Resource requests and limits in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a resource request in Kubernetes?

A resource request is the amount of CPU or memory that a container is guaranteed to have. Kubernetes uses this to decide which node can run the container.

beginner

What happens if a container exceeds its resource limit in Kubernetes?

If a container uses more CPU than its limit, Kubernetes throttles it. If it uses more memory than its limit, the container may be terminated (killed).

intermediate

Why should you set both resource requests and limits?

Setting requests ensures your container gets enough resources to run well. Limits prevent it from using too much and affecting other containers.

intermediate

How does Kubernetes use resource requests during scheduling?

Kubernetes checks the resource requests of a pod and finds a node with enough free resources to meet those requests before placing the pod there.

beginner

Give an example of setting CPU and memory requests and limits in a pod spec.

Example YAML snippet: resources: requests: memory: "128Mi" cpu: "250m" limits: memory: "256Mi" cpu: "500m"

What does a CPU request specify in Kubernetes?

A The CPU used by other containers

B The maximum CPU the container can use

C The total CPU of the node

D The minimum CPU guaranteed for the container

CPU request is the minimum CPU guaranteed to the container.

What happens if a container exceeds its memory limit?

A It is throttled

B It is terminated (killed)

C It continues running without limits

D It is moved to another node

Exceeding memory limit causes the container to be killed.

Why is it important to set resource limits?

A To prevent a container from using too many resources

B To speed up the container startup

C To guarantee unlimited resources

D To increase node capacity

Limits prevent containers from using excessive resources.

Which Kubernetes component uses resource requests to schedule pods?

A kubelet

B kube-proxy

C scheduler

D controller-manager

The scheduler uses resource requests to place pods on nodes.

In the resources section, what unit is '500m' CPU?

A 0.5 CPU (half a CPU)

B 500 CPUs

C 500 MHz CPU

D 500 MB CPU

'm' means milliCPU, so 500m is half a CPU.

Explain the difference between resource requests and limits in Kubernetes.

Think about what Kubernetes guarantees versus what it restricts.

Describe what happens when a container uses more CPU or memory than its limits.

Consider how Kubernetes controls resource usage to keep the system stable.