Merge pull request #20085 from davivcgarcia/davivcgarcia-issue-19847

k8s-ci-robot · web-flow · commit e649d9e49b0f · 2020-04-04T12:39:45.000-07:00
Replace embedded examples with links to related task docs
diff --git a/content/en/docs/concepts/policy/limit-range.md b/content/en/docs/concepts/policy/limit-range.md
@@ -56,337 +56,14 @@ there may be contention for resources. In this case, the Containers or Pods will
 
 Neither contention nor changes to a LimitRange will affect already created resources.
 
-## Limiting Container compute resources
-
-The following section discusses the creation of a LimitRange acting at Container Level.
-A Pod with 04 Containers is first created. Each Container within the Pod has a specific `spec.resource` configuration.
-Each Container within the Pod is handled differently by the `LimitRanger` admission controller.
-
-Create a namespace `limitrange-demo` using the following kubectl command:
-
-```shell
-kubectl create namespace limitrange-demo
-```
-
-To avoid passing the target limitrange-demo in your kubectl commands, change your context with the following command:
-
-```shell
-kubectl config set-context --current --namespace=limitrange-demo
-```
-
-Here is the configuration file for a LimitRange object:
-{{< codenew file="admin/resource/limit-mem-cpu-container.yaml" >}}
-
-This object defines minimum and maximum CPU/Memory limits, default CPU/Memory requests, and default limits for CPU/Memory resources to be apply to containers.
-
-Create the `limit-mem-cpu-per-container` LimitRange with the following kubectl command:
-
-```shell
-kubectl create -f https://k8s.io/examples/admin/resource/limit-mem-cpu-container.yaml
-```
-
-```shell
-kubectl describe limitrange/limit-mem-cpu-per-container
-```
-
-```shell
-Type        Resource  Min   Max   Default Request  Default Limit  Max Limit/Request Ratio
-----        --------  ---   ---   ---------------  -------------  -----------------------
-Container   cpu       100m  800m  110m             700m           -
-Container   memory    99Mi  1Gi   111Mi            900Mi          -
-```
-
-Here is the configuration file for a Pod with 04 Containers to demonstrate LimitRange features:
-{{< codenew file="admin/resource/limit-range-pod-1.yaml" >}}
-
-Create the `busybox1` Pod:
-
-```shell
-kubectl apply -f https://k8s.io/examples/admin/resource/limit-range-pod-1.yaml
-```
-
-### Container spec with valid CPU/Memory requests and limits
-
-View the `busybox-cnt01` resource configuration:
-
-```shell
-kubectl get po/busybox1 -o json | jq ".spec.containers[0].resources"
-```
-
-```json
-{
-  "limits": {
-    "cpu": "500m",
-    "memory": "200Mi"
-  },
-  "requests": {
-    "cpu": "100m",
-    "memory": "100Mi"
-  }
-}
-```
-
-- The `busybox-cnt01` Container inside `busybox` Pod defined `requests.cpu=100m` and `requests.memory=100Mi`.
--  `100m <= 500m <= 800m` , The Container cpu limit (500m) falls inside the authorized CPU LimitRange.
--  `99Mi <= 200Mi <= 1Gi` , The Container memory limit (200Mi) falls inside the authorized Memory LimitRange.
--  No request/limits ratio validation for CPU/Memory, so the Container is valid and created.
-
-
-### Container spec with a valid  CPU/Memory requests but no limits
-
-View the  `busybox-cnt02` resource configuration
-
-```shell
-kubectl get po/busybox1 -o json | jq ".spec.containers[1].resources"
-```
-
-```json
-{
-  "limits": {
-    "cpu": "700m",
-    "memory": "900Mi"
-  },
-  "requests": {
-    "cpu": "100m",
-    "memory": "100Mi"
-  }
-}
-```
--  The `busybox-cnt02` Container inside `busybox1` Pod defined `requests.cpu=100m` and `requests.memory=100Mi` but not limits for cpu and memory.
--  The Container does not have a limits section. The default limits defined in the `limit-mem-cpu-per-container` LimitRange object are injected in to this Container: `limits.cpu=700mi` and `limits.memory=900Mi`.
--  `100m <= 700m <= 800m` , The Container cpu limit (700m) falls inside the authorized CPU limit range.
--  `99Mi <= 900Mi <= 1Gi` , The Container memory limit (900Mi) falls inside the authorized Memory limit range.
--  No request/limits ratio set, so the Container is valid and created.
-
-
-### Container spec with a valid CPU/Memory limits but no requests
-
-View the `busybox-cnt03` resource configuration:
-
-```shell
-kubectl get po/busybox1 -o json | jq ".spec.containers[2].resources"
-```
-```json
-{
-  "limits": {
-    "cpu": "500m",
-    "memory": "200Mi"
-  },
-  "requests": {
-    "cpu": "500m",
-    "memory": "200Mi"
-  }
-}
-```
-
--  The `busybox-cnt03` Container inside `busybox1` Pod defined `limits.cpu=500m` and `limits.memory=200Mi` but no `requests` for cpu and memory.
--  The Container does not define a request section. The default request defined in the limit-mem-cpu-per-container LimitRange is not used to fill its limits section, but the limits defined by the Container are set as requests `limits.cpu=500m` and `limits.memory=200Mi`.
--  `100m <= 500m <= 800m` , The Container cpu limit (500m) falls inside the authorized CPU limit range.
--  `99Mi <= 200Mi <= 1Gi` , The Container memory limit (200Mi) falls inside the authorized Memory limit range.
--  No request/limits ratio set, so the Container is valid and created.
-
-### Container spec with no CPU/Memory requests/limits
-
-View the `busybox-cnt04` resource configuration:
-
-```shell
-kubectl get po/busybox1 -o json | jq ".spec.containers[3].resources"
-```
-
-```json
-{
-  "limits": {
-    "cpu": "700m",
-    "memory": "900Mi"
-  },
-  "requests": {
-    "cpu": "110m",
-    "memory": "111Mi"
-  }
-}
-```
-
--  The `busybox-cnt04` Container inside `busybox1` define neither `limits` nor  `requests`.
--  The Container do not define a limit section, the default limit defined in the limit-mem-cpu-per-container LimitRange is used to fill its request
-   `limits.cpu=700m and` `limits.memory=900Mi` .
--  The Container do not define a request section, the defaultRequest defined in the `limit-mem-cpu-per-container` LimitRange is used to fill its request section requests.cpu=110m and requests.memory=111Mi
--  `100m <= 700m <= 800m` , The Container cpu limit (700m) falls inside the authorized CPU limit range.
