Kube-Score - Kubernetes Object Analysis With Recommendations For Improved Reliability And Security

Kube-Score – Kubernetes Object Analysis With Recommendations For Improved Reliability And Security

kube-score is a tool that performs static code analysis of your Kubernetes object definitions.

The output is a list of recommendations of what you can improve to make your application more secure and resilient.

You can test kube-score out in the browser with the online demo (source).

Installation

kube-score is easy to install, and is available from the following sources:

DistributionCommand / Link
Pre-built binaries for macOS, Linux, and WindowsGitHub releases
Dockerdocker pull zegl/kube-score (Docker Hub)
Homebrew (macOS and Linux)brew install kube-score/tap/kube-score
Krew (macOS and Linux)kubectl krew install score

Checks

For a full list of checks, see README_CHECKS.md.

  • Container limits (should be set)
  • Pod is targeted by a NetworkPolicy, both egress and ingress rules are recommended
  • Deployments and StatefulSets should have a PodDisruptionPolicy
  • Deployments and StatefulSets should have host PodAntiAffinity configured
  • Container probes, a readiness should be configured, and should not be identical to the liveness probe. Read more in README_PROBES.md.
  • Container securityContext, run as high number user/group, do not run as root or with privileged root fs
  • Stable APIs, use a stable API if available (supported: Deployments, StatefulSets, DaemonSet)

Example output

Usage in CI

kube-score can run in your CI/CD environment and will exit with exit code 1 if a critical error has been found. The trigger level can be changed to warning with the --exit-one-on-warning argument.

The input to kube-score should be all applications that you deploy to the same namespace for the best result.

Example with Helm

helm template my-app | kube-score score -

Example with Kustomize

kustomize build . | kube-score score -

Example with static YAMLs

kube-score score my-app/*.yaml
kube-score score my-app/deployment.yaml my-app/service.yaml

Example with an existing cluster

kubectl api-resources --verbs=list --namespaced -o name 
| xargs -n1 -I{} bash -c "kubectl get {} --all-namespaces -oyaml && echo ---"
| kube-score score -

Example with Docker

docker run -v $(pwd):/project zegl/kube-score:v1.7.0 score my-app/*.yaml

Configuration

Usage of kube-score:
kube-score [action] --flags

Actions:
score Checks all files in the input, and gives them a score and recommendations
list Prints a CSV list of all available score checks
version Print the version of kube-score
help Print this message

Flags for score:
--disable-ignore-checks-annotations Set to true to disable the effect of the 'kube-score/ignore' annotations
--enable-optional-test strings Enable an optional test, can be set multiple times
--exit-one-on-warning Exit with code 1 in case of warnings
--help Print help
--ignore-container-cpu-limit Disables the requirement of setting a container CPU limit
--ignore-container-memory-limit Disables the requirement of setting a container memory limi t
--ignore-test strings Disable a test, can be set multiple times
--kubernetes-version string Setting the kubernetes-version will affect the checks ran against the manifests. Set this to the version of Kubernetes that you're using in production for the best results. (default "v1.18")
-o, --output-format string Set to 'human', 'json' or 'ci'. If set to ci, kube-score will output the program in a format that is easier to parse by other programs. (default "human")
--output-version string Changes the version of the --output-format. The 'json' format has version 'v2' (default) and 'v1' (deprecated, will be removed in v1.7.0). The 'human' and 'ci' formats has only version 'v1' (default). If not explicitly set, the default version for that particular output format will be used.
-v, --verbose count Enable verbose output, can be set multiple times for increased verbosity.

Ignoring a test

Tests can be ignored in the whole run of the program, with the --ignore-test flag.

A test can also be ignored on a per-object basis, by adding the annotation kube-score/ignore to the object. The value should be a comma separated string of the test IDs.

Example:

Testing this object will temporarily disable the service-type test, which warns against using services of type NodePort.

apiVersion: v1
kind: Service
metadata:
name: node-port-service-with-ignore
namespace: foospace
annotations:
kube-score/ignore: service-type
spec:
selector:
app: my-app
ports:
- protocol: TCP
port: 80
targetPort: 8080
type: NodePort

Building from source

kube-score requires Go 1.11 or later to build. Clone this repository, and then:

# Build the project
go build github.com/zegl/kube-score/cmd/kube-score

# Run all tests
go test -v github.com/zegl/kube-score/...

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