Tidy resource management task pages
Revise tasks within “Manage Memory, CPU, and API Resources”: - reword to avoid implying that API clients can create a container (you can, but its done by creating a Pod) - call a manifest a manifest - use tooltips where relevant - link to new API reference not the old one - other improvements
This commit is contained in:
Tim Bannister
+35
-29
@@ -7,9 +7,10 @@ weight: 40
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<!-- overview -->
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This page shows how to set minimum and maximum values for the CPU resources used by Containers
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and Pods in a namespace. You specify minimum and maximum CPU values in a
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[LimitRange](/docs/reference/generated/kubernetes-api/{{< param "version" >}}/#limitrange-v1-core)
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This page shows how to set minimum and maximum values for the CPU resources used by containers
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and Pods in a {{< glossary_tooltip text="namespace" term_id="namespace" >}}. You specify minimum
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and maximum CPU values in a
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[LimitRange](/docs/reference/kubernetes-api/policy-resources/limit-range-v1/)
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object. If a Pod does not meet the constraints imposed by the LimitRange, it cannot be created
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in the namespace.
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@@ -19,11 +20,13 @@ in the namespace.
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## {{% heading "prerequisites" %}}
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{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
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Your cluster must have at least 1 CPU available for use to run the task examples.
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{{< include "task-tutorial-prereqs.md" >}}
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You must have access to create namespaces in your cluster.
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Your cluster must have at least 1.0 CPU available for use to run the task examples.
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See [meaning of CPU](/docs/concepts/configuration/manage-resources-containers/#meaning-of-cpu)
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to learn what Kubernetes means by “1 CPU”.
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<!-- steps -->
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@@ -39,7 +42,7 @@ kubectl create namespace constraints-cpu-example
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## Create a LimitRange and a Pod
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Here's the configuration file for a LimitRange:
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Here's an example manifest for a LimitRange:
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{{< codenew file="admin/resource/cpu-constraints.yaml" >}}
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@@ -72,15 +75,15 @@ limits:
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type: Container
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```
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Now whenever a Container is created in the constraints-cpu-example namespace, Kubernetes
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performs these steps:
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Now whenever you create a Pod in the constraints-cpu-example namespace (or some other client
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of the Kubernetes API creates an equivalent Pod), Kubernetes performs these steps:
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* If the Container does not specify its own CPU request and limit, assign the default
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CPU request and limit to the Container.
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* If any container in that Pod does not specify its own CPU request and limit, the control plane
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assigns the default CPU request and limit to that container.
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* Verify that the Container specifies a CPU request that is greater than or equal to 200 millicpu.
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* Verify that every container in that Pod specifies a CPU request that is greater than or equal to 200 millicpu.
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* Verify that the Container specifies a CPU limit that is less than or equal to 800 millicpu.
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* Verify that every container in that Pod specifies a CPU limit that is less than or equal to 800 millicpu.
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{{< note >}}
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When creating a `LimitRange` object, you can specify limits on huge-pages
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@@ -88,7 +91,7 @@ or GPUs as well. However, when both `default` and `defaultRequest` are specified
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on these resources, the two values must be the same.
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{{< /note >}}
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Here's the configuration file for a Pod that has one Container. The Container manifest
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Here's a manifest for a Pod that has one container. The container manifest
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specifies a CPU request of 500 millicpu and a CPU limit of 800 millicpu. These satisfy the
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minimum and maximum CPU constraints imposed by the LimitRange.
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@@ -100,7 +103,7 @@ Create the Pod:
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kubectl apply -f https://k8s.io/examples/admin/resource/cpu-constraints-pod.yaml --namespace=constraints-cpu-example
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```
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Verify that the Pod's Container is running:
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Verify that the Pod is running and that its container is healthy:
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```shell
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kubectl get pod constraints-cpu-demo --namespace=constraints-cpu-example
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@@ -112,7 +115,7 @@ View detailed information about the Pod:
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kubectl get pod constraints-cpu-demo --output=yaml --namespace=constraints-cpu-example
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```
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The output shows that the Container has a CPU request of 500 millicpu and CPU limit
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The output shows that the Pod's only container has a CPU request of 500 millicpu and CPU limit
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of 800 millicpu. These satisfy the constraints imposed by the LimitRange.
