 1 file changed, 226 insertions(+) create mode 100644 cn/docs/tasks/run-application/run-single-instance-stateful-application.md diff --git a/cn/docs/tasks/run-application/run-single-instance-stateful-application.md b/cn/docs/tasks/run-application/run-single-instance-stateful-application.md new file mode 100644 index 0000000000..02ae15dc86 --- /dev/null +++ b/cn/docs/tasks/run-application/run-single-instance-stateful-application.md @@ -0,0 +1,226 @@ +--- +title: 运行一个单实例有状态应用 +--- + +{% capture overview %} + +本文介绍在Kubernetes中使用PersistentVolume和Deployment如何运行一个单实例有状态应用. 该应用是MySQL. + +{% endcapture %} + + +{% capture objectives %} + +* 在环境中通过磁盘创建一个PersistentVolume. +* 创建一个MySQL Deployment. +* 在集群内以一个已知的DNS名将MySQL暴露给其他pods. + +{% endcapture %} + + +{% capture prerequisites %} + +* {% include task-tutorial-prereqs.md %} + +* 为了数据持久性我们将在环境上通过磁盘创建一个持久卷. 环境支持的类型见这里[here](/docs/user-guide/persistent-volumes/#types-of-persistent-volumes). 本篇文档将介绍 `GCEPersistentDisk` . `GCEPersistentDisk`卷只能工作在Google Compute Engine平台上. + +{% endcapture %} + + +{% capture lessoncontent %} + +## 在环境中设置一个磁盘 + +你可以为有状态的应用使用任何类型的持久卷. 有关支持环境的磁盘列表，请参考持久卷类型[Types of Persistent Volumes](/docs/user-guide/persistent-volumes/#types-of-persistent-volumes). 对于Google Compute Engine, 请运行: + +``` +gcloud compute disks create --size=20GB mysql-disk +``` + + +接下来创建一个指向刚创建的 `mysql-disk`磁盘的PersistentVolume. 下面是一个PersistentVolume的配置文件，它指向上面创建的Compute Engine磁盘: + +{% include code.html language="yaml" file="gce-volume.yaml" ghlink="/docs/tasks/run-application/gce-volume.yaml" %} + +注意`pdName: mysql-disk` 这行与Compute Engine环境中的磁盘名称相匹配. 有关为其 +他环境编写PersistentVolume配置文件的详细信息，请参见持久卷[Persistent Volumes](/docs/concepts/storage/persistent-volumes/). + + +创建持久卷: + +``` +kubectl create -f https://k8s.io/docs/tasks/run-application/gce-volume.yaml +``` + + + +## 部署MySQL + +通过创建Kubernetes Deployment并使用PersistentVolumeClaim将其连接到现已存在的PersistentVolume上来运行一个有状态的应用. 例如, 下面这个YAML文件描述了一个运行MySQL +并引用PersistentVolumeClaim的Deployment. 该文件定义了一个volume其挂载目录为/var/lib/mysql, 然后创建一个内存为20G的卷的PersistentVolumeClaim. 此申领可以通过任 +何符合需求的卷来满足, 在本例中满足上面创建的卷. + + +注意: 在配置的yaml文件中定义密码的做法是不安全的. 具体安全解决方案请参考 +[Kubernetes Secrets](/docs/concepts/configuration/secret/). + +{% include code.html language="yaml" file="mysql-deployment.yaml" ghlink="/docs/tasks/run-application/mysql-deployment.yaml" %} + + +1. 部署YAML文件中定义的内容: + + kubectl create -f https://k8s.io/docs/tasks/run-application/mysql-deployment.yaml + + +1. 展示Deployment相关信息: + + kubectl describe deployment mysql + + Name: mysql + Namespace: default + CreationTimestamp: Tue, 01 Nov 2016 11:18:45 -0700 + Labels: app=mysql + Annotations: deployment.kubernetes.io/revision=1 + Selector: app=mysql + Replicas: 1 desired | 1 updated | 1 total | 0 available | 1 unavailable + StrategyType: Recreate + MinReadySeconds: 0 + Pod Template: + Labels: app=mysql + Containers: + mysql: + Image: mysql:5.6 + Port: 3306/TCP + Environment: + MYSQL_ROOT_PASSWORD: password + Mounts: + /var/lib/mysql from