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Manage Memory, CPU, and API Resources
- 1: Configure Default Memory Requests and Limits for a Namespace
- 2: Configure Default CPU Requests and Limits for a Namespace
- 3: Configure Minimum and Maximum Memory Constraints for a Namespace
- 4: Configure Minimum and Maximum CPU Constraints for a Namespace
- 5: Configure Memory and CPU Quotas for a Namespace
- 6: Configure a Pod Quota for a Namespace
1 - Configure Default Memory Requests and Limits for a Namespace
This page shows how to configure default memory requests and limits for a namespace. If a Container is created in a namespace that has a default memory limit, and the Container does not specify its own memory limit, then the Container is assigned the default memory limit. Kubernetes assigns a default memory request under certain conditions that are explained later in this topic.
Before you begin
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:
To check the version, enterkubectl version
.
Each node in your cluster must have at least 2 GiB of memory.
Create a namespace
Create a namespace so that the resources you create in this exercise are isolated from the rest of your cluster.
kubectl create namespace default-mem-example
Create a LimitRange and a Pod
Here's the configuration file for a LimitRange object. The configuration specifies a default memory request and a default memory limit.
apiVersion: v1
kind: LimitRange
metadata:
name: mem-limit-range
spec:
limits:
- default:
memory: 512Mi
defaultRequest:
memory: 256Mi
type: Container
Create the LimitRange in the default-mem-example namespace:
kubectl apply -f https://k8s.io/examples/admin/resource/memory-defaults.yaml --namespace=default-mem-example
Now if a Container is created in the default-mem-example namespace, and the Container does not specify its own values for memory request and memory limit, the Container is given a default memory request of 256 MiB and a default memory limit of 512 MiB.
Here's the configuration file for a Pod that has one Container. The Container does not specify a memory request and limit.
apiVersion: v1
kind: Pod
metadata:
name: default-mem-demo
spec:
containers:
- name: default-mem-demo-ctr
image: nginx
Create the Pod.
kubectl apply -f https://k8s.io/examples/admin/resource/memory-defaults-pod.yaml --namespace=default-mem-example
View detailed information about the Pod:
kubectl get pod default-mem-demo --output=yaml --namespace=default-mem-example
The output shows that the Pod's Container has a memory request of 256 MiB and a memory limit of 512 MiB. These are the default values specified by the LimitRange.
containers:
- image: nginx
imagePullPolicy: Always
name: default-mem-demo-ctr
resources:
limits:
memory: 512Mi
requests:
memory: 256Mi
Delete your Pod:
kubectl delete pod default-mem-demo --namespace=default-mem-example
What if you specify a Container's limit, but not its request?
Here's the configuration file for a Pod that has one Container. The Container specifies a memory limit, but not a request:
apiVersion: v1
kind: Pod
metadata:
name: default-mem-demo-2
spec:
containers:
- name: default-mem-demo-2-ctr
image: nginx
resources:
limits:
memory: "1Gi"
Create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/memory-defaults-pod-2.yaml --namespace=default-mem-example
View detailed information about the Pod:
kubectl get pod default-mem-demo-2 --output=yaml --namespace=default-mem-example
The output shows that the Container's memory request is set to match its memory limit. Notice that the Container was not assigned the default memory request value of 256Mi.
resources:
limits:
memory: 1Gi
requests:
memory: 1Gi
What if you specify a Container's request, but not its limit?
Here's the configuration file for a Pod that has one Container. The Container specifies a memory request, but not a limit:
apiVersion: v1
kind: Pod
metadata:
name: default-mem-demo-3
spec:
containers:
- name: default-mem-demo-3-ctr
image: nginx
resources:
requests:
memory: "128Mi"
Create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/memory-defaults-pod-3.yaml --namespace=default-mem-example
View the Pod's specification:
kubectl get pod default-mem-demo-3 --output=yaml --namespace=default-mem-example
The output shows that the Container's memory request is set to the value specified in the Container's configuration file. The Container's memory limit is set to 512Mi, which is the default memory limit for the namespace.
resources:
limits:
memory: 512Mi
requests:
memory: 128Mi
Motivation for default memory limits and requests
If your namespace has a resource quota, it is helpful to have a default value in place for memory limit. Here are two of the restrictions that a resource quota imposes on a namespace:
- Every Container that runs in the namespace must have its own memory limit.
