文章目录

  1. ​​Red Hat OpenShift 4.8 环境集群搭建​​
  2. ​​openshift 如何输出json日志​​
  3. ​​openshfit Vertical Pod Autoscaler 实践​​
  4. ​​openshift Certified Helm Charts 实践​​
  5. ​​openshift 创建一个Serverless应用程序​​
  6. ​​openshift gitops 实践​​
  7. ​​openshift Tekton pipeline 实践​​

1. Serverless Lab

使用​​Knative Serverless​​​，您可以轻松地在Kubernetes上运行无服务器容器。Knative负责网络、自动伸缩(甚至为零)和修订跟踪的细节。这让你能够专注于你的核心逻辑。
在本实验室中，您将学习如何将无服务器应用程序部署为“服务”应用程序。

Serverless服务
减少资源消耗的一种好方法是确定哪些服务需要24/7运行。示例咖啡店应用程序有三个组件: a database, a front-end coffee shop, and a service barista that makes drinks。似乎只有在咖啡订单实际提交时才需要咖啡师服务，而咖啡店前端应该始终运行。因此，有必要将咖啡师服务转换为无服务器服务，在不使用时可以扩展到零副本。

目标：

  • 将咖啡师应用程序转换为无服务器服务
  • 观察日志的变化

2. 将Barista应用程序转换为无服务器服务

咖啡师应用程序不需要一直运行。它只需要在创建新订单时运行。因此，当咖啡店没有流量时，应用程序不需要消耗资源。

2.1 Delete Barista Deployment and Service

  1. Go to your Red Hat® OpenShift® Container Platform web console and log in as​​admin​​.
  2. Use the perspective switcher to switch to the​​Developer​​ perspective.
  3. If a pop-up window appears, click​​Cancel​​.
  4. In the navigation menu, click​​Topology.​​

A graphical representation of your application appears, displaying the app components, plus a cron job that orders drinks every minute:
openshift 创建一个Serverless应用程序_kubernetes

  1. Click​​D barista​​ to display the details panel.
  2. You need to delete this barista OpenShift service and the baristadeployment before you can deploy a Knative service by the same name.
  3. Click​​S barista​​ to open the Service details page.
  4. Select​​Actions → Delete​​ Service and confirm.
  5. Go back to​​Topology​​​ and click​​D barista​​ again to verify that the service was deleted.
  6. Select​​Actions → Delete deployment​​​ to delete the​​barista​​ deployment.

Confirm the deletion.

2.2 Deploy Barista Component as Knative Service

在本节中，您将把咖啡师容器映像部署为Knative无服务器服务。Knative服务的API包不同于Kubernetes服务，扮演着不同的角色。

Kubernetes Service service.k8s.io/v1: Service is a named abstraction of software service (for example, mysql) consisting of a local port (for example 3306) that the proxy listens on, and the selector that determines which pods will answer requests sent through the proxy. ​​https://kubernetes.io/docs/reference/kubernetes-api/service-resources/service-v1/​​

Knative Service serving.knative.dev/v1: A complete application: ​​https://knative.dev/docs/reference/api/serving-api/#serving.knative.dev​​

  1. On the navigation menu, click​​Add​​.
  2. Click​​Container Images​​.
  3. Fill in the​​Image stream from internal registry​​​ fields as follows:
    Project:​​​dev-coffeeshop​​​ Image Stream: ​​barista​​ Tag: ​​latest​​
  4. Complete the remaining fields as follows:
    ​​​Runtime icon​​​: select the Knative icon
    ​​​Application​​​: coffee-shop
    ​​​Name​​​: barista
    ​​​Resources​​​: select the Knative Service radio button
    ​​​Create a route to the Applicatio​​n: check this box
  5. Click​​Create​​​ Expect the ​​Topology​​ view to appear with the new KSVC barista service along with its revision number.

3 更新咖啡店ConfigMap访问Knative咖啡师服务

The route to the barista part of the application has changed, so the coffee shop component cannot find it.

The old service URL was ​​http://barista:8080/processes​​​. The new service URL (Knative route) is ​​http://barista.dev-coffeeshop.svc.cluster.local/processes​​. Knative使用项目名而不是服务名，并且端口现在由Knative处理。这将断开咖啡店应用程序和咖啡师应用程序之间的连接。

In this exercise, you reconnect them.

3.1 Fix ConfigMap that Associates ​​coffee-shop​​​ and ​​barista​​

The ​​coffee-shop​​​ application gets its ​​BARISTA_URL​​ from a ConfigMap.

  1. In the navigation menu, click​​ConfigMaps​​​ and then click​​CM coffee-shop​​.
  2. Scroll down to the​​Data​​​ section and the​​BARISTA_URL​​​ of​​http://barista:8080/processes​​.
  3. Select​​Actions → Edit ConfigMap​​.
  4. In the YAML listing that opens, copy and paste the following URL into the​​BARISTA_URL​​​ value:
    ​​​http://barista.dev-coffeeshop.svc.cluster.local/processes​​.

3.2 Restart coffee-shop Application

在本节中，您将向下扩展咖啡店部署并备份以获取ConfigMap更改。

  1. Return to Topology and click​​D coffee-shop​​.
  2. In the panel that appears, click the​​Details​​​ tab.
    Expect to see three running pods.
    3.使用箭头按钮来缩小到0，然后返回到3

3.3 Access coffee-shop Web Application

要确保​​coffee-shop​​​应用程序工作，请在coffee-shop应用程序上单击Open URL，而不是​​barista​​​应用程序:
openshift 创建一个Serverless应用程序_openshift_02
预计会出现一两行JSON输出。

  1. Add​​/index.html​​ to the end of the URL to access the application.

如果看到类似​​RESTEASY003210​​​的错误…你走的是Knative ​​barista​​​的路线。这是错误的路线。使用​​coffee-shop​​路线代替。

  1. 点一杯饮料，并验证咖啡师应用程序可以扩展到处理请求

Expect to see some beverages already ordered by the order-drinks cron job. Your order is at the bottom of the list.

The ​​order-drinks​​​ cron job orders two new drinks every minute from the ​​coffee-shop​​​ application in the ​​dev-coffeeshop​​ namespace.

4 Examine Logs

如果您返回Kibana接口，您会看到结构化类型中现在有更多的字段。它们大多是当您从Kubernetes部署更改为Knative应用程序时，应用程序捕获的应用程序异常。

  1. 返回Kibana web界面，从左侧导航面板单击Discovery。
  2. 从“可用字段”一节中，将​​*t* structured.error.message​​添加到日志发现中。
  3. 使用顶部的时间滑块来关注带有错误消息的事件。
    希望很容易找到错误消息，例如​​​“RESTEASY004655​​​: Unable to invoke r .”
    java.net.NoRouteToHostException: No route to host (Host unreachable)".

您使用Knative将一个无服务器应用程序部署为一个服务应用程序。
现在，在下一个模块中，我们将继续学习GitOps。使用GitOps，您可以将咖啡馆应用程序的部署自动化到生产环境，所有这些都来自一个Git存储库。