Syntax highlighting manual fixes up to mesos.md (next is scratch.md)
This commit is contained in:
John Mulhausen
@@ -40,32 +40,27 @@ This example will work in a custom namespace to demonstrate the concepts involve
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Let's create a new namespace called limit-example:
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```shell
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```shell
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$ kubectl create -f docs/admin/limitrange/namespace.yaml
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namespace "limit-example" created
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$ kubectl get namespaces
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NAME LABELS STATUS AGE
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default <none> Active 5m
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limit-example <none> Active 53s
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```
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```
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## Step 2: Apply a limit to the namespace
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Let's create a simple limit in our namespace.
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```shell
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```shell
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$ kubectl create -f docs/admin/limitrange/limits.yaml --namespace=limit-example
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limitrange "mylimits" created
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```
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```
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Let's describe the limits that we have imposed in our namespace.
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```shell
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```shell
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$ kubectl describe limits mylimits --namespace=limit-example
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Name: mylimits
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Namespace: limit-example
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@@ -75,9 +70,8 @@ Pod cpu 200m 2 - - -
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Pod memory 6Mi 1Gi - - -
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Container cpu 100m 2 200m 300m -
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Container memory 3Mi 1Gi 100Mi 200Mi -
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```
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```
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In this scenario, we have said the following:
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1. If a max constraint is specified for a resource (2 CPU and 1Gi memory in this case), then a limit
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@@ -104,20 +98,17 @@ of creation explaining why.
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Let's first spin up a replication controller that creates a single container pod to demonstrate
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how default values are applied to each pod.
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```shell
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```shell
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$ kubectl run nginx --image=nginx --replicas=1 --namespace=limit-example
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replicationcontroller "nginx" created
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$ kubectl get pods --namespace=limit-example
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NAME READY STATUS RESTARTS AGE
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nginx-aq0mf 1/1 Running 0 35s
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$ kubectl get pods nginx-aq0mf --namespace=limit-example -o yaml | grep resources -C 8
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```
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```yaml
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resourceVersion: "127"
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```
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```yaml
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resourceVersion: "127"
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selfLink: /api/v1/namespaces/limit-example/pods/nginx-aq0mf
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uid: 51be42a7-7156-11e5-9921-286ed488f785
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spec:
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@@ -134,33 +125,27 @@ spec:
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memory: 100Mi
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terminationMessagePath: /dev/termination-log
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volumeMounts:
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```
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```
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Note that our nginx container has picked up the namespace default cpu and memory resource *limits* and *requests*.
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Let's create a pod that exceeds our allowed limits by having it have a container that requests 3 cpu cores.
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```shell
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```shell
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$ kubectl create -f docs/admin/limitrange/invalid-pod.yaml --namespace=limit-example
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Error from server: error when creating "docs/admin/limitrange/invalid-pod.yaml": Pod "invalid-pod" is forbidden: [Maximum cpu usage per Pod is 2, but limit is 3., Maximum cpu usage per Container is 2, but limit is 3.]
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```
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```
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Let's create a pod that falls within the allowed limit boundaries.
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```shell
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```shell
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$ kubectl create -f docs/admin/limitrange/valid-pod.yaml --namespace=limit-example
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pod "valid-pod" created
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$ kubectl get pods valid-pod --namespace=limit-example -o yaml | grep -C 6 resources
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```
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```yaml
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uid: 162a12aa-7157-11e5-9921-286ed488f785
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```
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```yaml
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uid: 162a12aa-7157-11e5-9921-286ed488f785
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spec:
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containers:
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- image: gcr.io/google_containers/serve_hostname
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@@ -173,47 +158,36 @@ spec:
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requests:
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cpu: "1"
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memory: 512Mi
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```
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```
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Note that this pod specifies explicit resource *limits* and *requests* so it did not pick up the namespace
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default values.
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Note: The *limits* for CPU resource are not enforced in the default Kubernetes setup on the physical node
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that runs the container unless the administrator deploys the kubelet with the folllowing flag:
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```
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```
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$ kubelet --help
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Usage of kubelet
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....
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--cpu-cfs-quota[=false]: Enable CPU CFS quota enforcement for containers that specify CPU limits
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$ kubelet --cpu-cfs-quota=true ...
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```
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```
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## Step 4: Cleanup
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To remove the resources used by this example, you can just delete the limit-example namespace.
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```shell
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```shell
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$ kubectl delete namespace limit-example
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namespace "limit-example" deleted
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$ kubectl get namespaces
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NAME LABELS STATUS AGE
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default <none> Active 20m
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```
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```
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## Summary
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Cluster operators that want to restrict the amount of resources a single container or pod may consume
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are able to define allowable ranges per Kubernetes namespace. In the absence of any explicit assignments,
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the Kubernetes system is able to apply default resource *limits* and *requests* if desired in order to
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constrain the amount of resource a pod consumes on a node.
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constrain the amount of resource a pod consumes on a node.
