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70 lines
2.1 KiB
Plaintext
70 lines
2.1 KiB
Plaintext
// Module included in the following assemblies:
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//
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// * nodes/nodes-containers-downward-api.adoc
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[id="nodes-containers-downward-api-container-resources-plugin_{context}"]
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= Consuming container resources using a volume plug-in
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When creating pods, you can use the downward API to inject information about
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computing resource requests and limits using a volume plug-in.
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.Procedure
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To use the Volume Plug-in:
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. When creating a pod configuration, use the `*spec.volumes.downwardAPI.items*`
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field to describe the desired resources that correspond to the
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`*spec.resources*` field:
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+
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[source,yaml]
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----
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....
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spec:
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containers:
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- name: client-container
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image: gcr.io/google_containers/busybox:1.24
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command: ["sh", "-c", "while true; do echo; if [[ -e /etc/cpu_limit ]]; then cat /etc/cpu_limit; fi; if [[ -e /etc/cpu_request ]]; then cat /etc/cpu_request; fi; if [[ -e /etc/mem_limit ]]; then cat /etc/mem_limit; fi; if [[ -e /etc/mem_request ]]; then cat /etc/mem_request; fi; sleep 5; done"]
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resources:
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requests:
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memory: "32Mi"
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cpu: "125m"
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limits:
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memory: "64Mi"
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cpu: "250m"
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volumeMounts:
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- name: podinfo
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mountPath: /etc
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readOnly: false
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volumes:
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- name: podinfo
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downwardAPI:
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items:
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- path: "cpu_limit"
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resourceFieldRef:
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containerName: client-container
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resource: limits.cpu
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- path: "cpu_request"
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resourceFieldRef:
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containerName: client-container
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resource: requests.cpu
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- path: "mem_limit"
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resourceFieldRef:
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containerName: client-container
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resource: limits.memory
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- path: "mem_request"
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resourceFieldRef:
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containerName: client-container
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resource: requests.memory
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....
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----
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+
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If the resource limits are not included in the container configuration, the
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downward API defaults to the node's CPU and memory allocatable values.
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. Create the pod from the `*_volume-pod.yaml_*` file:
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+
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[source,terminal]
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----
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$ oc create -f volume-pod.yaml
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----
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