What are resource requests and limits in Kubernetes?

In Kubernetes, resource requests and limits are used to manage the resources allocated to containers within a pod. Here's a brief explanation of each:

Resource Requests

• Definition: The minimum amount of CPU and memory that a container is guaranteed to have.
• Purpose: Ensures that the container has enough resources to run effectively. If the node where the pod is scheduled does not have enough resources to meet the requests, the pod will not be scheduled on that node.

Resource Limits

• Definition: The maximum amount of CPU and memory that a container is allowed to use.
• Purpose: Prevents a container from consuming excessive resources, which could affect other containers running on the same node. If a container tries to use more than its limit, it may be throttled (for CPU) or terminated (for memory).

Example

When defining a deployment, you can specify requests and limits like this:

resources:
  requests:
    cpu: "500m"      # 0.5 CPU
    memory: "256Mi"  # 256 MiB
  limits:
    cpu: "1"         # 1 CPU
    memory: "512Mi"  # 512 MiB

This configuration ensures that the container has a guaranteed minimum of 0.5 CPU and 256 MiB of memory, while capping its usage at 1 CPU and 512 MiB of memory.

If you have more questions or need further clarification, feel free to ask!