- The total amount of memory used by all Containers in the namespace must not exceed a specified limit.
If a Container does not specify its own memory limit, it is given the default limit, and then it can be allowed to run in a namespace that is restricted by a quota.
Clean up
Delete your namespace:
kubectl delete namespace default-mem-example
What's next
For cluster administrators
-
Configure Minimum and Maximum Memory Constraints for a Namespace
-
Configure Minimum and Maximum CPU Constraints for a Namespace
For app developers
2 - Configure Default CPU Requests and Limits for a Namespace
This page shows how to configure default CPU requests and limits for a namespace. A Kubernetes cluster can be divided into namespaces. If a Container is created in a namespace that has a default CPU limit, and the Container does not specify its own CPU limit, then the Container is assigned the default CPU limit. Kubernetes assigns a default CPU request under certain conditions that are explained later in this topic.
Before you begin
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:
To check the version, enterkubectl version
.
Create a namespace
Create a namespace so that the resources you create in this exercise are isolated from the rest of your cluster.
kubectl create namespace default-cpu-example
Create a LimitRange and a Pod
Here's the configuration file for a LimitRange object. The configuration specifies a default CPU request and a default CPU limit.
apiVersion: v1
kind: LimitRange
metadata:
name: cpu-limit-range
spec:
limits:
- default:
cpu: 1
defaultRequest:
cpu: 0.5
type: Container
Create the LimitRange in the default-cpu-example namespace:
kubectl apply -f https://k8s.io/examples/admin/resource/cpu-defaults.yaml --namespace=default-cpu-example
Now if a Container is created in the default-cpu-example namespace, and the Container does not specify its own values for CPU request and CPU limit, the Container is given a default CPU request of 0.5 and a default CPU limit of 1.
Here's the configuration file for a Pod that has one Container. The Container does not specify a CPU request and limit.
apiVersion: v1
kind: Pod
metadata:
name: default-cpu-demo
spec:
containers:
- name: default-cpu-demo-ctr
image: nginx
Create the Pod.
kubectl apply -f https://k8s.io/examples/admin/resource/cpu-defaults-pod.yaml --namespace=default-cpu-example
View the Pod's specification:
kubectl get pod default-cpu-demo --output=yaml --namespace=default-cpu-example
The output shows that the Pod's Container has a CPU request of 500 millicpus and a CPU limit of 1 cpu. These are the default values specified by the LimitRange.
containers:
- image: nginx
imagePullPolicy: Always
name: default-cpu-demo-ctr
resources:
limits:
cpu: "1"
requests:
cpu: 500m
What if you specify a Container's limit, but not its request?
Here's the configuration file for a Pod that has one Container. The Container specifies a CPU limit, but not a request:
apiVersion: v1
kind: Pod
metadata:
name: default-cpu-demo-2
spec:
containers:
- name: default-cpu-demo-2-ctr
image: nginx
resources:
limits:
cpu: "1"
Create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/cpu-defaults-pod-2.yaml --namespace=default-cpu-example
View the Pod specification:
kubectl get pod default-cpu-demo-2 --output=yaml --namespace=default-cpu-example
The output shows that the Container's CPU request is set to match its CPU limit. Notice that the Container was not assigned the default CPU request value of 0.5 cpu.
resources:
limits:
cpu: "1"
requests:
cpu: "1"
What if you specify a Container's request, but not its limit?
Here's the configuration file for a Pod that has one Container. The Container specifies a CPU request, but not a limit:
apiVersion: v1
kind: Pod
metadata:
name: default-cpu-demo-3
spec:
containers:
- name: default-cpu-demo-3-ctr
image: nginx
resources:
requests:
cpu: "0.75"
Create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/cpu-defaults-pod-3.yaml --namespace=default-cpu-example
View the Pod specification:
kubectl get pod default-cpu-demo-3 --output=yaml --namespace=default-cpu-example
The output shows that the Container's CPU request is set to the value specified in the Container's configuration file. The Container's CPU limit is set to 1 cpu, which is the default CPU limit for the namespace.
resources:
limits:
cpu: "1"
requests:
cpu: 750m
Motivation for default CPU limits and requests
If your namespace has a resource quota, it is helpful to have a default value in place for CPU limit. Here are two of the restrictions that a resource quota imposes on a namespace:
- Every Container that runs in the namespace must have its own CPU limit.
