OpenShift 4.3 之Knative-Tutorial(1) 创建Serverless运行环境
文章目录
- 说明
- 客户端环境
- 配置Knative环境
- 通过OpenShift Console实现
- 安装OpenShift Serverless Operator
- 创建Knative Serving应用运行环境
- 创建Knative Serving应用运行环境
- 通过脚本实现
- 部署并测试Hello的Serverless应用
说明
OpenShift Serverless Operator为无服务器应用提供提供了Knative Serving的运行环境。需要以下两步就可以在OpenShift上运行Knative应用：安装所需的Operator和配置Knative Serving运行环境。
客户端环境
从以下地址下载对应环境的OpenShift Client和Knative Client，然后将oc和kn配置到PATH中。
- https://mirror.openshift.com/pub/openshift-v4/clients/oc/4.3/
- https://mirror.openshift.com/pub/openshift-v4/clients/serverless/latest/
配置Knative环境
我们可以用OpenShift控制台或OpenShift命令行创建Knative及其所需的运行环境。下面分别介绍这两种方法。
通过OpenShift Console实现
安装OpenShift Serverless Operator
注意：通过OpenShift Console安装OpenShift Serverless Operator时候，OpenShift会自动安装OpenShift Serverless Operator所依赖的Service Mesh Opeator，因此Operator的安装过程非常简单。
- 用集群管理员登录OpenShift Console。
- 在Administrator视图中进入Operators->OperatorHub，然后找到“OpenShift Serverless Operator”，点击进入，最后在右滑窗口中接受所有缺省配置一直到完成即可。
- 完后上一步后，可以在控制台中进入任意一个项目（例如default项目），可以在Operators->Installed Operators中看到以下Operators。此时就完成了OpenShift Serverless Operator安装。
创建Knative Serving应用运行环境
Knative Serving提供了Serverless应用的支撑运行环境。Knative Serving必须运行在knative-serving项目中。
- 创建knative-serving项目。
$ oc new-project knative-serving
- 切换到knative-serving项目，再次进入Operators->Installed Operators，然后进入OpenShift Serverless Operator的配置。
- 在Overview页面中点击Knative Serving区域的Create Instance链接。
- 在Create KnativeServing界面中接受缺省配置，然后点击Create。
- 然后进入名为knative-serving的KnativeServing配置。需要等一段时间，直到下图中4个状态全部为True，此时就成功创建了Knative Serving环境。
- 可以切换到knative-serving项目的Developer视图，可以以下6个Deployment。
创建Knative Serving应用运行环境
- 创建knative-serving.yaml文件，内容为以下部分：
apiVersion: v1
kind: Namespace
metadata:
name: knative-serving
---
apiVersion: operator.knative.dev/v1alpha1
kind: KnativeServing
metadata:
name: knative-serving
namespace: knative-serving
- 执行命令创建项目和KnativeServing资源
$oc apply -f knative-serving.yaml
- 查看knative-serving的状态，成功完成后显示以下内容。
$ oc get knativeserving.operator.knative.dev/knative-serving -n knative-serving --template='{{range .status.conditions}}{{printf "%s =%s\n" .type .status}}{{end}}'
DependenciesInstalled=True
DeploymentsAvailable=True
InstallSucceeded=True
Ready=True
通过脚本实现
使用脚本创建Serverless环境参见《OpenShift 4.3 通过脚本配置ServiceMesh和Serverless运行环境》。
部署并测试Hello的Serverless应用
- 创建knative-demo项目。
$ oc new-project knative-demo
- 部署Knative的Hello应用。其中“–env TARGET=Knative”是将字符串传给TARGET环境变量。
$ kn service create hello --image gcr.io/knative-samples/helloworld-go --env TARGET=Knative
Creating service 'hello' in namespace 'knative-demo':
0.296s The Route is still working to reflect the latest desired specification.
0.393s Configuration "hello" is waiting for a Revision to become ready.
33.138s ...
33.369s Ingress has not yet been reconciled.
33.466s Configuration "hello" is waiting for a Revision to become ready.
33.543s Ingress has not yet been reconciled.
74.629s Ready to serve.
Service 'hello' created with latest revision 'hello-nvhqs-1' and URL:
http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com
- 查看Knative的Service列表。
$ kn service list
NAME URL LATEST AGE CONDITIONS READY REASON
hello http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com hello-nvhqs-1 2m4s 3 OK / 3 True
- 查看knative-demo项目中的所有资源，其中包括Knative的configuration、service、revision、route对象，还有OpenShift的service、deployment、rs对象。注意：当前项目中还没有pod资源。
$ oc get all -n knative-demo
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/hello ExternalName <none> cluster-local-gateway.knative-serving-ingress.svc.cluster.local <none> 10m
service/hello-nvhqs-1 ClusterIP 172.30.69.130 <none> 80/TCP 10m
service/hello-nvhqs-1-private ClusterIP 172.30.125.146 <none> 80/TCP,9090/TCP,9091/TCP,8022/TCP 10m
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/hello-nvhqs-1-deployment 0/0 0 0 10m
NAME DESIRED CURRENT READY AGE
replicaset.apps/hello-nvhqs-1-deployment-66db57b95f 0 0 0 10m
NAME CONFIG NAME K8S SERVICE NAME GENERATION READY REASON
revision.serving.knative.dev/hello-nvhqs-1 hello hello-nvhqs-1 1 True
NAME LATESTCREATED LATESTREADY READY REASON
configuration.serving.knative.dev/hello hello-nvhqs-1 hello-nvhqs-1 True
NAME URL READY REASON
route.serving.knative.dev/hello http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com True
NAME URL LATESTCREATED LATESTREADY READY REASON
service.serving.knative.dev/hello http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com hello-nvhqs-1 hello-nvhqs-1 True
- 在OpenShift Console中进入knative-demo的Developer视图，可以看到和hello应用相关的资源。
- 访问hello应用的地址，确认可以返回“Hello Knative!”，其中“Knative”为传进去的环境变量。
$ curl http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com
Hello Knative!
