弹性扩展

目的

测试 OpenSHift 水平弹性扩展，资源限制。

环境

• openshift v3.11.16/kubernetes v1.11.0

步骤

创建工程

$ oc login https://master.example.com:8443 -u admin -p admin

$ oc new-project test-hpa

准备测试镜像

本部分使用测试镜像是：https://hub.docker.com/r/openshift/hello-openshift[openshift/hello-openshift]，使用如下命名下载镜像，并打 tag.

# docker pull openshift/hello-openshift
# docker tag docker.io/openshift/hello-openshift:latest registry.example.com/openshift/hello-openshift:latest
# docker push registry.example.com/openshift/hello-openshift:latest

创建应用

# oc new-app registry.example.com/openshift/hello-openshift:latest -n test-hpa
# oc expose svc hello-openshift

创建 LimitRange

创建 LimitRange，限制

• Pod 最小 CPU: 10m

• Pod 最大 CPU: 100m

• Pod 最小内存: 5Mi

• Pod 最大内存: 750Mi

• Container 最小 CPU: 10m

• Container 最大 CPU: 100m

• Container 最小内存: 5Mi

• Container 最大内存: 750Mi

• Container 默认 CPU: 50m

• Container 默认内存: 100Mi

echo '{
    "kind": "LimitRange",
    "apiVersion": "v1",
    "metadata": {
        "name": "limits",
        "creationTimestamp": null
    },
    "spec": {
        "limits": [
            {
                "type": "Pod",
                "max": {
                    "cpu": "100m",
                    "memory": "750Mi"
                },
                "min": {
                    "cpu": "10m",
                    "memory": "5Mi"
                }
            },
            {
                "type": "Container",
                "max": {
                    "cpu": "100m",
                    "memory": "750Mi"
                },
                "min": {
                    "cpu": "10m",
                    "memory": "5Mi"
                },
                "default": {
                    "cpu": "50m",
                    "memory": "100Mi"
                }
            }
        ]
    }
}' | oc create -f - -n test-hpa

# oc get limitrange
NAME      CREATED AT
limits    2019-02-24T20:06:08Z

创建 HPA

# oc autoscale dc/hello-openshift --min 1 --max 5 --cpu-percent=80

# oc get hpa hello-openshift
NAME              REFERENCE                          TARGETS         MINPODS   MAXPODS   REPLICAS   AGE
hello-openshift   DeploymentConfig/hello-openshift   <unknown>/80%   1         5         1          55s

测试弹性扩展

# oc rollout latest hello-openshift -n test-hpa

# for time in {1..15000}; do curl http://hello-openshift-test-hpa.apps.example.com; done

# oc get pods
NAME                      READY     STATUS    RESTARTS   AGE
hello-openshift-2-p8vt5   1/1       Running   0          3m
hello-openshift-2-whwg9   1/1       Running   0          9m