- The total amount of CPU used by all Containers in the namespace must not exceed a specified limit.
If a Container does not specify its own CPU limit, it is given the default limit, and then it can be allowed to run in a namespace that is restricted by a quota.
Clean up
Delete your namespace:
kubectl delete namespace default-cpu-example
What's next
For cluster administrators
-
Configure Default Memory Requests and Limits for a Namespace
-
Configure Minimum and Maximum Memory Constraints for a Namespace
-
Configure Minimum and Maximum CPU Constraints for a Namespace
For app developers
3 - Configure Minimum and Maximum Memory Constraints for a Namespace
This page shows how to set minimum and maximum values for memory used by Containers running in a namespace. You specify minimum and maximum memory values in a LimitRange object. If a Pod does not meet the constraints imposed by the LimitRange, it cannot be created in the namespace.
Before you begin
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:
To check the version, enterkubectl version
.
Each node in your cluster must have at least 1 GiB of memory.
Create a namespace
Create a namespace so that the resources you create in this exercise are isolated from the rest of your cluster.
kubectl create namespace constraints-mem-example
Create a LimitRange and a Pod
Here's the configuration file for a LimitRange:
apiVersion: v1
kind: LimitRange
metadata:
name: mem-min-max-demo-lr
spec:
limits:
- max:
memory: 1Gi
min:
memory: 500Mi
type: Container
Create the LimitRange:
kubectl apply -f https://k8s.io/examples/admin/resource/memory-constraints.yaml --namespace=constraints-mem-example
View detailed information about the LimitRange:
kubectl get limitrange mem-min-max-demo-lr --namespace=constraints-mem-example --output=yaml
The output shows the minimum and maximum memory constraints as expected. But notice that even though you didn't specify default values in the configuration file for the LimitRange, they were created automatically.
limits:
- default:
memory: 1Gi
defaultRequest:
memory: 1Gi
max:
memory: 1Gi
min:
memory: 500Mi
type: Container
Now whenever a Container is created in the constraints-mem-example namespace, Kubernetes performs these steps:
-
If the Container does not specify its own memory request and limit, assign the default memory request and limit to the Container.
-
Verify that the Container has a memory request that is greater than or equal to 500 MiB.
-
Verify that the Container has a memory limit that is less than or equal to 1 GiB.
Here's the configuration file for a Pod that has one Container. The Container manifest specifies a memory request of 600 MiB and a memory limit of 800 MiB. These satisfy the minimum and maximum memory constraints imposed by the LimitRange.
apiVersion: v1
kind: Pod
metadata:
name: constraints-mem-demo
spec:
containers:
- name: constraints-mem-demo-ctr
image: nginx
resources:
limits:
memory: "800Mi"
requests:
memory: "600Mi"
Create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/memory-constraints-pod.yaml --namespace=constraints-mem-example
Verify that the Pod's Container is running:
kubectl get pod constraints-mem-demo --namespace=constraints-mem-example
View detailed information about the Pod:
kubectl get pod constraints-mem-demo --output=yaml --namespace=constraints-mem-example
The output shows that the Container has a memory request of 600 MiB and a memory limit of 800 MiB. These satisfy the constraints imposed by the LimitRange.
resources:
limits:
memory: 800Mi
requests:
memory: 600Mi
Delete your Pod:
kubectl delete pod constraints-mem-demo --namespace=constraints-mem-example
Attempt to create a Pod that exceeds the maximum memory constraint
Here's the configuration file for a Pod that has one Container. The Container specifies a memory request of 800 MiB and a memory limit of 1.5 GiB.
apiVersion: v1
kind: Pod
metadata:
name: constraints-mem-demo-2
spec:
containers:
- name: constraints-mem-demo-2-ctr
image: nginx
resources:
limits:
memory: "1.5Gi"
requests:
memory: "800Mi"
Attempt to create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/memory-constraints-pod-2.yaml --namespace=constraints-mem-example
The output shows that the Pod does not get created, because the Container specifies a memory limit that is too large:
Error from server (Forbidden): error when creating "examples/admin/resource/memory-constraints-pod-2.yaml":
pods "constraints-mem-demo-2" is forbidden: maximum memory usage per Container is 1Gi, but limit is 1536Mi.
