Code change:
<ins> Resource Quota ======================================== This example demonstrates how resource quota and limits can be applied to a Kubernetes namespace. This example assumes you have a functional Kubernetes setup. Step 1: Create a namespace ----------------------------------------- This example will work in a custom namespace to demonstrate the concepts involved. Let's create a new namespace called quota-example: ```shell $ cluster/kubectl.sh create -f namespace.yaml $ cluster/kubectl.sh get namespaces NAME            LABELS             STATUS default         <none>             Active quota-example   <none>             Active ``` Step 2: Apply a quota to the namespace ----------------------------------------- By default, a pod will run with unbounded CPU and memory limits.  This means that any pod in the system will be able to consume as much CPU and memory on the node that executes the pod. Users may want to restrict how much of the cluster resources a given namespace may consume across all of its pods in order to manage cluster usage.  To do this, a user applies a quota to a namespace.  A quota lets the user set hard limits on the total amount of node resources (cpu, memory) and API resources (pods, services, etc.) that a namespace may consume. Let's create a simple quota in our namespace: ```shell $ cluster/kubectl.sh create -f quota.yaml --namespace=quota-example ``` Once your quota is applied to a namespace, the system will restrict any creation of content in the namespace until the quota usage has been calculated.  This should happen quickly. You can describe your current quota usage to see what resources are being consumed in your namespace. ``` $ cluster/kubectl.sh describe quota quota --namespace=quota-example Name:     quota Resource    Used  Hard --------    ----  ---- cpu     0m  20 memory      0m  1Gi persistentvolumeclaims  0m  10 pods      0m  10 replicationcontrollers  0m  20 resourcequotas    1 1 secrets     1 10 services    0m  5 ``` Step 3: Applying default resource limits ----------------------------------------- Pod authors rarely specify resource limits for their pods. Since we applied a quota to our project, let's see what happens when an end-user creates a pod that has unbounded cpu and memory by creating an nginx container. To demonstrate, lets create a replication controller that runs nginx: ```shell $ cluster/kubectl.sh run nginx --image=nginx --replicas=1 --namespace=quota-example CONTROLLER   CONTAINER(S)   IMAGE(S)   SELECTOR    REPLICAS nginx        nginx          nginx      run=nginx   1 ``` Now let's look at the pods that were created. ```shell $ cluster/kubectl.sh get pods --namespace=quota-example POD       IP        CONTAINER(S)   IMAGE(S)   HOST      LABELS    STATUS    CREATED   MESSAGE ``` What happened?  I have no pods!  Let's describe the replication controller to get a view of what is happening. ```shell cluster/kubectl.sh describe rc nginx --namespace=quota-example Name:   nginx Image(s): nginx Selector: run=nginx Labels:   run=nginx Replicas: 0 current / 1 desired Pods Status:  0 Running / 0 Waiting / 0 Succeeded / 0 Failed Events: FirstSeen       LastSeen      Count From        SubobjectPath Reason    Message Mon, 01 Jun 2015 22:49:31 -0400 Mon, 01 Jun 2015 22:52:22 -0400 7 {replication-controller }     failedCreate  Error creating: Pod "nginx-" is forbidden: Limited to 1Gi memory, but pod has no specified memory limit ``` The Kubernetes API server is rejecting the replication controllers requests to create a pod because our pods do not specify any memory usage. So let's set some default limits for the amount of cpu and memory a pod can consume: ```shell $ cluster/kubectl.sh create -f limits.yaml --namespace=quota-example limitranges/limits $ cluster/kubectl.sh describe limits limits --namespace=quota-example Name:   limits Type    Resource  Min Max Default ----    --------  --- --- --- Container cpu   - - 100m Container memory    - - 512Mi ``` Now any time a pod is created in this namespace, if it has not specified any resource limits, the default amount of cpu and memory per container will be applied as part of admission control. Now that we have applied default limits for our namespace, our replication controller should be able to create its pods. ```shell $ cluster/kubectl.sh get pods --namespace=quota-example POD           IP         CONTAINER(S)   IMAGE(S)   HOST                    LABELS      STATUS    CREATED     MESSAGE nginx-t40zm   10.0.0.2                             10.245.1.3/10.245.1.3   run=nginx   Running   2 minutes nginx          nginx                                          Running   2 minutes ``` And if we print out our quota usage in the namespace: ```shell cluster/kubectl.sh describe quota quota --namespace=quota-example Name:     quota Resource    Used    Hard --------    ----    ---- cpu     100m    20 memory      536870912 1Gi persistentvolumeclaims  0m    10 pods      1   10 replicationcontrollers  1   20 resourcequotas    1   1 secrets     1   10 services    0m    5 ``` You can now see the pod that was created is consuming explicit amounts of resources, and the usage is being tracked by the Kubernetes system properly. Summary ---------------------------- Actions that consume node resources for cpu and memory can be subject to hard quota limits defined by the namespace quota. Any action that consumes those resources can be tweaked, or can pick up namespace level defaults to meet your end goal. [![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/examples/resourcequota/README.md?pixel)]() </ins>

Related discussion:
text: Resource quota example is missing readme. Was it once there and was accidentally deleted?
I wrote something up in Origin repo I need to repurpose for Kubernetes. Sent from my iPhone