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```yaml
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@@ -131,7 +134,7 @@ kubectl delete pod constraints-cpu-demo --namespace=constraints-cpu-example
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## Attempt to create a Pod that exceeds the maximum CPU constraint
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Here's the configuration file for a Pod that has one Container. The Container specifies a
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Here's a manifest for a Pod that has one container. The container specifies a
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CPU request of 500 millicpu and a cpu limit of 1.5 cpu.
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{{< codenew file="admin/resource/cpu-constraints-pod-2.yaml" >}}
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@@ -142,8 +145,8 @@ Attempt to create the Pod:
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kubectl apply -f https://k8s.io/examples/admin/resource/cpu-constraints-pod-2.yaml --namespace=constraints-cpu-example
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```
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The output shows that the Pod does not get created, because the Container specifies a CPU limit that is
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too large:
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The output shows that the Pod does not get created, because it defines an unacceptable container.
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That container is not acceptable because it specifies a CPU limit that is too large:
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```
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Error from server (Forbidden): error when creating "examples/admin/resource/cpu-constraints-pod-2.yaml":
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@@ -152,7 +155,7 @@ pods "constraints-cpu-demo-2" is forbidden: maximum cpu usage per Container is 8
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## Attempt to create a Pod that does not meet the minimum CPU request
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Here's the configuration file for a Pod that has one Container. The Container specifies a
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Here's a manifest for a Pod that has one container. The container specifies a
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CPU request of 100 millicpu and a CPU limit of 800 millicpu.
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{{< codenew file="admin/resource/cpu-constraints-pod-3.yaml" >}}
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@@ -163,8 +166,9 @@ Attempt to create the Pod:
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kubectl apply -f https://k8s.io/examples/admin/resource/cpu-constraints-pod-3.yaml --namespace=constraints-cpu-example
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```
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The output shows that the Pod does not get created, because the Container specifies a CPU
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request that is too small:
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The output shows that the Pod does not get created, because it defines an unacceptable container.
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That container is not acceptable because it specifies a CPU limit that is lower than the
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enforced minimum:
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```
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Error from server (Forbidden): error when creating "examples/admin/resource/cpu-constraints-pod-3.yaml":
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@@ -173,8 +177,8 @@ pods "constraints-cpu-demo-3" is forbidden: minimum cpu usage per Container is 2
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## Create a Pod that does not specify any CPU request or limit
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Here's the configuration file for a Pod that has one Container. The Container does not
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specify a CPU request, and it does not specify a CPU limit.
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Here's a manifest for a Pod that has one container. The container does not
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specify a CPU request, nor does it specify a CPU limit.
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{{< codenew file="admin/resource/cpu-constraints-pod-4.yaml" >}}
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@@ -190,8 +194,9 @@ View detailed information about the Pod:
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kubectl get pod constraints-cpu-demo-4 --namespace=constraints-cpu-example --output=yaml
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```
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The output shows that the Pod's Container has a CPU request of 800 millicpu and a CPU limit of 800 millicpu.
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How did the Container get those values?
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The output shows that the Pod's single container has a CPU request of 800 millicpu and a
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CPU limit of 800 millicpu.
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How did that container get those values?
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```yaml
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resources:
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@@ -201,11 +206,12 @@ resources:
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cpu: 800m
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```
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Because your Container did not specify its own CPU request and limit, it was given the
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Because that container did not specify its own CPU request and limit, the control plane
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applied the
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[default CPU request and limit](/docs/tasks/administer-cluster/manage-resources/cpu-default-namespace/)
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from the LimitRange.
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from the LimitRange for this namespace.
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At this point, your Container might be running or it might not be running. Recall that a prerequisite for this task is that your cluster must have at least 1 CPU available for use. If each of your Nodes has only 1 CPU, then there might not be enough allocatable CPU on any Node to accommodate a request of 800 millicpu. If you happen to be using Nodes with 2 CPU, then you probably have enough CPU to accommodate the 800 millicpu request.
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At this point, your Pod might be running or it might not be running. Recall that a prerequisite for this task is that your cluster must have at least 1 CPU available for use. If each of your Nodes has only 1 CPU, then there might not be enough allocatable CPU on any Node to accommodate a request of 800 millicpu. If you happen to be using Nodes with 2 CPU, then you probably have enough CPU to accommodate the 800 millicpu request.
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Delete your Pod:
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