Attempt to create a Pod that does not meet the minimum memory request
Here's the configuration file for a Pod that has one Container. The Container specifies a memory request of 100 MiB and a memory limit of 800 MiB.
apiVersion: v1
kind: Pod
metadata:
name: constraints-mem-demo-3
spec:
containers:
- name: constraints-mem-demo-3-ctr
image: nginx
resources:
limits:
memory: "800Mi"
requests:
memory: "100Mi"
Attempt to create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/memory-constraints-pod-3.yaml --namespace=constraints-mem-example
The output shows that the Pod does not get created, because the Container specifies a memory request that is too small:
Error from server (Forbidden): error when creating "examples/admin/resource/memory-constraints-pod-3.yaml":
pods "constraints-mem-demo-3" is forbidden: minimum memory usage per Container is 500Mi, but request is 100Mi.
Create a Pod that does not specify any memory request or limit
Here's the configuration file for a Pod that has one Container. The Container does not specify a memory request, and it does not specify a memory limit.
apiVersion: v1
kind: Pod
metadata:
name: constraints-mem-demo-4
spec:
containers:
- name: constraints-mem-demo-4-ctr
image: nginx
Create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/memory-constraints-pod-4.yaml --namespace=constraints-mem-example
View detailed information about the Pod:
kubectl get pod constraints-mem-demo-4 --namespace=constraints-mem-example --output=yaml
The output shows that the Pod's Container has a memory request of 1 GiB and a memory limit of 1 GiB. How did the Container get those values?
resources:
limits:
memory: 1Gi
requests:
memory: 1Gi
Because your Container did not specify its own memory request and limit, it was given the default memory request and limit from the LimitRange.
At this point, your Container might be running or it might not be running. Recall that a prerequisite for this task is that your Nodes have at least 1 GiB of memory. If each of your Nodes has only 1 GiB of memory, then there is not enough allocatable memory on any Node to accommodate a memory request of 1 GiB. If you happen to be using Nodes with 2 GiB of memory, then you probably have enough space to accommodate the 1 GiB request.
Delete your Pod:
kubectl delete pod constraints-mem-demo-4 --namespace=constraints-mem-example
Enforcement of minimum and maximum memory constraints
The maximum and minimum memory constraints imposed on a namespace by a LimitRange are enforced only when a Pod is created or updated. If you change the LimitRange, it does not affect Pods that were created previously.
Motivation for minimum and maximum memory constraints
As a cluster administrator, you might want to impose restrictions on the amount of memory that Pods can use. For example:
-
Each Node in a cluster has 2 GB of memory. You do not want to accept any Pod that requests more than 2 GB of memory, because no Node in the cluster can support the request.
-
A cluster is shared by your production and development departments. You want to allow production workloads to consume up to 8 GB of memory, but you want development workloads to be limited to 512 MB. You create separate namespaces for production and development, and you apply memory constraints to each namespace.
Clean up
Delete your namespace:
kubectl delete namespace constraints-mem-example
What's next
For cluster administrators
-
Configure Default Memory Requests and Limits for a Namespace
-
Configure Minimum and Maximum CPU Constraints for a Namespace
For app developers
4 - Configure Minimum and Maximum CPU Constraints for a Namespace
This page shows how to set minimum and maximum values for the CPU resources used by Containers and Pods in a namespace. You specify minimum and maximum CPU values in a LimitRange object. If a Pod does not meet the constraints imposed by the LimitRange, it cannot be created in the namespace.
Before you begin
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:
To check the version, enterkubectl version
.
Your cluster must have at least 1 CPU available for use to run the task examples.
Create a namespace
Create a namespace so that the resources you create in this exercise are isolated from the rest of your cluster.
kubectl create namespace constraints-cpu-example
Create a LimitRange and a Pod
Here's the configuration file for a LimitRange:
apiVersion: v1
kind: LimitRange
metadata:
name: cpu-min-max-demo-lr
spec:
limits:
- max:
cpu: "800m"
min:
cpu: "200m"
type: Container
Create the LimitRange:
kubectl apply -f https://k8s.io/examples/admin/resource/cpu-constraints.yaml --namespace=constraints-cpu-example
View detailed information about the LimitRange:
kubectl get limitrange cpu-min-max-demo-lr --output=yaml --namespace=constraints-cpu-example
The output shows the minimum and maximum CPU constraints as expected. But notice that even though you didn't specify default values in the configuration file for the LimitRange, they were created automatically.
limits:
- default:
cpu: 800m
defaultRequest:
cpu: 800m
max:
cpu: 800m
min:
cpu: 200m
type: Container
Now whenever a Container is created in the constraints-cpu-example namespace, Kubernetes performs these steps:
-
If the Container does not specify its own CPU request and limit, assign the default CPU request and limit to the Container.
