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The kubeconform package has been accepted to winget, see https://github.com/microsoft/winget-pkgs/pull/101691
354 lines
16 KiB
Markdown
354 lines
16 KiB
Markdown
<img width="50%" alt="Kubeconform-GitHub-Hero" src="https://user-images.githubusercontent.com/19731161/142411871-f695e40c-bfa8-43ca-97c0-94c256749732.png">
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<hr>
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[](https://github.com/yannh/kubeconform/actions?query=branch%3Amaster)
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[](https://formulae.brew.sh/formula/kubeconform)
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[](https://goreportcard.com/report/github.com/yannh/kubeconform)
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[](https://pkg.go.dev/github.com/yannh/kubeconform/pkg/validator)
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`Kubeconform` is a Kubernetes manifest validation tool. Incorporate it into your CI, or use it locally to validate your Kubernetes configuration!
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It is inspired by, contains code from and is designed to stay close to
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[Kubeval](https://github.com/instrumenta/kubeval), but with the following improvements:
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* **high performance**: will validate & download manifests over multiple routines, caching
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downloaded files in memory
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* configurable list of **remote, or local schemas locations**, enabling validating Kubernetes
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custom resources (CRDs) and offline validation capabilities
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* uses by default a [self-updating fork](https://github.com/yannh/kubernetes-json-schema) of the schemas registry maintained
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by the kubernetes-json-schema project - which guarantees
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up-to-date **schemas for all recent versions of Kubernetes**.
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<details><summary><h4>Speed comparison with Kubeval</h4></summary><p>
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Running on a pretty large kubeconfigs setup, on a laptop with 4 cores:
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```bash
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$ time kubeconform -ignore-missing-schemas -n 8 -summary preview staging production
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Summary: 50714 resources found in 35139 files - Valid: 27334, Invalid: 0, Errors: 0 Skipped: 23380
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real 0m6,710s
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user 0m38,701s
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sys 0m1,161s
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$ time kubeval -d preview,staging,production --ignore-missing-schemas --quiet
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[... Skipping output]
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real 0m35,336s
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user 0m0,717s
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sys 0m1,069s
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```
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</p></details>
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## Table of contents
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* [A small overview of Kubernetes manifest validation](#a-small-overview-of-kubernetes-manifest-validation)
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* [Limits of Kubeconform validation](#Limits-of-Kubeconform-validation)
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* [Installation](#Installation)
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* [Usage](#Usage)
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* [Usage examples](#Usage-examples)
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* [Proxy support](#Proxy-support)
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* [Overriding schemas location](#Overriding-schemas-location)
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* [CustomResourceDefinition (CRD) Support](#CustomResourceDefinition-(CRD)-Support)
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* [OpenShift schema Support](#OpenShift-schema-Support)
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* [Integrating Kubeconform in the CI](#Integrating-Kubeconform-in-the-CI)
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* [Github Workflow](#Github-Workflow)
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* [Gitlab-CI](#Gitlab-CI)
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* [Helm charts](#helm-charts)
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* [Using kubeconform as a Go Module](#Using-kubeconform-as-a-Go-Module)
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* [Credits](#Credits)
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## A small overview of Kubernetes manifest validation
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Kubernetes's API is described using the [OpenAPI (formerly swagger) specification](https://www.openapis.org),
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in a [file](https://github.com/kubernetes/kubernetes/blob/master/api/openapi-spec/swagger.json) checked into
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the main Kubernetes repository.
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Because of the state of the tooling to perform validation against OpenAPI schemas, projects usually convert
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the OpenAPI schemas to [JSON schemas](https://json-schema.org/) first. Kubeval relies on
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[instrumenta/OpenApi2JsonSchema](https://github.com/instrumenta/openapi2jsonschema) to convert Kubernetes' Swagger file
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and break it down into multiple JSON schemas, stored in github at
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[instrumenta/kubernetes-json-schema](https://github.com/instrumenta/kubernetes-json-schema) and published on
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[kubernetesjsonschema.dev](https://kubernetesjsonschema.dev/).
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`Kubeconform` relies on [a fork of kubernetes-json-schema](https://github.com/yannh/kubernetes-json-schema/)
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that is more meticulously kept up-to-date, and contains schemas for all recent versions of Kubernetes.
