== Why is this an issue?

A CPU limitation for a container is a specified boundary or restriction that
determines the maximum amount of CPU resources that a container can utilize. It
is a part of resource management in a containerized environment, and it is set
to ensure that a single container does not monopolize the CPU resources of the
host machine.

CPU limitations are important for maintaining a balanced and efficient system.
They help in distributing resources fairly among different containers, ensuring
that no single container can cause a system-wide slowdown by consuming more than
its fair share of CPU resources.

=== What is the potential impact?

==== Performance degradation

Without CPU limitations, a single container could monopolize all available CPU
resources, leading to a system-wide slowdown. Other containers or processes on
the same host might be deprived of the necessary CPU resources, causing them to
function inefficiently.

==== System instability

In extreme cases, a container with no CPU limit could cause the host machine to
become unresponsive. This can lead to system downtime and potential loss of
data, disrupting critical operations and impacting system reliability.

== How to fix it

=== Code examples

==== Noncompliant code example

[source,yaml,diff-id=1,diff-type=noncompliant]
----
apiVersion: v1
kind: Pod
metadata:
  name: example
spec:
  containers:
    - name: web # Noncompliant
      image: nginx
----

==== Compliant solution

[source,yaml,diff-id=1,diff-type=compliant]
----
apiVersion: v1
kind: Pod
metadata:
  name: example
spec:
  containers:
    - name: web
      image: nginx
      resources:
        limits:
          cpu: 0.5
----

=== How does this work?

A limit can be set through the property `resources.limits.cpu` of a
container. Alternatively, a default limit for a namespace can be set with
`LimitRange`.

== Resources

=== Documentation

* Kubernetes Documentation - https://kubernetes.io/docs/concepts/configuration/manage-resources-containers/[Resource Management for Pods and Containers]

=== Standards

* CWE - https://cwe.mitre.org/data/definitions/770[CWE-770 - Allocation of Resources Without Limits or Throttling]


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Specify a CPU limit for this container.


=== Highlighting

* Highlight the key of the first child of the container that does not specify a CPU limit.


endif::env-github,rspecator-view[]