-
Verify that the Container specifies a CPU request that is greater than or equal to 200 millicpu.
-
Verify that the Container specifies a CPU limit that is less than or equal to 800 millicpu.
LimitRange
object, you can specify limits on huge-pages
or GPUs as well. However, when both default
and defaultRequest
are specified
on these resources, the two values must be the same.
Here's the configuration file for a Pod that has one Container. The Container manifest specifies a CPU request of 500 millicpu and a CPU limit of 800 millicpu. These satisfy the minimum and maximum CPU constraints imposed by the LimitRange.
apiVersion: v1
kind: Pod
metadata:
name: constraints-cpu-demo
spec:
containers:
- name: constraints-cpu-demo-ctr
image: nginx
resources:
limits:
cpu: "800m"
requests:
cpu: "500m"
Create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/cpu-constraints-pod.yaml --namespace=constraints-cpu-example
Verify that the Pod's Container is running:
kubectl get pod constraints-cpu-demo --namespace=constraints-cpu-example
View detailed information about the Pod:
kubectl get pod constraints-cpu-demo --output=yaml --namespace=constraints-cpu-example
The output shows that the Container has a CPU request of 500 millicpu and CPU limit of 800 millicpu. These satisfy the constraints imposed by the LimitRange.
resources:
limits:
cpu: 800m
requests:
cpu: 500m
Delete the Pod
kubectl delete pod constraints-cpu-demo --namespace=constraints-cpu-example
Attempt to create a Pod that exceeds the maximum CPU constraint
Here's the configuration file for a Pod that has one Container. The Container specifies a CPU request of 500 millicpu and a cpu limit of 1.5 cpu.
apiVersion: v1
kind: Pod
metadata:
name: constraints-cpu-demo-2
spec:
containers:
- name: constraints-cpu-demo-2-ctr
image: nginx
resources:
limits:
cpu: "1.5"
requests:
cpu: "500m"
Attempt to create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/cpu-constraints-pod-2.yaml --namespace=constraints-cpu-example
The output shows that the Pod does not get created, because the Container specifies a CPU limit that is too large:
Error from server (Forbidden): error when creating "examples/admin/resource/cpu-constraints-pod-2.yaml":
pods "constraints-cpu-demo-2" is forbidden: maximum cpu usage per Container is 800m, but limit is 1500m.
Attempt to create a Pod that does not meet the minimum CPU request
Here's the configuration file for a Pod that has one Container. The Container specifies a CPU request of 100 millicpu and a CPU limit of 800 millicpu.
apiVersion: v1
kind: Pod
metadata:
name: constraints-cpu-demo-3
spec:
containers:
- name: constraints-cpu-demo-3-ctr
image: nginx
resources:
limits:
cpu: "800m"
requests:
cpu: "100m"
Attempt to create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/cpu-constraints-pod-3.yaml --namespace=constraints-cpu-example
The output shows that the Pod does not get created, because the Container specifies a CPU request that is too small:
Error from server (Forbidden): error when creating "examples/admin/resource/cpu-constraints-pod-3.yaml":
pods "constraints-cpu-demo-3" is forbidden: minimum cpu usage per Container is 200m, but request is 100m.
Create a Pod that does not specify any CPU request or limit
Here's the configuration file for a Pod that has one Container. The Container does not specify a CPU request, and it does not specify a CPU limit.
apiVersion: v1
kind: Pod
metadata:
name: constraints-cpu-demo-4
spec:
containers:
- name: constraints-cpu-demo-4-ctr
image: vish/stress
Create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/cpu-constraints-pod-4.yaml --namespace=constraints-cpu-example
View detailed information about the Pod:
kubectl get pod constraints-cpu-demo-4 --namespace=constraints-cpu-example --output=yaml
The output shows that the Pod's Container has a CPU request of 800 millicpu and a CPU limit of 800 millicpu. How did the Container get those values?
resources:
limits:
cpu: 800m
requests:
cpu: 800m
Because your Container did not specify its own CPU request and limit, it was given the default CPU request and limit from the LimitRange.