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### Limits of Kubeconform validation
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`Kubeconform`, similar to `kubeval`, only validates manifests using the official Kubernetes OpenAPI specifications. The Kubernetes controllers still perform additional server-side validations that are not part of the OpenAPI specifications. Those server-side validations are not covered by `Kubeconform` (examples: [#65](https://github.com/yannh/kubeconform/issues/65), [#122](https://github.com/yannh/kubeconform/issues/122), [#142](https://github.com/yannh/kubeconform/issues/142)). You can use a 3rd-party tool or the `kubectl --dry-run=server` command to fill the missing (validation) gap.
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## Installation
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If you are a [Homebrew](https://brew.sh/) user, you can install by running:
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```bash
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$ brew install kubeconform
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```
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If you are a Windows user, you can install with [winget](https://learn.microsoft.com/en-us/windows/package-manager/winget/) by running:
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```cmd
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winget install YannHamon.kubeconform
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```
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You can also download the latest version from the [release page](https://github.com/yannh/kubeconform/releases).
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Another way of installation is via Golang's package manager:
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```bash
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# With a specific version tag
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$ go install github.com/yannh/kubeconform/cmd/kubeconform@v0.4.13
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# Latest version
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$ go install github.com/yannh/kubeconform/cmd/kubeconform@latest
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```
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## Usage
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```
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$ kubeconform -h
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Usage: ./bin/kubeconform [OPTION]... [FILE OR FOLDER]...
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-cache string
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cache schemas downloaded via HTTP to this folder
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-debug
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print debug information
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-exit-on-error
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immediately stop execution when the first error is encountered
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-h show help information
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-ignore-filename-pattern value
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regular expression specifying paths to ignore (can be specified multiple times)
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-ignore-missing-schemas
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skip files with missing schemas instead of failing
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-insecure-skip-tls-verify
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disable verification of the server\'s SSL certificate. This will make your HTTPS connections insecure
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-kubernetes-version string
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version of Kubernetes to validate against, e.g.: 1.18.0 (default "master")
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-n int
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number of goroutines to run concurrently (default 4)
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-output string
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output format - json, junit, tap, text (default "text")
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-reject string
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comma-separated list of kinds or GVKs to reject
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-schema-location value
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override schemas location search path (can be specified multiple times)
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-skip string
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comma-separated list of kinds or GVKs to ignore
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-strict
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disallow additional properties not in schema or duplicated keys
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-summary
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print a summary at the end (ignored for junit output)
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-v show version information
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-verbose
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print results for all resources (ignored for tap and junit output)
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```
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### Usage examples
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* Validating a single, valid file
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```bash
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$ kubeconform fixtures/valid.yaml
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$ echo $?
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0
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```
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* Validating a single invalid file, setting output to json, and printing a summary
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```bash
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$ kubeconform -summary -output json fixtures/invalid.yaml
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{
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"resources": [
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{
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"filename": "fixtures/invalid.yaml",
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"kind": "ReplicationController",
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"version": "v1",
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"status": "INVALID",
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"msg": "Additional property templates is not allowed - Invalid type. Expected: [integer,null], given: string"
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}
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],
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"summary": {
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"valid": 0,
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"invalid": 1,
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"errors": 0,
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"skipped": 0
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}
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}
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$ echo $?
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1
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```
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* Passing manifests via Stdin
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```bash
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cat fixtures/valid.yaml | ./bin/kubeconform -summary
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Summary: 1 resource found parsing stdin - Valid: 1, Invalid: 0, Errors: 0 Skipped: 0
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```
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* Validating a file, ignoring its resource using both Kind, and GVK (Group, Version, Kind) notations
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```
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# This will ignore ReplicationController for all apiVersions
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$ kubeconform -summary -skip ReplicationController fixtures/valid.yaml
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Summary: 1 resource found in 1 file - Valid: 0, Invalid: 0, Errors: 0, Skipped: 1
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# This will ignore ReplicationController only for apiVersion v1
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$ kubeconform -summary -skip v1/ReplicationController fixtures/valid.yaml
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Summary: 1 resource found in 1 file - Valid: 0, Invalid: 0, Errors: 0, Skipped: 1
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```
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* Validating a folder, increasing the number of parallel workers
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```
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$ kubeconform -summary -n 16 fixtures
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fixtures/crd_schema.yaml - CustomResourceDefinition trainingjobs.sagemaker.aws.amazon.com failed validation: could not find schema for CustomResourceDefinition
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fixtures/invalid.yaml - ReplicationController bob is invalid: Invalid type. Expected: [integer,null], given: string
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[...]