--  `99Mi <= 900Mi <= 1Gi` , The Container memory limit (900Mi) falls inside the authorized Memory limit range .
--  No request/limits ratio set, so the Container is valid and created.
-
-All Containers defined in the `busybox` Pod passed LimitRange validations, so this the Pod is valid and created in the namespace.
-
-## Limiting Pod compute resources
-
-The following section discusses how to constrain resources at the Pod level.
-
-{{< codenew file="admin/resource/limit-mem-cpu-pod.yaml" >}}
-
-Without having to delete the `busybox1` Pod, create the `limit-mem-cpu-pod` LimitRange in the `limitrange-demo` namespace:
-
-```shell
-kubectl apply -f https://k8s.io/examples/admin/resource/limit-mem-cpu-pod.yaml
-```
-The LimitRange is created and limits CPU to 2 Core and Memory to 2Gi per Pod:
-
-```shell
-limitrange/limit-mem-cpu-per-pod created
-```
-
-Describe the `limit-mem-cpu-per-pod` limit object using the following kubectl command:
-
-```shell
-kubectl describe limitrange/limit-mem-cpu-per-pod
-```
-
-```shell
-Name:       limit-mem-cpu-per-pod
-Namespace:  limitrange-demo
-Type        Resource  Min  Max  Default Request  Default Limit  Max Limit/Request Ratio
-----        --------  ---  ---  ---------------  -------------  -----------------------
-Pod         cpu       -    2    -                -              -
-Pod         memory    -    2Gi  -                -              -
-```
-
-Now create the `busybox2` Pod:
-
-{{< codenew file="admin/resource/limit-range-pod-2.yaml" >}}
-
-```shell
-kubectl apply -f https://k8s.io/examples/admin/resource/limit-range-pod-2.yaml
-```
-
-The `busybox2` Pod definition is identical to `busybox1`, but an error is reported since the Pod's resources are now limited:
-
-```shell
-Error from server (Forbidden): error when creating "limit-range-pod-2.yaml": pods "busybox2" is forbidden: [maximum cpu usage per Pod is 2, but limit is 2400m., maximum memory usage per Pod is 2Gi, but limit is 2306867200.]
-```
-
-```shell
-kubectl get po/busybox1 -o json | jq ".spec.containers[].resources.limits.memory"
-"200Mi"
-"900Mi"
-"200Mi"
-"900Mi"
-```
-
-`busybox2` Pod will not be admitted on the cluster since the total memory limit of its Container is greater than the limit defined in the LimitRange.
-`busybox1` will not be evicted since it was created and admitted on the cluster before the LimitRange creation.
-
-## Limiting Storage resources
-
-You can enforce minimum and maximum size of [storage resources](/docs/concepts/storage/persistent-volumes/) that can be requested by each PersistentVolumeClaim in a namespace using a LimitRange:
-
-{{< codenew file="admin/resource/storagelimits.yaml" >}}
-
-Apply the YAML using `kubectl create`:
-
-```shell
-kubectl create -f https://k8s.io/examples/admin/resource/storagelimits.yaml
-```
-
-```shell
-limitrange/storagelimits created
-```
-
-Describe the created object:
-
-```shell
-kubectl describe limits/storagelimits
-```
-
-The output should look like:
-
-```shell
-Name:                  storagelimits
-Namespace:             limitrange-demo
-Type                   Resource  Min  Max  Default Request  Default Limit  Max Limit/Request Ratio
-----                   --------  ---  ---  ---------------  -------------  -----------------------
-PersistentVolumeClaim  storage   1Gi  2Gi  -                -              -
-```
-
-{{< codenew file="admin/resource/pvc-limit-lower.yaml" >}}
-
-```shell
-kubectl create -f https://k8s.io/examples/admin/resource/pvc-limit-lower.yaml
-```
-
-While creating a PVC with `requests.storage` lower than the Min value in the LimitRange, an Error thrown by the server:
-
-```shell
-Error from server (Forbidden): error when creating "pvc-limit-lower.yaml": persistentvolumeclaims "pvc-limit-lower" is forbidden: minimum storage usage per PersistentVolumeClaim is 1Gi, but request is 500Mi.
-```
-
-Same behaviour is noted if  the `requests.storage` is greater than the Max value in the LimitRange:
-
-{{< codenew file="admin/resource/pvc-limit-greater.yaml" >}}
-
-```shell
-kubectl create -f https://k8s.io/examples/admin/resource/pvc-limit-greater.yaml
-```
-
-```shell
-Error from server (Forbidden): error when creating "pvc-limit-greater.yaml": persistentvolumeclaims "pvc-limit-greater" is forbidden: maximum storage usage per PersistentVolumeClaim is 2Gi, but request is 5Gi.
-```
-
-## Limits/Requests Ratio
-
-If `LimitRangeItem.maxLimitRequestRatio` is specified in the `LimitRangeSpec`, the named resource must have a request and limit that are both non-zero where limit divided by request is less than or equal to the enumerated value.
-
-The following LimitRange enforces memory limit to be at most twice the amount of the memory request for any Pod in the namespace:
-
-{{< codenew file="admin/resource/limit-memory-ratio-pod.yaml" >}}
-
-```shell
-kubectl apply -f https://k8s.io/examples/admin/resource/limit-memory-ratio-pod.yaml
-```
-
-Describe the <limit-memory-ratio-pod> LimitRange with the following kubectl command:
-
-```shell
-kubectl describe limitrange/limit-memory-ratio-pod
-```
-
-```shell
-Name:       limit-memory-ratio-pod
-Namespace:  limitrange-demo
-Type        Resource  Min  Max  Default Request  Default Limit  Max Limit/Request Ratio
-----        --------  ---  ---  ---------------  -------------  -----------------------
-Pod         memory    -    -    -                -              2
-```
-
-Create a pod with `requests.memory=100Mi` and `limits.memory=300Mi`:
-
-{{< codenew file="admin/resource/limit-range-pod-3.yaml" >}}
-
-```shell
-kubectl apply -f https://k8s.io/examples/admin/resource/limit-range-pod-3.yaml
-```
-
-The pod creation failed as the ratio here (`3`) is greater than the enforced limit (`2`) in `limit-memory-ratio-pod` LimitRange:
-
-```
-Error from server (Forbidden): error when creating "limit-range-pod-3.yaml": pods "busybox3" is forbidden: memory max limit to request ratio per Pod is 2, but provided ratio is 3.000000.
-```
-
-## Clean up
-
-Delete the `limitrange-demo` namespace to free all resources:
-
-```shell
-kubectl delete ns limitrange-demo
-```
-Change your context to `default` namespace with the following command:
-
-```shell
-kubectl config set-context --current --namespace=default
-```
-
 ## Examples
 