At this point, your Container might be running or it might not be running. Recall that a prerequisite for this task is that your cluster must have at least 1 CPU available for use. If each of your Nodes has only 1 CPU, then there might not be enough allocatable CPU on any Node to accommodate a request of 800 millicpu. If you happen to be using Nodes with 2 CPU, then you probably have enough CPU to accommodate the 800 millicpu request.
Delete your Pod:
kubectl delete pod constraints-cpu-demo-4 --namespace=constraints-cpu-example
Enforcement of minimum and maximum CPU constraints
The maximum and minimum CPU constraints imposed on a namespace by a LimitRange are enforced only when a Pod is created or updated. If you change the LimitRange, it does not affect Pods that were created previously.
Motivation for minimum and maximum CPU constraints
As a cluster administrator, you might want to impose restrictions on the CPU resources that Pods can use. For example:
-
Each Node in a cluster has 2 CPU. You do not want to accept any Pod that requests more than 2 CPU, because no Node in the cluster can support the request.
-
A cluster is shared by your production and development departments. You want to allow production workloads to consume up to 3 CPU, but you want development workloads to be limited to 1 CPU. You create separate namespaces for production and development, and you apply CPU constraints to each namespace.
Clean up
Delete your namespace:
kubectl delete namespace constraints-cpu-example
What's next
For cluster administrators
-
Configure Default Memory Requests and Limits for a Namespace
-
Configure Minimum and Maximum Memory Constraints for a Namespace
For app developers
5 - Configure Memory and CPU Quotas for a Namespace
This page shows how to set quotas for the total amount memory and CPU that can be used by all Containers running in a namespace. You specify quotas in a ResourceQuota object.
Before you begin
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:
To check the version, enterkubectl version
.
Each node in your cluster must have at least 1 GiB of memory.
Create a namespace
Create a namespace so that the resources you create in this exercise are isolated from the rest of your cluster.
kubectl create namespace quota-mem-cpu-example
Create a ResourceQuota
Here is the configuration file for a ResourceQuota object:
apiVersion: v1
kind: ResourceQuota
metadata:
name: mem-cpu-demo
spec:
hard:
requests.cpu: "1"
requests.memory: 1Gi
limits.cpu: "2"
limits.memory: 2Gi
Create the ResourceQuota:
kubectl apply -f https://k8s.io/examples/admin/resource/quota-mem-cpu.yaml --namespace=quota-mem-cpu-example
View detailed information about the ResourceQuota:
kubectl get resourcequota mem-cpu-demo --namespace=quota-mem-cpu-example --output=yaml
The ResourceQuota places these requirements on the quota-mem-cpu-example namespace:
- Every Container must have a memory request, memory limit, cpu request, and cpu limit.
- The memory request total for all Containers must not exceed 1 GiB.
- The memory limit total for all Containers must not exceed 2 GiB.
- The CPU request total for all Containers must not exceed 1 cpu.
- The CPU limit total for all Containers must not exceed 2 cpu.
Create a Pod
Here is the configuration file for a Pod:
apiVersion: v1
kind: Pod
metadata:
name: quota-mem-cpu-demo
spec:
containers:
- name: quota-mem-cpu-demo-ctr
image: nginx
resources:
limits:
memory: "800Mi"
cpu: "800m"
requests:
memory: "600Mi"
cpu: "400m"
Create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/quota-mem-cpu-pod.yaml --namespace=quota-mem-cpu-example
Verify that the Pod's Container is running:
kubectl get pod quota-mem-cpu-demo --namespace=quota-mem-cpu-example
Once again, view detailed information about the ResourceQuota:
kubectl get resourcequota mem-cpu-demo --namespace=quota-mem-cpu-example --output=yaml
The output shows the quota along with how much of the quota has been used. You can see that the memory and CPU requests and limits for your Pod do not exceed the quota.
status:
hard:
limits.cpu: "2"
limits.memory: 2Gi
requests.cpu: "1"
requests.memory: 1Gi
used:
limits.cpu: 800m
limits.memory: 800Mi
requests.cpu: 400m
requests.memory: 600Mi
Attempt to create a second Pod
Here is the configuration file for a second Pod:
apiVersion: v1
kind: Pod
metadata:
name: quota-mem-cpu-demo-2
spec:
containers:
- name: quota-mem-cpu-demo-2-ctr
image: redis
resources:
limits:
memory: "1Gi"
cpu: "800m"
requests:
memory: "700Mi"
cpu: "400m"
In the configuration file, you can see that the Pod has a memory request of 700 MiB. Notice that the sum of the used memory request and this new memory request exceeds the memory request quota. 600 MiB + 700 MiB > 1 GiB.