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Summary: 65 resources found in 34 files - Valid: 55, Invalid: 2, Errors: 8 Skipped: 0
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```
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### Proxy support
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`Kubeconform` will respect the **HTTPS_PROXY** variable when downloading schema files.
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```bash
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$ HTTPS_PROXY=proxy.local bin/kubeconform fixtures/valid.yaml
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```
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## Overriding schemas location
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When the `-schema-location` parameter is not used, or set to `default`, kubeconform will default to downloading
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schemas from https://github.com/yannh/kubernetes-json-schema. Kubeconform however supports passing one, or multiple,
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schemas locations - HTTP(s) URLs, or local filesystem paths, in which case it will lookup for schema definitions
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in each of them, in order, stopping as soon as a matching file is found.
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* If the `-schema-location` value does not end with `.json`, Kubeconform will assume filenames / a file
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structure identical to that of [kubernetesjsonschema.dev](https://kubernetesjsonschema.dev/) or [yannh/kubernetes-json-schema](https://github.com/yannh/kubernetes-json-schema).
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* if the `-schema-location` value ends with `.json` - Kubeconform assumes the value is a **Go templated
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string** that indicates how to search for JSON schemas.
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* the `-schema-location` value of `default` is an alias for `https://raw.githubusercontent.com/yannh/kubernetes-json-schema/master/{{.NormalizedKubernetesVersion}}-standalone{{.StrictSuffix}}/{{.ResourceKind}}{{.KindSuffix}}.json`.
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**The following command lines are equivalent:**
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```bash
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$ kubeconform fixtures/valid.yaml
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$ kubeconform -schema-location default fixtures/valid.yaml
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$ kubeconform -schema-location 'https://raw.githubusercontent.com/yannh/kubernetes-json-schema/master/{{.NormalizedKubernetesVersion}}-standalone{{.StrictSuffix}}/{{.ResourceKind}}{{.KindSuffix}}.json' fixtures/valid.yaml
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```
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Here are the variables you can use in -schema-location:
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* *NormalizedKubernetesVersion* - Kubernetes Version, prefixed by v
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* *StrictSuffix* - "-strict" or "" depending on whether validation is running in strict mode or not
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* *ResourceKind* - Kind of the Kubernetes Resource
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* *ResourceAPIVersion* - Version of API used for the resource - "v1" in "apiVersion: monitoring.coreos.com/v1"
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* *Group* - the group name as stated in this resource's definition - "monitoring.coreos.com" in "apiVersion: monitoring.coreos.com/v1"
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* *KindSuffix* - suffix computed from apiVersion - for compatibility with `Kubeval` schema registries
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### CustomResourceDefinition (CRD) Support
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Because Custom Resources (CR) are not native Kubernetes objects, they are not included in the default schema.
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If your CRs are present in [Datree's CRDs-catalog](https://github.com/datreeio/CRDs-catalog), you can specify this project as an additional registry to lookup:
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```bash
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# Look in the CRDs-catalog for the desired schema/s
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$ kubeconform -schema-location default -schema-location 'https://raw.githubusercontent.com/datreeio/CRDs-catalog/main/{{.Group}}/{{.ResourceKind}}_{{.ResourceAPIVersion}}.json' [MANIFEST]
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```
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If your CRs are not present in the CRDs-catalog, you will need to manually pull the CRDs manifests from your cluster and convert the `OpenAPI.spec` to JSON schema format.
