5c4b5b1bf0
This commit creates a new version of the alpha configuration functions framework. Goals include: - Make it easy to build multi-version APIs with the framework (not previously facilitated at all). - Simplify the framework's APIs where redundant configuration options exist (leaving the most powerful, replacing others with helpers to maintain usability they provided). - Make the Framework's APIs more consistent (e.g. between the various template types, usage of kio.Filter, field names) - Decouple responsibilities (e.g. command creation, resource list processing, generation of templating functions). - Make the framework even more powerfully pluggable (e.g. any kio.Filter can be a selector, and the selector the framework provides is itself a filter built from reusable abstractions). - Improve documentation. - Make container patches merge fields (notably list fields like `env`) correctly.
kustomize
kustomize lets you customize raw, template-free YAML
files for multiple purposes, leaving the original YAML
untouched and usable as is.
kustomize targets kubernetes; it understands and can
patch kubernetes style API objects. It's like
make, in that what it does is declared in a file,
and it's like sed, in that it emits edited text.
This tool is sponsored by sig-cli (KEP).
kubectl integration
The kustomize build flow at v2.0.3 was added to kubectl v1.14. The kustomize flow in kubectl has remained frozen at v2.0.3 while work to extract kubectl from the k/k repo, and work to remove kustomize's dependence on core k/k code (#2506) has proceeded. The reintegration effort is tracked in #1500 (and its blocking issues).
For examples and guides for using the kubectl integration please see the kubectl book or the kubernetes documentation.
Usage
1) Make a kustomization file
In some directory containing your YAML resource files (deployments, services, configmaps, etc.), create a kustomization file.
This file should declare those resources, and any customization to apply to them, e.g. add a common label.
File structure:
~/someApp ├── deployment.yaml ├── kustomization.yaml └── service.yaml
The resources in this directory could be a fork of someone else's configuration. If so, you can easily rebase from the source material to capture improvements, because you don't modify the resources directly.
Generate customized YAML with:
kustomize build ~/someApp
The YAML can be directly applied to a cluster:
kustomize build ~/someApp | kubectl apply -f -
2) Create variants using overlays
Manage traditional variants of a configuration - like development, staging and production - using overlays that modify a common base.
File structure:
~/someApp ├── base │ ├── deployment.yaml │ ├── kustomization.yaml │ └── service.yaml └── overlays ├── development │ ├── cpu_count.yaml │ ├── kustomization.yaml │ └── replica_count.yaml └── production ├── cpu_count.yaml ├── kustomization.yaml └── replica_count.yaml
Take the work from step (1) above, move it into a
someApp subdirectory called base, then
place overlays in a sibling directory.
An overlay is just another kustomization, referring to the base, and referring to patches to apply to that base.
This arrangement makes it easy to manage your
configuration with git. The base could have files
from an upstream repository managed by someone else.
The overlays could be in a repository you own.
Arranging the repo clones as siblings on disk avoids
the need for git submodules (though that works fine, if
you are a submodule fan).
Generate YAML with
kustomize build ~/someApp/overlays/production
The YAML can be directly applied to a cluster:
kustomize build ~/someApp/overlays/production | kubectl apply -f -
Community
- file a bug instructions
- contribute a feature instructions
Code of conduct
Participation in the Kubernetes community is governed by the Kubernetes Code of Conduct.