Attempt to create the Pod:
kubectl apply -f https://k8s.io/examples/admin/resource/quota-mem-cpu-pod-2.yaml --namespace=quota-mem-cpu-example
The second Pod does not get created. The output shows that creating the second Pod would cause the memory request total to exceed the memory request quota.
Error from server (Forbidden): error when creating "examples/admin/resource/quota-mem-cpu-pod-2.yaml":
pods "quota-mem-cpu-demo-2" is forbidden: exceeded quota: mem-cpu-demo,
requested: requests.memory=700Mi,used: requests.memory=600Mi, limited: requests.memory=1Gi
Discussion
As you have seen in this exercise, you can use a ResourceQuota to restrict the memory request total for all Containers running in a namespace. You can also restrict the totals for memory limit, cpu request, and cpu limit.
If you want to restrict individual Containers, instead of totals for all Containers, use a LimitRange.
Clean up
Delete your namespace:
kubectl delete namespace quota-mem-cpu-example
What's next
For cluster administrators
-
Configure Default Memory Requests and Limits for a Namespace
-
Configure Minimum and Maximum Memory Constraints for a Namespace
-
Configure Minimum and Maximum CPU Constraints for a Namespace
For app developers
6 - Configure a Pod Quota for a Namespace
This page shows how to set a quota for the total number of Pods that can run in a namespace. You specify quotas in a ResourceQuota object.
Before you begin
You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:
To check the version, enterkubectl version
.
Create a namespace
Create a namespace so that the resources you create in this exercise are isolated from the rest of your cluster.
kubectl create namespace quota-pod-example
Create a ResourceQuota
Here is the configuration file for a ResourceQuota object:
apiVersion: v1
kind: ResourceQuota
metadata:
name: pod-demo
spec:
hard:
pods: "2"
Create the ResourceQuota:
kubectl apply -f https://k8s.io/examples/admin/resource/quota-pod.yaml --namespace=quota-pod-example
View detailed information about the ResourceQuota:
kubectl get resourcequota pod-demo --namespace=quota-pod-example --output=yaml
The output shows that the namespace has a quota of two Pods, and that currently there are no Pods; that is, none of the quota is used.
spec:
hard:
pods: "2"
status:
hard:
pods: "2"
used:
pods: "0"
Here is the configuration file for a Deployment:
apiVersion: apps/v1
kind: Deployment
metadata:
name: pod-quota-demo
spec:
selector:
matchLabels:
purpose: quota-demo
replicas: 3
template:
metadata:
labels:
purpose: quota-demo
spec:
containers:
- name: pod-quota-demo
image: nginx
In the configuration file, replicas: 3
tells Kubernetes to attempt to create three Pods, all running the same application.
Create the Deployment:
kubectl apply -f https://k8s.io/examples/admin/resource/quota-pod-deployment.yaml --namespace=quota-pod-example
View detailed information about the Deployment:
kubectl get deployment pod-quota-demo --namespace=quota-pod-example --output=yaml
The output shows that even though the Deployment specifies three replicas, only two Pods were created because of the quota.
spec:
...
replicas: 3
...
status:
availableReplicas: 2
...
lastUpdateTime: 2017-07-07T20:57:05Z
message: 'unable to create pods: pods "pod-quota-demo-1650323038-" is forbidden:
exceeded quota: pod-demo, requested: pods=1, used: pods=2, limited: pods=2'
Clean up
Delete your namespace:
kubectl delete namespace quota-pod-example
What's next
For cluster administrators
-
Configure Default Memory Requests and Limits for a Namespace
-
Configure Minimum and Maximum Memory Constraints for a Namespace
-
Configure Minimum and Maximum CPU Constraints for a Namespace