Resource quotas per project - Quotas | Building applications

Resources managed by quotas
Quota scopes
Quota enforcement
Requests versus limits
Sample resource quota definitions
Creating a quota
- Creating object count quotas
- Setting resource quota for extended resources
Viewing a quota
Configuring explicit resource quotas

A resource quota, defined by a ResourceQuota object, provides constraints that limit aggregate resource consumption per project. It can limit the quantity of objects that can be created in a project by type, as well as the total amount of compute resources and storage that might be consumed by resources in that project.

This guide describes how resource quotas work, how cluster administrators can set and manage resource quotas on a per project basis, and how developers and cluster administrators can view them.

Resources managed by quotas

The following describes the set of compute resources and object types that can be managed by a quota.

A pod is in a terminal state if status.phase in (Failed, Succeeded) is true.

Table 1. Compute resources managed by quota
Resource Name	Description
`cpu`	The sum of CPU requests across all pods in a non-terminal state cannot exceed this value. `cpu` and `requests.cpu` are the same value and can be used interchangeably.
`memory`	The sum of memory requests across all pods in a non-terminal state cannot exceed this value. `memory` and `requests.memory` are the same value and can be used interchangeably.
`requests.cpu`	The sum of CPU requests across all pods in a non-terminal state cannot exceed this value. `cpu` and `requests.cpu` are the same value and can be used interchangeably.
`requests.memory`	The sum of memory requests across all pods in a non-terminal state cannot exceed this value. `memory` and `requests.memory` are the same value and can be used interchangeably.
`limits.cpu`	The sum of CPU limits across all pods in a non-terminal state cannot exceed this value.
`limits.memory`	The sum of memory limits across all pods in a non-terminal state cannot exceed this value.

Table 2. Storage resources managed by quota
Resource Name	Description
`requests.storage`	The sum of storage requests across all persistent volume claims in any state cannot exceed this value.
`persistentvolumeclaims`	The total number of persistent volume claims that can exist in the project.
`<storage-class-name>.storageclass.storage.k8s.io/requests.storage`	The sum of storage requests across all persistent volume claims in any state that have a matching storage class, cannot exceed this value.
`<storage-class-name>.storageclass.storage.k8s.io/persistentvolumeclaims`	The total number of persistent volume claims with a matching storage class that can exist in the project.
`ephemeral-storage`	The sum of local ephemeral storage requests across all pods in a non-terminal state cannot exceed this value. `ephemeral-storage` and `requests.ephemeral-storage` are the same value and can be used interchangeably.
`requests.ephemeral-storage`	The sum of ephemeral storage requests across all pods in a non-terminal state cannot exceed this value. `ephemeral-storage` and `requests.ephemeral-storage` are the same value and can be used interchangeably.
`limits.ephemeral-storage`	The sum of ephemeral storage limits across all pods in a non-terminal state cannot exceed this value.

Table 3. Object counts managed by quota
Resource Name	Description
`pods`	The total number of pods in a non-terminal state that can exist in the project.
`replicationcontrollers`	The total number of ReplicationControllers that can exist in the project.
`resourcequotas`	The total number of resource quotas that can exist in the project.
`services`	The total number of services that can exist in the project.
`services.loadbalancers`	The total number of services of type `LoadBalancer` that can exist in the project.
`services.nodeports`	The total number of services of type `NodePort` that can exist in the project.
`secrets`	The total number of secrets that can exist in the project.
`configmaps`	The total number of `ConfigMap` objects that can exist in the project.
`persistentvolumeclaims`	The total number of persistent volume claims that can exist in the project.
`openshift.io/imagestreams`	The total number of imagestreams that can exist in the project.

Quota scopes

Each quota can have an associated set of scopes. A quota only measures usage for a resource if it matches the intersection of enumerated scopes.

Adding a scope to a quota restricts the set of resources to which that quota can apply. Specifying a resource outside of the allowed set results in a validation error.

Scope

Description

Terminating

Match pods where spec.activeDeadlineSeconds >= 0.

NotTerminating

Match pods where spec.activeDeadlineSeconds is nil.

BestEffort

Match pods that have best effort quality of service for either cpu or memory.

NotBestEffort

Match pods that do not have best effort quality of service for cpu and memory.

