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Improve Concepts section (#17013)

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Signed-off-by: Alexey Pyltsyn <lex61rus@gmail.com>
This commit is contained in:
Alexey Pyltsyn
2019-10-28 04:49:25 +03:00
committed by Kubernetes Prow Robot
parent 7fa51c98d9
commit f120439575
7 changed files with 89 additions and 82 deletions
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content/en/docs/concepts/configuration/scheduling-framework.md
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@@ -10,7 +10,7 @@ weight: 70
{{< feature-state for_k8s_version="1.15" state="alpha" >}}
The scheduling framework is a new plugable architecture for Kubernetes Scheduler
The scheduling framework is a new pluggable architecture for Kubernetes Scheduler
that makes scheduler customizations easy. It adds a new set of "plugin" APIs to
the existing scheduler. Plugins are compiled into the scheduler. The APIs
allow most scheduling features to be implemented as plugins, while keeping the
content/en/docs/concepts/containers/container-lifecycle-hooks.md
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@@ -99,7 +99,7 @@ Here is some example output of events from running this command:
```
Events:
FirstSeen LastSeen Count From SubobjectPath Type Reason Message
FirstSeen LastSeen Count From SubObjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
1m 1m 1 {default-scheduler } Normal Scheduled Successfully assigned test-1730497541-cq1d2 to gke-test-cluster-default-pool-a07e5d30-siqd
1m 1m 1 {kubelet gke-test-cluster-default-pool-a07e5d30-siqd} spec.containers{main} Normal Pulling pulling image "test:1.0"
content/en/docs/concepts/extend-kubernetes/compute-storage-net/device-plugins.md
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@@ -13,7 +13,7 @@ Kubernetes provides a [device plugin framework](https://github.com/kubernetes/co
that you can use to advertise system hardware resources to the
{{< glossary_tooltip term_id="kubelet" >}}.
Instead of customising the code for Kubernetes itself, vendors can implement a
Instead of customizing the code for Kubernetes itself, vendors can implement a
device plugin that you deploy either manually or as a {{< glossary_tooltip term_id="daemonset" >}}.
The targeted devices include GPUs, high-performance NICs, FPGAs, InfiniBand adapters,
and other similar computing resources that may require vendor specific initialization
content/en/docs/concepts/policy/limit-range.md
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@@ -60,13 +60,13 @@ The following section discusses the creation of a LimitRange acting at Container
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
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
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
@@ -77,17 +77,16 @@ Here is the configuration file for a LimitRange object:
This object defines minimum and maximum Memory/CPU 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 in the `limitrange-demo` namespace with the following kubectl command.
Create the `limit-mem-cpu-per-container` LimitRange in the `limitrange-demo` namespace with the following kubectl command:
```shell
kubectl create -f https://k8s.io/examples/admin/resource/limit-mem-cpu-container.yaml -n limitrange-demo
```
```shell
kubectl describe limitrange/limit-mem-cpu-per-container -n limitrange-demo
```
```shell
Type Resource Min Max Default Request Default Limit Max Limit/Request Ratio
---- -------- --- --- --------------- ------------- -----------------------
@@ -95,8 +94,6 @@ 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" >}}
@@ -107,7 +104,8 @@ 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
View the `busybox-cnt01` resource configuration:
```shell
kubectl get po/busybox1 -n limitrange-demo -o json | jq ".spec.containers[0].resources"
@@ -184,13 +182,14 @@ kubectl get po/busybox1 -n limitrange-demo -o json | jq ".spec.containers[2].re
- `99Mi <= 200Mi <= 1Gi` , The container memory limit (200Mi) falls inside the authorized Memory limit range.
- No request/limits ratio set , thus the container is valid and created.
### Container spec with no CPU/Memory requests/limits
View the `busybox-cnt04` resource configuration
View the `busybox-cnt04` resource configuration:
```shell
kubectl get po/busybox1 -n limitrange-demo -o json | jq ".spec.containers[3].resources"
```
```json
{
"limits": {
@@ -215,19 +214,24 @@ kubectl get po/busybox1 -n limitrange-demo -o json | jq ".spec.containers[3].re
All containers defined in the `busybox` Pod passed LimitRange validations, this the Pod is valid and create in the namespace.
