helm-adopt

Overview

helm-adopt is a helm plugin to adopt existing k8s resources into a new generated helm chart, the idea behind the plugin was inspired by issue 2730.

adopt plugin allows you to :

adopt existing k8s resources by generating a helm chart
migrate adopted resources to be controlled by helm
create a helm release using secret as driver
perform a dry-run/debug-mode (optional)

Note: adopt does not re-create resources.

Getting started

Installation

To install the plugin:

$ helm plugin install https://github.com/HamzaZo/helm-adopt

Update to latest

$ helm plugin update adopt

Install a specific version

$ helm plugin install https://github.com/HamzaZo/helm-adopt --version 0.3.1

You can also verify it's been installed using

$ helm plugin list

Usage

$ helm adopt Adopt k8s resources into a new helm chart. It's expected to match plural resources kinds. Usage: adopt [command] Available Commands: help Help about any command resources adopt k8s resources into a new generated helm chart Flags: -h, --help help for adopt

Use "adopt [command] --help" for more information about a command.

Adopt k8s resources

$ helm adopt resources -h
Adopt k8s resources into a new generated helm chart
Examples:              $ helm adopt resources deployments:nginx services:my-svc -o/--output frontend
$ helm adopt resources deployments:nginx clusterrolebindings:binding-rbac -o/--output frontend -n/--namespace <ns>
$ helm adopt resources statefulsets:nginx services:my-svc -r/--release RELEASE-NAME -o/--output frontend -c/--kube-context <ctx>
$ helm adopt resources deployments:nginx services:my-svc -r/--release RELEASE-NAME -o/--output frontend -k/--kubeconfig <kcfg>
Usage:   adopt resources <pluralKind>:<name> [flags]
Flags:       --debug-mode            Show the generated manifests on STDOUT       --dry-run               Print what resources will be adopted    -h, --help                  help for resources   -c, --kube-context string   name of the kubeconfig context to use   -k, --kubeconfig string     path to the kubeconfig file   -n, --namespace string      namespace scope for this request   -o, --output string         Specify the chart directory of loaded yaml files   -r, --release string        Specify the name for the generated release

Example User case

In the following example the adopt plugin will :

Generate a chart directory called example
adopt frontend,backend deployments and generate deployments-0.yaml deployments-1.yaml files.
adopt frontend,backend services and generate services-0.yaml services-1.yaml files.
adopt default-lr limitranges and generate limitranges-0.yaml file.
migrate adopted resources control to Helm
create example release with version 1 using secret as driver.

$ helm adopt resources deployments:frontend,backend services:frontend,backend limitranges:default-lr --output example --release example
INFO[0000] Adopting resources..                         
INFO[0000] Generating chart example                     
INFO[0000] Added resource as file deployments-0 into example chart 
INFO[0000] Added resource as file deployments-1 into example chart 
INFO[0000] Added resource as file limitranges-0 into example chart 
INFO[0000] Added resource as file services-0 into example chart 
INFO[0000] Added resource as file services-1 into example chart 
INFO[0000] Chart example is released as example.1

Note: You must use a semicolon after each name <pluralKind>:<name>,<name>,<name> if you need to adopt a bunch of resources under a specific pluralKind as shown in the example above.

check the release status

$ helm ls NAME    NAMESPACE       REVISION        UPDATED                                 STATUS          CHART           APP VERSION example default         1               2021-05-18 12:04:53.171943 +0200 CEST   deployed        example-0.1.0   0.1.0

$ kubectl get secret
NAME                            TYPE                                  DATA   AGE
sh.helm.release.v1.example.v1   helm.sh/release.v1                    1      51s

check generated chart directory.

$ tree example example ├── Chart.yaml ├── charts ├── templates │ ├── _helpers.tpl │ ├── deployments-0.yaml │ ├── deployments-1.yaml │ ├── limitranges-0.yaml │ ├── services-0.yaml │ └── services-1.yaml └── values.yaml

2 directories, 8 files

Afterwards, you can edit the manifests in example/templates and turn them into templates and/or rework the generated chart into subcharts and then do a helm upgrade to fully transform the release.

Hints: To find out the pluralKind for a specific kind use kubectl api-resources

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