- 此时立即执行以下命令，确认此时可以查看项目在运行的Pod资源。不过在一分钟以后会又看不到Pod了。
$ oc get pod
NAME READY STATUS RESTARTS AGE
pod/hello-rfgt4-1-deployment-a0cd0125-cfvny 2/2 Running 0 22s
- 更新名为hello的service的环境变量内容。
$ kn service update hello --env TARGET=Kn
Updating Service 'hello' in namespace 'knative-demo':
10.760s Traffic is not yet migrated to the latest revision.
10.871s Ingress has not yet been reconciled.
12.231s Ready to serve.
Service 'hello' updated with latest revision 'hello-cfvny-2' and URL:
http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com
- 访问hello应用的地址，确认可以返回结果已经变化。
$ curl http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com
Hello Kn!
- 查看项目所有资源，确认OpenShift的deployment、rs对象和Knative的revision对象都已经有了一个新版的配置。
$ oc get all
NAME READY STATUS RESTARTS AGE
pod/hello-cfvny-2-deployment-d4cd7655-rfgt4 2/2 Running 0 22s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/hello ExternalName <none> cluster-local-gateway.knative-serving-ingress.svc.cluster.local <none> 5h6m
service/hello-cfvny-2 ClusterIP 172.30.69.131 <none> 80/TCP 6m22s
service/hello-cfvny-2-private ClusterIP 172.30.64.141 <none> 80/TCP,9090/TCP,9091/TCP,8022/TCP 6m22s
service/hello-nvhqs-1 ClusterIP 172.30.69.130 <none> 80/TCP 5h6m
service/hello-nvhqs-1-private ClusterIP 172.30.125.146 <none> 80/TCP,9090/TCP,9091/TCP,8022/TCP 5h6m
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/hello-cfvny-2-deployment 1/1 1 1 6m22s
deployment.apps/hello-nvhqs-1-deployment 0/0 0 0 5h6m
NAME DESIRED CURRENT READY AGE
replicaset.apps/hello-cfvny-2-deployment-d4cd7655 1 1 1 6m22s
replicaset.apps/hello-nvhqs-1-deployment-66db57b95f 0 0 0 5h6m
NAME LATESTCREATED LATESTREADY READY REASON
configuration.serving.knative.dev/hello hello-cfvny-2 hello-cfvny-2 True
NAME CONFIG NAME K8S SERVICE NAME GENERATION READY REASON
revision.serving.knative.dev/hello-cfvny-2 hello hello-cfvny-2 2 True
revision.serving.knative.dev/hello-nvhqs-1 hello hello-nvhqs-1 1 True
NAME URL LATESTCREATED LATESTREADY READY REASON
service.serving.knative.dev/hello http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com hello-cfvny-2 hello-cfvny-2 True
NAME URL READY REASON
route.serving.knative.dev/hello http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com True
- 查看名为hello的service详细信息。确认最新的revision（hello-cfvny-2）接收了100%的请求。
$ kn service describe hello
Name: hello
Namespace: knative-demo
Age: 5h
URL: http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com
Revisions:
100% @latest (hello-cfvny-2) [2] (2m)
Image: gcr.io/knative-samples/helloworld-go (pinned to 5ea96b)
Conditions:
OK TYPE AGE REASON
++ Ready 2m
++ ConfigurationsReady 2m
++ RoutesReady 2m
- 查看Knative的revision对象。确认结果和（10）看到的项目包括的revision一样。
$ kn revision list
NAME SERVICE GENERATION AGE CONDITIONS READY REASON
hello-cfvny-2 hello 2 45m 3 OK / 4 True
hello-nvhqs-1 hello 1 5h46m 3 OK / 4 True
- 执行命令，将请求平均发给以上2个revision。
$ kn service update hello --traffic @latest=50 --traffic hello-nvhqs-1=50
Updating Service 'hello' in namespace 'knative-demo':
0.066s The Route is still working to reflect the latest desired specification.
0.090s Ingress has not yet been reconciled.
1.450s Ready to serve.
Service 'hello' updated with latest revision 'hello-cfvny-2' (unchanged) and URL:
http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com
- 查看Knative的service对象，确认配置修改为2个revision各自接收50%的请求。
$ kn service describe hello
Name: hello
Namespace: knative-demo
Age: 5h
URL: http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com
Revisions:
50% @latest (hello-cfvny-2) [2] (41m)
Image: gcr.io/knative-samples/helloworld-go (pinned to 5ea96b)
50% hello-nvhqs-1 [1] (5h)
Image: gcr.io/knative-samples/helloworld-go (pinned to 5ea96b)
Conditions:
OK TYPE AGE REASON
++ Ready 6m
++ ConfigurationsReady 41m
++ RoutesReady 6m
- 在OpenShift控制台的Developer视图中可以上可以看到hello应用的Toplogy。
- 点击上图的Set Traffic Distribution按钮，可以在弹出窗口中可以为不同的Revision分配流量比例。
- 多次访问hello应用，确认返回结果部分是“Hello Knative!”、部分是“Hello Kn!”。
$ curl http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com
Hello Knative!
$ curl http://hello.knative-demo.apps.cluster-shanghai-3d3e.shanghai-3d3e.example.opentlc.com
Hello Kn!