Start new task for Opaque Integer Resources. (#4363)
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Steve Perry
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---
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title: Advertise Opaque Integer Resources for a Node
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---
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{% capture overview %}
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This page shows how to specify opaque integer resources for a Node.
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Opaque integer resources allow cluster administrators to advertise node-level
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resources that would otherwise be unknown to Kubernetes.
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{% include feature-state-alpha.md %}
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{% endcapture %}
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{% capture prerequisites %}
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{% include task-tutorial-prereqs.md %}
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{% endcapture %}
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{% capture steps %}
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## Get the names of your Nodes
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```shell
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kubectl get nodes
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```
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Choose one of your Nodes to use for this exercise.
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## Advertise a new opaque integer resource on one of your Nodes
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To advertise a new opaque integer resource on a Node, send an HTTP PATCH request to
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the Kubernetes API server. For example, suppose one of your Nodes has four dongles
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attached. Here's an example of a PATCH request that advertises four dongle resources
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for your Node.
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```shell
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PATCH /api/v1/nodes/<your-node-name>/status HTTP/1.1
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Accept: application/json
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Content-Type: application/json-patch+json
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Host: k8s-master:8080
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[
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{
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"op": "add",
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"path": "/status/capacity/pod.alpha.kubernetes.io~1opaque-int-resource-dongle",
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"value": "4"
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}
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]
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```
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Note that Kubernetes does not need to know what a dongle is or what a dongle is for.
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The preceding PATCH request just tells Kubernetes that your Node has four things that
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you call dongles.
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Start a proxy, so that you can easily send requests to the Kubernetes API server:
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```
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kubectl proxy
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```
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In another command window, send the HTTP PATCH request.
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Replace `<your-node-name>` with the name of your Node:
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```shell
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curl --header "Content-Type: application/json-patch+json" \
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--request PATCH \
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--data '[{"op": "add", "path": "/status/capacity/pod.alpha.kubernetes.io~1opaque-int-resource-dongle", "value": "4"}]' \
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http://localhost:8001/api/v1/nodes/<your-node-name>/status
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```
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**Note**: In the preceding request, `~1` is the encoding for the character / in
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the patch path. The operation path value in JSON-Patch is interpreted as a
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JSON-Pointer. For more details, see
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[IETF RFC 6901](https://tools.ietf.org/html/rfc6901), section 3.
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The output shows that the Node has a capacity of 4 dongles:
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```
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"capacity": {
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"alpha.kubernetes.io/nvidia-gpu": "0",
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"cpu": "2",
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"memory": "2049008Ki",
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"pod.alpha.kubernetes.io/opaque-int-resource-dongle": "4",
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```
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Describe your Node:
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```
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kubectl describe node <your-node-name>
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```
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Once again, the output shows the dongle resource:
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```yaml
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Capacity:
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alpha.kubernetes.io/nvidia-gpu: 0
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cpu: 2
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memory: 2049008Ki
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pod.alpha.kubernetes.io/opaque-int-resource-dongle: 4
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```
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Now, application developers can create Pods that request a certain
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number of dongles. See
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[Assign Opaque Integer Resources to a Container](/docs/tasks/configure-pod-container/opaque-integer-resource/).
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## Discussion
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Opaque integer resources are similar to memory and CPU resources. For example,
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just as a Node has a certain amount of memory and CPU to be shared by all components
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running on the Node, it can have a certain number of dongles to be shared
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by all components running on the Node. And just as application developers
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can create Pods that request a certain amount of memory and CPU, they can
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create Pods that request a certain number of dongles.
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Opaque integer resources are called opaque because Kubernetes does not
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know anything about what they are. Kubernetes knows only that a Node
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has a certain number of them. They are called integer resources because
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they must be advertised in integer amounts. For example, a Node can advertise
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four dongles, but not 4.5 dongles.
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### Storage example
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Suppose a Node has 800 GiB of a special kind of disk storage. You could
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create a name for the special storage, say opaque-int-resource-special-storage.
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Then you could advertise it in chunks of a certain size, say 100 GiB. In that case,
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your Node would advertise that it has eight resources of type
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opaque-int-resource-special-storage.
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```yaml
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Capacity:
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...
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pod.alpha.kubernetes.io/opaque-int-special-storage: 8
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```
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If you want to allow arbitrary requests for special storage, you
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could advertise special storage in chunks of size 1 byte. In that case, you would advertise
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800Gi resources of type opaque-int-resource-special-storage.
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```yaml
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Capacity:
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...
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pod.alpha.kubernetes.io/opaque-int-special-storage: 8Gi
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```
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Then a Container could request any number of bytes of special storage, up to 800Gi.
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## Clean up
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Here is a PATCH request that removes the dongle advertisement from a Node.
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```shell
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PATCH /api/v1/nodes/<your-node-name>/status HTTP/1.1
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Accept: application/json
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Content-Type: application/json-patch+json
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Host: k8s-master:8080
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[
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{
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"op": "remove",
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"path": "/status/capacity/pod.alpha.kubernetes.io~1opaque-int-resource-dongle",
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}
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]
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```
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Start a proxy, so that you can easily send requests to the Kubernetes API server:
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```
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kubectl proxy
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```
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In another command window, send the HTTP PATCH request.
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Replace `<your-node-name>` with the name of your Node:
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```shell
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curl --header "Content-Type: application/json-patch+json" \
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--request PATCH \
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--data '[{"op": "remove", "path": "/status/capacity/pod.alpha.kubernetes.io~1opaque-int-resource-dongle"}]' \
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http://localhost:8001/api/v1/nodes/<your-node-name>/status
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```
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Verify that the dongle advertisement has been removed:
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```
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kubectl describe node <your-node-name> | grep dongle
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```
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{% endcapture %}
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{% capture whatsnext %}
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### For application developers
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* [Assign Opaque Integer Resources to a Container](/docs/tasks/configure-pod-container/opaque-integer-resource/)
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### For cluster administrators
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* [Configure Minimum and Maximum Memory Constraints for a Namespace](/docs/tasks/administer-cluster/memory-constraint-namespace/)
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* [Configure Minimum and Maximum CPU Constraints for a Namespace](/docs/tasks/administer-cluster/cpu-constraint-namespace/)
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{% endcapture %}
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{% include templates/task.md %}
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