whentimeslows/website
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Made CPU usage consistent and removed apostrophes (#10044)

Browse Source 
* Made CPU usage consistent and removed apostrophes

* Update assign-cpu-resource.md
This commit is contained in:
Julie Bruce
2018-08-22 10:58:09 -05:00
committed by k8s-ci-robot
parent 6d3d89198e
commit 5752cde1fa
1 changed files with 29 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files
content/en/docs/tasks/configure-pod-container/assign-cpu-resource.md
+29 -33
View File
@@ -18,11 +18,11 @@ but is not allowed to use more CPU than its limit.
{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}} {{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
Each node in your cluster must have at least 1 cpu. Each node in your cluster must have at least 1 CPU.
A few of the steps on this page require you to run the A few of the steps on this page require you to run the
[metrics-server](https://github.com/kubernetes-incubator/metrics-server) [metrics-server](https://github.com/kubernetes-incubator/metrics-server)
service in your cluster. If you don't have metrics-server service in your cluster. If you do not have the metrics-server
running, you can skip those steps. running, you can skip those steps.
If you are running minikube, run the following command to enable If you are running minikube, run the following command to enable
@@ -33,7 +33,7 @@ minikube addons enable metrics-server
``` ```
To see whether metrics-server (or another provider of the resource metrics To see whether metrics-server (or another provider of the resource metrics
API, `metrics.k8s.io`) is running, enter this command: API, `metrics.k8s.io`) is running, type the following command:
```shell ```shell
kubectl get apiservices kubectl get apiservices
@@ -65,16 +65,14 @@ kubectl create namespace cpu-example
## Specify a CPU request and a CPU limit ## Specify a CPU request and a CPU limit
To specify a CPU request for a Container, include the `resources:requests` field To specify a CPU request for a Container, include the `resources:requests` field
in the Container's resource manifest. To specify a CPU limit, include `resources:limits`. in the Container resource manifest. To specify a CPU limit, include `resources:limits`.
In this exercise, you create a Pod that has one Container. The Container has a CPU In this exercise, you create a Pod that has one Container. The Container has a request of 0.5 CPU and a limit of 1 CPU. Here is the configuration file for the Pod:
request of 0.5 cpu and a CPU limit of 1 cpu. Here's the configuration file
for the Pod:
{{< codenew file="pods/resource/cpu-request-limit.yaml" >}} {{< codenew file="pods/resource/cpu-request-limit.yaml" >}}
In the configuration file, the `args` section provides arguments for the Container when it starts. The `args` section of the configuration file provides arguments for the Container when it starts.
The `-cpus "2"` argument tells the Container to attempt to use 2 cpus. The `-cpus "2"` argument tells the Container to attempt to use 2 CPUs.
Create the Pod: Create the Pod:
@@ -82,7 +80,7 @@ Create the Pod:
kubectl create -f https://k8s.io/examples/pods/resource/cpu-request-limit.yaml --namespace=cpu-example kubectl create -f https://k8s.io/examples/pods/resource/cpu-request-limit.yaml --namespace=cpu-example
``` ```
Verify that the Pod's Container is running: Verify that the Pod Container is running:
```shell ```shell
kubectl get pod cpu-demo --namespace=cpu-example kubectl get pod cpu-demo --namespace=cpu-example
@@ -94,8 +92,8 @@ View detailed information about the Pod:
kubectl get pod cpu-demo --output=yaml --namespace=cpu-example kubectl get pod cpu-demo --output=yaml --namespace=cpu-example
``` ```
The output shows that the one Container in the Pod has a CPU request of 500 millicpu The output shows that the one Container in the Pod has a CPU request of 500 milliCPU
and a CPU limit of 1 cpu. and a CPU limit of 1 CPU.
```yaml ```yaml
resources: resources:
@@ -111,37 +109,35 @@ Use `kubectl top` to fetch the metrics for the pod:
kubectl top pod cpu-demo --namespace=cpu-example kubectl top pod cpu-demo --namespace=cpu-example
``` ```
The output shows that the Pod is using 974 millicpu, which is just a bit less than The output shows that the Pod is using 974 milliCPU, which is just a bit less than
the limit of 1 cpu specified in the Pod's configuration file. the limit of 1 CPU specified in the Pod configuration file.
``` ```
NAME CPU(cores) MEMORY(bytes) NAME CPU(cores) MEMORY(bytes)
cpu-demo 974m <something> cpu-demo 974m <something>
``` ```
Recall that by setting `-cpu "2"`, you configured the Container to attempt to use 2 cpus. Recall that by setting `-cpu "2"`, you configured the Container to attempt to use 2 CPUs, but the Container is only being allowed to use about 1 CPU. The Container CPU use is being throttled, because the Container is attempting to use more CPU resources than its limit.
But the Container is only being allowed to use about 1 cpu. The Container's CPU use is being
throttled, because the Container is attempting to use more CPU resources than its limit.
{{< note >}} {{< note >}}
**Note:** There's another possible explanation for the CPU throttling. The Node might not have **Note:** Another possible explanation for the CPU throttling is that the Node might not have
enough CPU resources available. Recall that the prerequisites for this exercise require that each of enough CPU resources available. Recall that the prerequisites for this exercise require each of
your Nodes has at least 1 cpu. If your Container is running on a Node that has only 1 cpu, the Container your Nodes ot have at least 1 CPU. If your Container runs on a Node that has only 1 CPU, the Container
cannot use more than 1 cpu regardless of the CPU limit specified for the Container. cannot use more than 1 CPU regardless of the CPU limit specified for the Container.
