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7.2.3. 以 pod 中作业的方式运行集群容量工具

7.2.3. 以 pod 中作业的方式运行集群容量工具

若以 pod 中作业的方式运行集群容量工具，其优点是可以在无需用户干预的前提下多次运行。以作业方式运行集群容量工具涉及使用 ConfigMap 对象。

先决条件

流程

运行集群容量工具：

创建集群角色：

cat << EOF| oc create -f -

$ cat << EOF| oc create -f -

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输出示例

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: cluster-capacity-role
rules:
- apiGroups: [""]
  resources: ["pods", "nodes", "persistentvolumeclaims", "persistentvolumes", "services", "replicationcontrollers"]
  verbs: ["get", "watch", "list"]
- apiGroups: ["apps"]
  resources: ["replicasets", "statefulsets"]
  verbs: ["get", "watch", "list"]
- apiGroups: ["policy"]
  resources: ["poddisruptionbudgets"]
  verbs: ["get", "watch", "list"]
- apiGroups: ["storage.k8s.io"]
  resources: ["storageclasses"]
  verbs: ["get", "watch", "list"]
EOF

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: cluster-capacity-role
rules:
- apiGroups: [""]
  resources: ["pods", "nodes", "persistentvolumeclaims", "persistentvolumes", "services", "replicationcontrollers"]
  verbs: ["get", "watch", "list"]
- apiGroups: ["apps"]
  resources: ["replicasets", "statefulsets"]
  verbs: ["get", "watch", "list"]
- apiGroups: ["policy"]
  resources: ["poddisruptionbudgets"]
  verbs: ["get", "watch", "list"]
- apiGroups: ["storage.k8s.io"]
  resources: ["storageclasses"]
  verbs: ["get", "watch", "list"]
EOF

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创建服务帐户：
```
oc create sa cluster-capacity-sa
```
```
$ oc create sa cluster-capacity-sa
```
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将角色添加到服务帐户：

oc adm policy add-cluster-role-to-user cluster-capacity-role \
    system:serviceaccount:default:cluster-capacity-sa

$ oc adm policy add-cluster-role-to-user cluster-capacity-role \
    system:serviceaccount:default:cluster-capacity-sa

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定义并创建 Pod 规格：

apiVersion: v1
kind: Pod
metadata:
  name: small-pod
  labels:
    app: guestbook
    tier: frontend
spec:
  containers:
  - name: php-redis
    image: gcr.io/google-samples/gb-frontend:v4
    imagePullPolicy: Always
    resources:
      limits:
        cpu: 150m
        memory: 100Mi
      requests:
        cpu: 150m
        memory: 100Mi

apiVersion: v1
kind: Pod
metadata:
  name: small-pod
  labels:
    app: guestbook
    tier: frontend
spec:
  containers:
  - name: php-redis
    image: gcr.io/google-samples/gb-frontend:v4
    imagePullPolicy: Always
    resources:
      limits:
        cpu: 150m
        memory: 100Mi
      requests:
        cpu: 150m
        memory: 100Mi

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集群容量分析使用名为 cluster-capacity-configmap 的 ConfigMap 对象挂载到卷中，从而将输入 pod 规格文件 pod.yaml 挂载到卷 test-volume 的路径 /test-pod 上。
如果还没有创建 ConfigMap 对象，请在创建作业前创建：
```
oc create configmap cluster-capacity-configmap \
    --from-file=pod.yaml=pod.yaml
```
```
$ oc create configmap cluster-capacity-configmap \
    --from-file=pod.yaml=pod.yaml
```
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使用以下作业规格文件示例创建作业：

apiVersion: batch/v1
kind: Job
metadata:
  name: cluster-capacity-job
spec:
  parallelism: 1
  completions: 1
  template:
    metadata:
      name: cluster-capacity-pod
    spec:
        containers:
        - name: cluster-capacity
          image: openshift/origin-cluster-capacity
          imagePullPolicy: "Always"
          volumeMounts:
          - mountPath: /test-pod
            name: test-volume
          env:
          - name: CC_INCLUSTER 
            value: "true"
          command:
          - "/bin/sh"
          - "-ec"
          - |
            /bin/cluster-capacity --podspec=/test-pod/pod.yaml --verbose
        restartPolicy: "Never"
        serviceAccountName: cluster-capacity-sa
        volumes:
        - name: test-volume
          configMap:
            name: cluster-capacity-configmap

apiVersion: batch/v1
kind: Job
metadata:
  name: cluster-capacity-job
spec:
  parallelism: 1
  completions: 1
  template:
    metadata:
      name: cluster-capacity-pod
    spec:
        containers:
        - name: cluster-capacity
          image: openshift/origin-cluster-capacity
          imagePullPolicy: "Always"
          volumeMounts:
          - mountPath: /test-pod
            name: test-volume
          env:
          - name: CC_INCLUSTER


            value: "true"
          command:
          - "/bin/sh"
          - "-ec"
          - |
            /bin/cluster-capacity --podspec=/test-pod/pod.yaml --verbose
        restartPolicy: "Never"
        serviceAccountName: cluster-capacity-sa
        volumes:
        - name: test-volume
          configMap:
            name: cluster-capacity-configmap

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1: 必要的环境变量，使集群容量工具知道它将作为一个 pod 在集群中运行。
ConfigMap 对象的 pod.yaml 键与 Pod spec 文件名称相同，但这不是必须的。如果这样做，输入 pod 规格文件可作为 /test-pod/pod.yaml 在 pod 中被访问。

以 pod 中作业的方式运行集群容量镜像：
```
oc create -f cluster-capacity-job.yaml
```
```
$ oc create -f cluster-capacity-job.yaml
```
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检查作业日志，以查找在集群中可调度的 pod 数量：

oc logs jobs/cluster-capacity-job

$ oc logs jobs/cluster-capacity-job

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输出示例

small-pod pod requirements:
        - CPU: 150m
        - Memory: 100Mi

The cluster can schedule 52 instance(s) of the pod small-pod.

Termination reason: Unschedulable: No nodes are available that match all of the
following predicates:: Insufficient cpu (2).

Pod distribution among nodes:
small-pod
        - 192.168.124.214: 26 instance(s)
        - 192.168.124.120: 26 instance(s)

small-pod pod requirements:
        - CPU: 150m
        - Memory: 100Mi

The cluster can schedule 52 instance(s) of the pod small-pod.

Termination reason: Unschedulable: No nodes are available that match all of the
following predicates:: Insufficient cpu (2).

Pod distribution among nodes:
small-pod
        - 192.168.124.214: 26 instance(s)
        - 192.168.124.120: 26 instance(s)

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返回顶部

7.2.3. 以 pod 中作业的方式运行集群容量工具

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