## Limiting Pod compute resources
The following section discusses how to constrain resources at Pod level.
{{< codenew file="admin/resource/limit-mem-cpu-pod.yaml" >}}
Without having to delete `busybox1` Pod, create the `limit-mem-cpu-pod` LimitRange in the `limitrange-demo` namespace
Without having to delete `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 -n limitrange-demo
```
The limitrange is created and limits CPU to 2 Core and Memory to 2Gi per Pod.
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
Describe the `limit-mem-cpu-per-pod` limit object using the following kubectl command:
```shell
kubectl describe limitrange/limit-mem-cpu-per-pod
```
@@ -240,14 +244,17 @@ Type Resource Min Max Default Request Default Limit Max Limit/Reques
Pod cpu - 2 - - -
Pod memory - 2Gi - - -
```
Now create the `busybox2` Pod.
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 -n limitrange-demo
```
The `busybox2` Pod definition is identical to `busybox1` but an error is reported since Pod's resources are now limited
The `busybox2` Pod definition is identical to `busybox1` but an error is reported since 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.]
```
@@ -259,17 +266,17 @@ kubectl get po/busybox1 -n limitrange-demo -o json | jq ".spec.containers[].re
"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.
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`.
Apply the YAML using `kubectl create`:
```shell
kubectl create -f https://k8s.io/examples/admin/resource/storagelimits.yaml -n limitrange-demo
@@ -278,12 +285,14 @@ kubectl create -f https://k8s.io/examples/admin/resource/storagelimits.yaml -n l
```shell
limitrange/storagelimits created
```
Describe the created object,
Describe the created object:
```shell
kubectl describe limits/storagelimits
```
the output should look like
The output should look like:
```shell
Name: storagelimits
@@ -299,13 +308,13 @@ PersistentVolumeClaim storage 1Gi 2Gi - - -
kubectl create -f https://k8s.io/examples/admin/resource//pvc-limit-lower.yaml -n limitrange-demo
```
While creating a PVC with `requests.storage` lower than the Min value in the LimitRange, an Error thrown by the server
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
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" >}}
@@ -321,7 +330,7 @@ Error from server (Forbidden): error when creating "pvc-limit-greater.yaml": per
If `LimitRangeItem.maxLimitRequestRatio` if specified in th `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.
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" >}}
@@ -343,30 +352,28 @@ Type Resource Min Max Default Request Default Limit Max Limit/Reques
Pod memory - - - - 2
```
Let's create a pod with `requests.memory=100Mi` and `limits.memory=300Mi`:
Let's 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
```shell
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
Delete the `limitrange-demo` namespace to free all resources:
```shell
kubectl delete ns limitrange-demo
```
## Examples
- See [a tutorial on how to limit compute resources per namespace](/docs/tasks/administer-cluster/manage-resources/cpu-constraint-namespace/) .
content/en/docs/concepts/services-networking/connect-applications-service.md
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@@ -254,9 +254,9 @@ nginxsecret Opaque 2 1m
Following are the manual steps to follow in case you run into problems running make (on windows for example):
```shell
#create a public private key pair
# Create a public private key pair
openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /d/tmp/nginx.key -out /d/tmp/nginx.crt -subj "/CN=my-nginx/O=my-nginx"
#convert the keys to base64 encoding
# Convert the keys to base64 encoding
cat /d/tmp/nginx.crt | base64
cat /d/tmp/nginx.key | base64
```
content/en/docs/concepts/workloads/controllers/deployment.md
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@@ -441,7 +441,7 @@ rolled back.
OldReplicaSets: nginx-deployment-1564180365 (3/3 replicas created)
NewReplicaSet: nginx-deployment-3066724191 (1/1 replicas created)
Events:
FirstSeen LastSeen Count From SubobjectPath Type Reason Message
FirstSeen LastSeen Count From SubObjectPath Type Reason Message
--------- -------- ----- ---- ------------- -------- ------ -------
1m 1m 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-2035384211 to 3
22s 22s 1 {deployment-controller } Normal ScalingReplicaSet Scaled up replica set nginx-deployment-1564180365 to 1