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@@ -40,32 +40,27 @@ This example will work in a custom namespace to demonstrate the concepts involve
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Let's create a new namespace called limit-example:
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```shell
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```shell
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$ kubectl create -f docs/admin/limitrange/namespace.yaml
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namespace "limit-example" created
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$ kubectl get namespaces
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NAME LABELS STATUS AGE
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default <none> Active 5m
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limit-example <none> Active 53s
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```
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```
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## Step 2: Apply a limit to the namespace
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Let's create a simple limit in our namespace.
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```shell
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```shell
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$ kubectl create -f docs/admin/limitrange/limits.yaml --namespace=limit-example
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limitrange "mylimits" created
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```
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```
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Let's describe the limits that we have imposed in our namespace.
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```shell
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```shell
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$ kubectl describe limits mylimits --namespace=limit-example
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Name: mylimits
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Namespace: limit-example
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@@ -75,9 +70,8 @@ Pod cpu 200m 2 - - -
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Pod memory 6Mi 1Gi - - -
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Container cpu 100m 2 200m 300m -
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Container memory 3Mi 1Gi 100Mi 200Mi -
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```
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```
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In this scenario, we have said the following:
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1. If a max constraint is specified for a resource (2 CPU and 1Gi memory in this case), then a limit
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@@ -104,20 +98,17 @@ of creation explaining why.
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Let's first spin up a replication controller that creates a single container pod to demonstrate
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how default values are applied to each pod.
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```shell
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```shell
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$ kubectl run nginx --image=nginx --replicas=1 --namespace=limit-example
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replicationcontroller "nginx" created
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$ kubectl get pods --namespace=limit-example
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NAME READY STATUS RESTARTS AGE
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nginx-aq0mf 1/1 Running 0 35s
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$ kubectl get pods nginx-aq0mf --namespace=limit-example -o yaml | grep resources -C 8
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```
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```yaml
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resourceVersion: "127"
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```
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```yaml
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resourceVersion: "127"
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selfLink: /api/v1/namespaces/limit-example/pods/nginx-aq0mf
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uid: 51be42a7-7156-11e5-9921-286ed488f785
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spec:
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@@ -134,33 +125,27 @@ spec:
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memory: 100Mi
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terminationMessagePath: /dev/termination-log
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volumeMounts:
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```
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```
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Note that our nginx container has picked up the namespace default cpu and memory resource *limits* and *requests*.
|
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Let's create a pod that exceeds our allowed limits by having it have a container that requests 3 cpu cores.
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```shell
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```shell
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$ kubectl create -f docs/admin/limitrange/invalid-pod.yaml --namespace=limit-example
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Error from server: error when creating "docs/admin/limitrange/invalid-pod.yaml": Pod "invalid-pod" is forbidden: [Maximum cpu usage per Pod is 2, but limit is 3., Maximum cpu usage per Container is 2, but limit is 3.]
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```
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```
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Let's create a pod that falls within the allowed limit boundaries.
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```shell
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```shell
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$ kubectl create -f docs/admin/limitrange/valid-pod.yaml --namespace=limit-example
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pod "valid-pod" created
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$ kubectl get pods valid-pod --namespace=limit-example -o yaml | grep -C 6 resources
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```
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```yaml
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uid: 162a12aa-7157-11e5-9921-286ed488f785
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```
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```yaml
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uid: 162a12aa-7157-11e5-9921-286ed488f785
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spec:
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containers:
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- image: gcr.io/google_containers/serve_hostname
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@@ -173,47 +158,37 @@ spec:
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requests:
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cpu: "1"
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memory: 512Mi
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```
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```
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Note that this pod specifies explicit resource *limits* and *requests* so it did not pick up the namespace
|
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default values.
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|
||||
Note: The *limits* for CPU resource are not enforced in the default Kubernetes setup on the physical node
|
||||
that runs the container unless the administrator deploys the kubelet with the folllowing flag:
|
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|
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```
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|
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```shell
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$ kubelet --help
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Usage of kubelet
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....
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--cpu-cfs-quota[=false]: Enable CPU CFS quota enforcement for containers that specify CPU limits
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$ kubelet --cpu-cfs-quota=true ...
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|
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```
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```
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## Step 4: Cleanup
|
||||
|
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To remove the resources used by this example, you can just delete the limit-example namespace.
|
||||
|
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```shell
|
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|
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```shell
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$ kubectl delete namespace limit-example
|
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namespace "limit-example" deleted
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$ kubectl get namespaces
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NAME LABELS STATUS AGE
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default <none> Active 20m
|
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|
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```
|
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```
|
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## Summary
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Cluster operators that want to restrict the amount of resources a single container or pod may consume
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are able to define allowable ranges per Kubernetes namespace. In the absence of any explicit assignments,
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the Kubernetes system is able to apply default resource *limits* and *requests* if desired in order to
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constrain the amount of resource a pod consumes on a node.
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|
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|
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|
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|
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constrain the amount of resource a pod consumes on a node.
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