mysql-persistent-storage (rw) + Volumes: + mysql-persistent-storage: + Type: PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace) + ClaimName: mysql-pv-claim + ReadOnly: false + Conditions: + Type Status Reason + ---- ------ ------ + Available False MinimumReplicasUnavailable + Progressing True ReplicaSetUpdated + OldReplicaSets: + NewReplicaSet: mysql-63082529 (1/1 replicas created) + Events: + FirstSeen LastSeen Count From SubobjectPath Type Reason Message + --------- -------- ----- ---- ------------- -------- ------ ------- + 33s 33s 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set mysql-63082529 to 1 + + +1. 列举出Deployment创建的pods: + + kubectl get pods -l app=mysql + + NAME READY STATUS RESTARTS AGE + mysql-63082529-2z3ki 1/1 Running 0 3m + + +1. 查看持久卷: + + kubectl describe pv mysql-pv + + Name: mysql-pv + Labels: + Status: Bound + Claim: default/mysql-pv-claim + Reclaim Policy: Retain + Access Modes: RWO + Capacity: 20Gi + Message: + Source: + Type: GCEPersistentDisk (a Persistent Disk resource in Google Compute Engine) + PDName: mysql-disk + FSType: ext4 + Partition: 0 + ReadOnly: false + No events. + + +1. 查看PersistentVolumeClaim: + + kubectl describe pvc mysql-pv-claim + + Name: mysql-pv-claim + Namespace: default + Status: Bound + Volume: mysql-pv + Labels: + Capacity: 20Gi + Access Modes: RWO + No events. + + +## 访问MySQL实例 + + +前面YAML文件中创建了一个允许集群内其他pods访问数据库的服务. 该服务中选项 +`clusterIP: None` 让服务DNS名称直接解析为Pod的IP地址. 当在一个服务下只有一个pod +并且不打算增加pods的数量这是最好的. + + +运行MySQL客户端以连接到服务器: + +``` +kubectl run -it --rm --image=mysql:5.6 mysql-client -- mysql -h -p +``` + +此命令在集群内创建一个新的Pod并运行MySQL客户端,并通过服务将其连接到服务器.如果连接成功,你就知道有状态的MySQL database正处于运行状态. + +``` +Waiting for pod default/mysql-client-274442439-zyp6i to be running, status is Pending, pod ready: false +If you don't see a command prompt, try pressing enter. + +mysql> +``` + +## 更新 + + +Deployment中镜像或其他部分同往常一样可以通过 `kubectl apply` 命令更新. 以下是 +特定于有状态应用的一些注意事项: + +* 不要弹性伸缩. 弹性伸缩仅适用于单实例应用. 下层的PersistentVolume仅只能挂载一个pod. 对于集群级有状态应用, 请参考StatefulSet文档 + [StatefulSet documentation](/docs/concepts/workloads/controllers/statefulset/). +* 在Deployment的YAML文件中使用 `strategy:` `type: Recreate` . 该选项指示Kubernetes不使用滚动升级. 滚动升级将无法工作, 由于一次不能运行多个pod. 在更新配置文件 +创建一个新的pod前 `Recreate`策略将先停止第一个pod. + + +## 删除deployment + + +通过名称删除部署的对象: + +``` +kubectl delete deployment,svc mysql +kubectl delete pvc mysql-pv-claim +kubectl delete pv mysql-pv +``` + +如果使用Compute Engine磁盘，也可以使用如下命令: + +``` +gcloud compute disks delete mysql-disk +``` + +{% endcapture %} + + +{% capture whatsnext %} + +* 了解更多Deployment对象请参考 [Deployment objects](/docs/concepts/workloads/controllers/deployment/). + +* 了解更多Deployment应用请参考 [Deploying applications](/docs/user-guide/deploying-applications/) + +* kubectl run文档请参考[kubectl run documentation](/docs/user-guide/kubectl/v1.6/#run) + +* 卷和持久卷请参考[Volumes](/docs/concepts/storage/volumes/) and [Persistent Volumes](/docs/concepts/storage/persistent-volumes/) + +{% endcapture %} + +{% include templates/tutorial.md %}