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<details><summary>Converting an OpenAPI file to a JSON Schema</summary>
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<p>
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`Kubeconform` uses JSON schemas to validate Kubernetes resources. For Custom Resource, the CustomResourceDefinition
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first needs to be converted to JSON Schema. A script is provided to convert these CustomResourceDefinitions
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to JSON schema. Here is an example how to use it:
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```bash
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$ python ./scripts/openapi2jsonschema.py https://raw.githubusercontent.com/aws/amazon-sagemaker-operator-for-k8s/master/config/crd/bases/sagemaker.aws.amazon.com_trainingjobs.yaml
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JSON schema written to trainingjob_v1.json
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```
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By default, the file name output format is `{kind}_{version}`. The `FILENAME_FORMAT` environment variable can be used to change the output file name (Available variables: `kind`, `group`, `version`):
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```
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$ export FILENAME_FORMAT='{kind}-{group}-{version}'
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$ ./scripts/openapi2jsonschema.py https://raw.githubusercontent.com/aws/amazon-sagemaker-operator-for-k8s/master/config/crd/bases/sagemaker.aws.amazon.com_trainingjobs.yaml
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JSON schema written to trainingjob-sagemaker-v1.json
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```
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After converting your CRDs to JSON schema files, you can use `kubeconform` to validate your CRs against them:
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```
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# If the resource Kind is not found in default, also lookup in the schemas/ folder for a matching file
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$ kubeconform -schema-location default -schema-location 'schemas/{{ .ResourceKind }}{{ .KindSuffix }}.json' fixtures/custom-resource.yaml
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```
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ℹ️ Datree's [CRD Extractor](https://github.com/datreeio/CRDs-catalog#crd-extractor) is a utility that can be used instead of this manual process.
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</p>
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</details>
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### OpenShift schema Support
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You can validate Openshift manifests using a custom schema location. Set the OpenShift version (v3.10.0-4.1.0) to validate
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against using `-kubernetes-version`.
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```
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kubeconform -kubernetes-version 3.8.0 -schema-location 'https://raw.githubusercontent.com/garethr/openshift-json-schema/master/{{ .NormalizedKubernetesVersion }}-standalone{{ .StrictSuffix }}/{{ .ResourceKind }}.json' -summary fixtures/valid.yaml
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Summary: 1 resource found in 1 file - Valid: 1, Invalid: 0, Errors: 0 Skipped: 0
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```
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## Integrating Kubeconform in the CI
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`Kubeconform` publishes Docker Images to Github's new Container Registry (ghcr.io). These images
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can be used directly in a Github Action, once logged in using a [_Github Token_](https://github.blog/changelog/2021-03-24-packages-container-registry-now-supports-github_token/).
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### Github Workflow
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Example:
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```yaml
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name: kubeconform
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on: push
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jobs:
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kubeconform:
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runs-on: ubuntu-latest
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steps:
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- name: login to Github Packages
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run: echo "${{ github.token }}" | docker login https://ghcr.io -u ${GITHUB_ACTOR} --password-stdin
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- uses: actions/checkout@v2
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- uses: docker://ghcr.io/yannh/kubeconform:master
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with:
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entrypoint: '/kubeconform'
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args: "-summary -output json kubeconfigs/"
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```
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_Note on pricing_: Kubeconform relies on Github Container Registry which is currently in Beta. During that period,
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[bandwidth is free](https://docs.github.com/en/packages/guides/about-github-container-registry). After that period,
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bandwidth costs might be applicable. Since bandwidth from Github Packages within Github Actions is free, I expect
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Github Container Registry to also be usable for free within Github Actions in the future. If that were not to be the
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case, I might publish the Docker image to a different platform.
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### Gitlab-CI
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The Kubeconform Docker image can be used in Gitlab-CI. Here is an example of a Gitlab-CI job:
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```yaml
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lint-kubeconform:
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stage: validate
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image:
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name: ghcr.io/yannh/kubeconform:latest-alpine
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entrypoint: [""]
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script:
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- kubeconform
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```
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See [issue 106](https://github.com/yannh/kubeconform/issues/106) for more details.
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## Helm charts
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There is a 3rd party [repository](https://github.com/jtyr/kubeconform-helm) that
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allows to use `kubeconform` to test [Helm charts](https://helm.sh) in the form of
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a [Helm plugin](https://helm.sh/docs/topics/plugins/) and [`pre-commit`
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hook](https://pre-commit.com/).
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## Using kubeconform as a Go Module
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**Warning**: This is a work-in-progress, the interface is not yet considered stable. Feedback is encouraged.
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`Kubeconform` contains a package that can be used as a library.
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An example of usage can be found in [examples/main.go](examples/main.go)
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Additional documentation on [pkg.go.dev](https://pkg.go.dev/github.com/yannh/kubeconform/pkg/validator)
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## Credits
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* @garethr for the [Kubeval](https://github.com/instrumenta/kubeval) and
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[kubernetes-json-schema](https://github.com/instrumenta/kubernetes-json-schema) projects ❤️
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