-- See  [a tutorial on how to limit compute resources per namespace](/docs/tasks/administer-cluster/manage-resources/cpu-constraint-namespace/) .
-- Check [how to limit storage consumption](/docs/tasks/administer-cluster/limit-storage-consumption/#limitrange-to-limit-requests-for-storage).
-- See a [detailed example on quota per namespace](/docs/tasks/administer-cluster/quota-memory-cpu-namespace/).
+- See [how to configure minimum and maximum CPU constraints per namespace](/docs/tasks/administer-cluster/manage-resources/cpu-constraint-namespace/).
+- See [how to configure minimum and maximum Memory constraints per namespace](https://kubernetes.io/docs/tasks/administer-cluster/manage-resources/memory-constraint-namespace/).
+- See [how to configure default CPU Requests and Limits per namespace](https://kubernetes.io/docs/tasks/administer-cluster/manage-resources/cpu-default-namespace/).
+- See [how to configure default Memory Requests and Limits per namespace](https://kubernetes.io/docs/tasks/administer-cluster/manage-resources/memory-default-namespace/).
+- Check [how to configure minimum and maximum Storage consumption per namespace](/docs/tasks/administer-cluster/limit-storage-consumption/#limitrange-to-limit-requests-for-storage).
+- See a [detailed example on configuring quota per namespace](/docs/tasks/administer-cluster/quota-memory-cpu-namespace/).
 
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