edna

README

Edna

Edna is a Kubernetes manifest linter. This project was built as a personal learning exercise to understand how linters work and is not intended for production use.

Overview

• Installation
• Getting Started
• Configuration
• Example Output
• LICENSE

Installation

From GitHub Releases

Download the latest pre-built binary for your platform from the GitHub Releases page. Extract the archive, place the edna binary in your system PATH, and verify the installation:

edna version

Build from Source

Clone the repository and build the binary locally:

git clone https://github.com/patrikjokhel/edna.git
cd edna
make build

Place the resulting edna binary in your system PATH.

Using go install

Install the latest version directly via the Go toolchain:

go install github.com/patrikjokhel/edna@latest

Ensure your Go binary directory (default $(go env GOPATH)/bin) is added to your system PATH.

Getting Started

Edna provides a command-line interface to validate Kubernetes manifests and live cluster resources. The primary command is edna check, which supports three input modes:

Check Local Manifest Files

Validate individual YAML files or directories of manifests:

# Single file
edna check -f deployment.yaml

# Directory (recursive scan)
edna check -f ./manifests/

# Multiple files
edna check -f app.yaml -f service.yaml

Check from Standard Input

Pipe output from kubectl or other tools directly into Edna:

kubectl get deployments -o yaml | edna check
cat deployment.yaml | edna check

Check Live Cluster Resources

Query resources directly from your active Kubernetes cluster:

# Check default namespace
edna check --cluster

# Check specific namespace
edna check --cluster -n production

Output Formats

By default, Edna outputs human-readable results. To retrieve results in JSON format, use the --json flag:

edna check -f deployment.yaml --json

Version Information

Check the installed version of Edna:

edna version

Configuration

Edna supports configuration via .edna.yaml or .edna.yml placed in the working directory. The configuration file allows you to exclude files from scanning and customize rule behavior.

Excluding Files

Use the exclude key to specify file or directory patterns to skip during manifest scanning. Glob patterns are supported:

exclude:
  - "vendor/"
  - "*.generated.yaml"

Customizing Rules

The rules key is a map where each entry is keyed by the rule name (e.g., image-pull-policy). Each rule entry can have:

• enabled: Set to false to disable the rule (defaults to true if omitted)
• severity: Override the default severity with one of error, warning, or info

Example configuration:

exclude:
  - "vendor/"

rules:
  latest-tag:
    enabled: false

  image-pull-policy:
    enabled: true
    severity: error

For a full list of available rules and their names, see LINT_RULES.md.

Example Output

Running edna check against the sample manifests with lint violations produces output like the following:

edna check -f ./tests/testdata/

ERROR:
  tests/testdata/latest-tag.yaml: default/Deployment/test-latest-tag: Image has latest or no tag: nginx:latest
  tests/testdata/resource-balance.yaml: default/Deployment/test-resource-balance: Container 'nginx' has a lower memory limit (128Mi) set than requested (256Mi)!
  tests/testdata/resource-balance.yaml: default/Deployment/test-resource-balance: Container 'nginx' has a lower cpu limit (100m) set than requested (200m)!

WARNING:
  tests/testdata/image-pull-policy.yaml: default/Deployment/test-image-pull-policy: Image pull policy is not set to 'Always', but 'IfNotPresent'
  tests/testdata/unused-labels.yaml: default/Deployment/test-unused-labels: Label 'unused-label:test' is unused
  tests/testdata/unused-labels.yaml: default/Deployment/test-unused-labels: Label 'unused-label:test' is unused
  tests/testdata/resource-request.yaml: default/Deployment/test-resource-request: Container 'nginx' has no CPU request set!
  tests/testdata/resource-request.yaml: default/Deployment/test-resource-request: Container 'nginx' has no Memory request set!
  tests/testdata/resource-limit.yaml: default/Deployment/test-resource-limit: Container 'nginx' has no CPU limit set!
  tests/testdata/resource-limit.yaml: default/Deployment/test-resource-limit: Container 'nginx' has no Memory limit set!

Found 3 error(s), 7 warning(s), 0 info

LICENSE

Edna is licensed under the MIT license.