{{< /note >}} {{< /note >}}
## CPU units ## CPU units
The CPU resource is measured in *cpu* units. One cpu, in Kubernetes, is equivalent to: The CPU resource is measured in *CPU* units. One CPU, in Kubernetes, is equivalent to:
* 1 AWS vCPU * 1 AWS vCPU
* 1 GCP Core * 1 GCP Core
* 1 Azure vCore * 1 Azure vCore
* 1 Hyperthread on a bare-metal Intel processor with Hyperthreading * 1 Hyperthread on a bare-metal Intel processor with Hyperthreading
Fractional values are allowed. A Container that requests 0.5 cpu is guaranteed half as much Fractional values are allowed. A Container that requests 0.5 CPU is guaranteed half as much
CPU as a Container that requests 1 cpu. You can use the suffix m to mean milli. For example CPU as a Container that requests 1 CPU. You can use the suffix m to mean milli. For example
100m cpu, 100 millicpu, and 0.1 cpu are all the same. Precision finer than 1m is not allowed. 100m CPU, 100 milliCPU, and 0.1 CPU are all the same. Precision finer than 1m is not allowed.
CPU is always requested as an absolute quantity, never as a relative quantity; 0.1 is the same CPU is always requested as an absolute quantity, never as a relative quantity; 0.1 is the same
amount of CPU on a single-core, dual-core, or 48-core machine. amount of CPU on a single-core, dual-core, or 48-core machine.
@@ -160,11 +156,11 @@ of the CPU requests for all the Containers in the Pod. Likewise, the CPU limit f
a Pod is the sum of the CPU limits for all the Containers in the Pod. a Pod is the sum of the CPU limits for all the Containers in the Pod.
Pod scheduling is based on requests. A Pod is scheduled to run on a Node only if Pod scheduling is based on requests. A Pod is scheduled to run on a Node only if
the Node has enough CPU resources available to satisfy the Pod’s CPU request. the Node has enough CPU resources available to satisfy the Pod CPU request.
In this exercise, you create a Pod that has a CPU request so big that it exceeds In this exercise, you create a Pod that has a CPU request so big that it exceeds
the capacity of any Node in your cluster. Here is the configuration file for a Pod the capacity of any Node in your cluster. Here is the configuration file for a Pod
that has one Container. The Container requests 100 cpu, which is likely to exceed the that has one Container. The Container requests 100 CPU, which is likely to exceed the
capacity of any Node in your cluster. capacity of any Node in your cluster.
{{< codenew file="pods/resource/cpu-request-limit-2.yaml" >}} {{< codenew file="pods/resource/cpu-request-limit-2.yaml" >}}
@@ -175,13 +171,13 @@ Create the Pod:
kubectl create -f https://k8s.io/examples/pods/resource/cpu-request-limit-2.yaml --namespace=cpu-example kubectl create -f https://k8s.io/examples/pods/resource/cpu-request-limit-2.yaml --namespace=cpu-example
``` ```
View the Pod's status: View the Pod status:
```shell ```shell
kubectl get pod cpu-demo-2 --namespace=cpu-example kubectl get pod cpu-demo-2 --namespace=cpu-example
``` ```
The output shows that the Pod's status is Pending. That is, the Pod has not been The output shows that the Pod status is Pending. That is, the Pod has not been
scheduled to run on any Node, and it will remain in the Pending state indefinitely: scheduled to run on any Node, and it will remain in the Pending state indefinitely:
@@ -215,9 +211,9 @@ Delete your Pod:
kubectl delete pod cpu-demo-2 --namespace=cpu-example kubectl delete pod cpu-demo-2 --namespace=cpu-example
``` ```
## If you don’t specify a CPU limit ## If you do not specify a CPU limit
If you don’t specify a CPU limit for a Container, then one of these situations applies: If you do not specify a CPU limit for a Container, then one of these situations applies:
* The Container has no upper bound on the CPU resources it can use. The Container * The Container has no upper bound on the CPU resources it can use. The Container
could use all of the CPU resources available on the Node where it is running. could use all of the CPU resources available on the Node where it is running.
@@ -230,8 +226,8 @@ to specify a default value for the CPU limit.
## Motivation for CPU requests and limits ## Motivation for CPU requests and limits
By configuring the CPU requests and limits of the Containers that run in your By configuring the CPU requests and limits of the Containers that run in your
cluster, you can make efficient use of the CPU resources available on your cluster's cluster, you can make efficient use of the CPU resources available on your cluster
Nodes. By keeping a Pod's CPU request low, you give the Pod a good chance of being Nodes. By keeping a Pod CPU request low, you give the Pod a good chance of being
scheduled. By having a CPU limit that is greater than the CPU request, you accomplish two things: scheduled. By having a CPU limit that is greater than the CPU request, you accomplish two things:
* The Pod can have bursts of activity where it makes use of CPU resources that happen to be available. * The Pod can have bursts of activity where it makes use of CPU resources that happen to be available.