A BestEffort scope restricts a quota to limiting the following resources:

pods

A Terminating, NotTerminating, and NotBestEffort scope restricts a quota to tracking the following resources:

pods
memory
requests.memory
limits.memory
cpu
requests.cpu
limits.cpu

Quota enforcement

After a resource quota for a project is first created, the project restricts the ability to create any new resources that may violate a quota constraint until it has calculated updated usage statistics.

After a quota is created and usage statistics are updated, the project accepts the creation of new content. When you create or modify resources, your quota usage is incremented immediately upon the request to create or modify the resource.

When you delete a resource, your quota use is decremented during the next full recalculation of quota statistics for the project. A configurable amount of time determines how long it takes to reduce quota usage statistics to their current observed system value.

If project modifications exceed a quota usage limit, the server denies the action, and an appropriate error message is returned to the user explaining the quota constraint violated, and what their currently observed usage statistics are in the system.

Requests versus limits

When allocating compute resources, each container might specify a request and a limit value each for CPU, memory, and ephemeral storage. Quotas can restrict any of these values.

If the quota has a value specified for requests.cpu or requests.memory, then it requires that every incoming container make an explicit request for those resources. If the quota has a value specified for limits.cpu or limits.memory, then it requires that every incoming container specify an explicit limit for those resources.

Sample resource quota definitions

core-object-counts.yaml

apiVersion: v1
kind: ResourceQuota
metadata:
  name: core-object-counts
spec:
  hard:
    configmaps: "10" (1)
    persistentvolumeclaims: "4" (2)
    replicationcontrollers: "20" (3)
    secrets: "10" (4)
    services: "10" (5)
    services.loadbalancers: "2" (6)

1	The total number of `ConfigMap` objects that can exist in the project.
2	The total number of persistent volume claims (PVCs) that can exist in the project.
3	The total number of replication controllers that can exist in the project.
4	The total number of secrets that can exist in the project.
5	The total number of services that can exist in the project.
6	The total number of services of type `LoadBalancer` that can exist in the project.

openshift-object-counts.yaml

apiVersion: v1
kind: ResourceQuota
metadata:
  name: openshift-object-counts
spec:
  hard:
    openshift.io/imagestreams: "10" (1)

1	The total number of image streams that can exist in the project.

compute-resources.yaml

apiVersion: v1
kind: ResourceQuota
metadata:
  name: compute-resources
spec:
  hard:
    pods: "4" (1)
    requests.cpu: "1" (2)
    requests.memory: 1Gi (3)
    limits.cpu: "2" (4)
    limits.memory: 2Gi (5)

1	The total number of pods in a non-terminal state that can exist in the project.
2	Across all pods in a non-terminal state, the sum of CPU requests cannot exceed 1 core.
3	Across all pods in a non-terminal state, the sum of memory requests cannot exceed 1Gi.
4	Across all pods in a non-terminal state, the sum of CPU limits cannot exceed 2 cores.
5	Across all pods in a non-terminal state, the sum of memory limits cannot exceed 2Gi.

besteffort.yaml

apiVersion: v1
kind: ResourceQuota
metadata:
  name: besteffort
spec:
  hard:
    pods: "1" (1)
  scopes:
  - BestEffort (2)

1	The total number of pods in a non-terminal state with `BestEffort` quality of service that can exist in the project.
2	Restricts the quota to only matching pods that have `BestEffort` quality of service for either memory or CPU.

compute-resources-long-running.yaml

apiVersion: v1
kind: ResourceQuota
metadata:
  name: compute-resources-long-running
spec:
  hard:
    pods: "4" (1)
    limits.cpu: "4" (2)
    limits.memory: "2Gi" (3)
  scopes:
  - NotTerminating (4)

1	The total number of pods in a non-terminal state.
2	Across all pods in a non-terminal state, the sum of CPU limits cannot exceed this value.
3	Across all pods in a non-terminal state, the sum of memory limits cannot exceed this value.
4	Restricts the quota to only matching pods where `spec.activeDeadlineSeconds` is set to `nil`. Build pods fall under `NotTerminating` unless the `RestartNever` policy is applied.

compute-resources-time-bound.yaml

apiVersion: v1
kind: ResourceQuota
metadata:
  name: compute-resources-time-bound
spec:
  hard:
    pods: "2" (1)
    limits.cpu: "1" (2)
    limits.memory: "1Gi" (3)
  scopes:
  - Terminating (4)

