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https://github.com/kubecfg/k8s-libsonnet
Helpers for creating k8s resources without abuse of constructor functions
https://github.com/kubecfg/k8s-libsonnet
Last synced: 3 months ago
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Helpers for creating k8s resources without abuse of constructor functions
- Host: GitHub
- URL: https://github.com/kubecfg/k8s-libsonnet
- Owner: kubecfg
- License: mit
- Created: 2023-03-29T06:49:47.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2023-12-15T05:48:35.000Z (11 months ago)
- Last Synced: 2024-05-17T21:14:15.936Z (6 months ago)
- Language: Jsonnet
- Size: 26.4 KB
- Stars: 1
- Watchers: 0
- Forks: 0
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# k8s-libsonnet
Helpers for creating k8s resources without abuse of constructor functions.
## Features
* exposes k8s "named arrays" as objects that can be more easily overriden (`env_+:{BAR: {value:'override'}}`)
* allows to apply overrides on all objects of a given type, e.g. all Objects (e.g. namespace), all PodSpecs (e.g. labels)
## Example:
```jsonnet
(import '../k8s.libsonnet').RootComponent {
configmap: $.k8s.v1.ConfigMap {
metadata+: { name: 'foo' },
data: { bar: 'baz' },
},
deployment: $.k8s.apps.v1.Deployment {
metadata+: { name: 'nginx' },
spec+: {
replicas: 2,
selector+: { matchLabels: { app: 'nginx' } },
template+: {
metadata+: { labels: { app: 'nginx' } },
spec+: {
containers_+: {
nginx: {
image: 'nginx:1.14.2',
env_+: {
BAR: { valueFrom: { configMapKeyRef: {
name: $.configmap.metadata.name,
key: 'bar',
} } },
},
ports_+: {
http: { containerPort: 80 },
},
},
},
},
},
},
},
service: $.k8s.v1.Service {
metadata+: { name: 'nginx' },
spec+: {
selector+: $.deployment.spec.selector.matchLabels,
ports_+: {
http: { port: 80, targetPort: 'http' },
},
},
},
}
```
## Example: define namespace for all objects
```jsonnet
(import 'simple.jsonnet') {
k8s+: {
ObjectMeta+: {
namespace: 'my-ns',
},
},
}
```
## Example: add annotations to all resources including pods
Everything you add under `ObjectMeta` will be inherited by all objects you define in your templates.
A `Deployment` or a `StatefulSet` object will thus include the provided metadata in its own resource metadata.
When the `Deployment` or `StatefulSet` (or `Job`, `CronJob`, ...) create pods they do so using a `template` defined
in their spec. That template can contain a metadata object that will govern which metadata the "pod" resource will have.
If you want to add a metadata field that will appear in all resources, including those generated at runtime by resources such
as `Deployment` or `StatefulSet`, you can override the `ObjectTemplateMeta` field:
```jsonnet
(import 'simple.jsonnet') {
k8s+: {
ObjectTemplateMeta+: {
annotations+: {
'app.kubernetes.io/name': 'foo',
}
}
}
}
```
## Example: add annotations to a specific kind
```jsonnet
(import 'simple.jsonnet') {
k8s+: {
v1+: {
Service+: {
annotations+: {
'traefik.ingress.kubernetes.io/service.sticky.cookie.name': 'foobar',
}
}
}
}
}
```
## Example: overlay any pod template
There are many resource types that can create Pod (`Deployment`, `StatefulSet`, `Job`, ...).
All of them have a common way to express pod parameters, called a [`PodTemplateSpec`](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.28/#podtemplatespec-v1-core).
All the resource type templates defined in `k8s-libsonnet` that include a `PodTemplateSpec` share the same `k8s.PodTemplateSpec` template.
This means you can just extend that template and include overlays which will be shared by all pods.
A common use case are node selectors and tolerations:
```jsonnet
(import 'complex-app.jsonnet') {
k8s+: {
v1+: {
PodTemplateSpec+: {
metadata+: {
annotations+: {
'cluster-autoscaler.kubernetes.io/safe-to-evict': 'true'
}
},
spec+: {
nodeSelector+: {
'kubernetes.io/os': 'linux',
}
}
}
}
}
}
```
Note that with `PodTemplateSpec` you can add annotations that will only appear in pod template specs and not in the resource metadata on the root.
If you define metadata fields in the `ObjectTemplateMeta`, they will appear both here and in the root resource metadata.