1	The total number of pods in a terminating state.
2	Across all pods in a terminating state, the sum of CPU limits cannot exceed this value.
3	Across all pods in a terminating state, the sum of memory limits cannot exceed this value.
4	Restricts the quota to only matching pods where `spec.activeDeadlineSeconds >=0`. For example, this quota charges for build or deployer pods, but not long running pods like a web server or database.

storage-consumption.yaml

apiVersion: v1
kind: ResourceQuota
metadata:
  name: storage-consumption
spec:
  hard:
    persistentvolumeclaims: "10" (1)
    requests.storage: "50Gi" (2)
    gold.storageclass.storage.k8s.io/requests.storage: "10Gi" (3)
    silver.storageclass.storage.k8s.io/requests.storage: "20Gi" (4)
    silver.storageclass.storage.k8s.io/persistentvolumeclaims: "5" (5)
    bronze.storageclass.storage.k8s.io/requests.storage: "0" (6)
    bronze.storageclass.storage.k8s.io/persistentvolumeclaims: "0" (7)
    requests.ephemeral-storage: 2Gi (8)
    limits.ephemeral-storage: 4Gi (9)

1	The total number of persistent volume claims in a project
2	Across all persistent volume claims in a project, the sum of storage requested cannot exceed this value.
3	Across all persistent volume claims in a project, the sum of storage requested in the gold storage class cannot exceed this value.
4	Across all persistent volume claims in a project, the sum of storage requested in the silver storage class cannot exceed this value.
5	Across all persistent volume claims in a project, the total number of claims in the silver storage class cannot exceed this value.
6	Across all persistent volume claims in a project, the sum of storage requested in the bronze storage class cannot exceed this value. When this is set to `0`, it means bronze storage class cannot request storage.
7	Across all persistent volume claims in a project, the sum of storage requested in the bronze storage class cannot exceed this value. When this is set to `0`, it means bronze storage class cannot create claims.
8	Across all pods in a non-terminal state, the sum of ephemeral storage requests cannot exceed 2Gi.
9	Across all pods in a non-terminal state, the sum of ephemeral storage limits cannot exceed 4Gi.

Creating a quota

You can create a quota to constrain resource usage in a given project.

Procedure

Define the quota in a file.

Use the file to create the quota and apply it to a project:

$ oc create -f <file> [-n <project_name>]

For example:

$ oc create -f core-object-counts.yaml -n demoproject

Creating object count quotas

You can create an object count quota for all standard namespaced resource types on OpenShift Container Platform, such as BuildConfig and DeploymentConfig objects. An object quota count places a defined quota on all standard namespaced resource types.

When using a resource quota, an object is charged against the quota upon creation. These types of quotas are useful to protect against exhaustion of resources. The quota can only be created if there are enough spare resources within the project.

Procedure

To configure an object count quota for a resource:

Run the following command:
```
$ oc create quota <name> \
    --hard=count/<resource>.<group>=<quota>,count/<resource>.<group>=<quota> (1)
```
1 The <resource> variable is the name of the resource, and <group> is the API group, if applicable. Use the oc api-resources command for a list of resources and their associated API groups.

For example:
```
$ oc create quota test \
    --hard=count/deployments.extensions=2,count/replicasets.extensions=4,count/pods=3,count/secrets=4
```
Example output
```
resourcequota "test" created
```
This example limits the listed resources to the hard limit in each project in the cluster.

Verify that the quota was created:

$ oc describe quota test

Example output

Name:                         test
Namespace:                    quota
Resource                      Used  Hard
--------                      ----  ----
count/deployments.extensions  0     2
count/pods                    0     3
count/replicasets.extensions  0     4
count/secrets                 0     4

Setting resource quota for extended resources

Overcommitment of resources is not allowed for extended resources, so you must specify requests and limits for the same extended resource in a quota. Currently, only quota items with the prefix requests. is allowed for extended resources. The following is an example scenario of how to set resource quota for the GPU resource nvidia.com/gpu.

Procedure

Determine how many GPUs are available on a node in your cluster. For example:

# oc describe node ip-172-31-27-209.us-west-2.compute.internal | egrep 'Capacity|Allocatable|gpu'

Example output

                    openshift.com/gpu-accelerator=true
Capacity:
 nvidia.com/gpu:  2
Allocatable:
 nvidia.com/gpu:  2
  nvidia.com/gpu  0           0

In this example, 2 GPUs are available.