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Creating Helm-charts, Kustomize overlays from Kubernetes Yamls

Description

In this tutorial we will see how we can transform a set of Kubernetes YAMLs by parameterizing them. We can use Move2Kube to generate parameterized Helm charts, Kustomize and Openshift Templates from the Kubernetes YAMLs. Move2Kube can also change the versions of Kubernetes resources to target particular clusters.

Prerequisites

  1. Install the Move2Kube CLI tool

  2. We will use kubernetes-to-kubernetes sample. The kubernetes-to-kubernetes directory has some Kubernetes YAMLs that deploy a web app with multiple services. There are 3 services: a frontend website in PHP, a backend API in NodeJS and a cache service using Redis.

Steps

  1. Download the kubernetes-to-kubernetes sample.
  $ curl https://move2kube.konveyor.io/scripts/download.sh | bash -s -- -d samples/kubernetes-to-kubernetes -r move2kube-demos
  $ ls kubernetes-to-kubernetes/
  api-deployment.yaml  api-service.yaml  redis-deployment.yaml  redis-service.yaml  web-deployment.yaml  web-ingress.yaml  web-service.yaml
  1. Run move2kube plan -s kubernetes-to-kubernetes/ to generate a plan file. 
     # click to see the output
 $ move2kube plan -s kubernetes-to-kubernetes/

     $ move2kube plan -s kubernetes-to-kubernetes
 INFO[0000] Configuration loading done
 INFO[0000] Planning Transformation - Base Directory
 INFO[0000] [ComposeAnalyser] Planning transformation
 INFO[0000] [ComposeAnalyser] Done
 INFO[0000] [CloudFoundry] Planning transformation
 INFO[0000] [CloudFoundry] Done
 INFO[0000] [DockerfileDetector] Planning transformation
 INFO[0000] [DockerfileDetector] Done
 INFO[0000] [Base Directory] Identified 0 named services and 0 to-be-named services
 INFO[0000] Transformation planning - Base Directory done
 INFO[0000] Planning Transformation - Directory Walk
 INFO[0000] Identified 1 named services and 0 to-be-named services in .
 INFO[0000] Identified 1 named services and 0 to-be-named services in .
 INFO[0000] Transformation planning - Directory Walk done
 INFO[0000] [Directory Walk] Identified 1 named services and 1 to-be-named services
 INFO[0000] [Named Services] Identified 1 named services
 INFO[0000] No of services identified : 1
 INFO[0000] Plan can be found at [/home/user/m2k.plan].

  2. Now let’s look at the plan file we generated. The plan is in YAML format. We see that Move2Kube has detected all the different services, one for each web app.

     $ ls
 kubernetes-to-kubernetes	m2k.plan
 $ cat m2k.plan 

     # click to see the full plan yaml
 apiVersion: move2kube.konveyor.io/v1alpha1
 kind: Plan
 ......

     apiVersion: move2kube.konveyor.io/v1alpha1
 kind: Plan
 metadata:
   name: myproject
 spec:
   sourceDir: kubernetes-to-kubernetes
   services:
     myproject:
       - transformerName: KubernetesVersionChanger
         type: KubernetesOrgYamlsInSource
         paths:
           KubernetesYamls:
             - .
           ServiceDirPath:
             - .
       - transformerName: Parameterizer
         paths:
           KubernetesYamls:
             - .
           ServiceDirPath:
             - .
   transformers:
     Buildconfig: m2kassets/built-in/transformers/kubernetes/buildconfig/buildconfig.yaml
     CloudFoundry: m2kassets/built-in/transformers/cloudfoundry/cloudfoundry.yaml
     ClusterSelector: m2kassets/built-in/transformers/kubernetes/clusterselector/clusterselector.yaml
     ComposeAnalyser: m2kassets/built-in/transformers/compose/composeanalyser/composeanalyser.yaml
     ComposeGenerator: m2kassets/built-in/transformers/compose/composegenerator/composegenerator.yaml
     ContainerImagesPushScriptGenerator: m2kassets/built-in/transformers/containerimage/containerimagespushscript/containerimagespushscript.yaml
     DockerfileDetector: m2kassets/built-in/transformers/dockerfile/dockerfiledetector/dockerfiledetector.yaml
     DockerfileImageBuildScript: m2kassets/built-in/transformers/dockerfile/dockerimagebuildscript/dockerfilebuildscriptgenerator.yaml
     DockerfileParser: m2kassets/built-in/transformers/dockerfile/dockerfileparser/dockerfileparser.yaml
     DotNetCore-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/dotnetcore/dotnetcore.yaml
     EarAnalyser: m2kassets/built-in/transformers/dockerfilegenerator/java/earanalyser/ear.yaml
     EarRouter: m2kassets/built-in/transformers/dockerfilegenerator/java/earrouter/earrouter.yaml
     Golang-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/golang/golang.yaml
     Gradle: m2kassets/built-in/transformers/dockerfilegenerator/java/gradle/gradle.yaml
     Jar: m2kassets/built-in/transformers/dockerfilegenerator/java/jar/jar.yaml
     Jboss: m2kassets/built-in/transformers/dockerfilegenerator/java/jboss/jboss.yaml
     Knative: m2kassets/built-in/transformers/kubernetes/knative/knative.yaml
     Kubernetes: m2kassets/built-in/transformers/kubernetes/kubernetes/kubernetes.yaml
     KubernetesVersionChanger: m2kassets/built-in/transformers/kubernetes/kubernetesversionchanger/kubernetesversionchanger.yaml
     Liberty: m2kassets/built-in/transformers/dockerfilegenerator/java/liberty/liberty.yaml
     Maven: m2kassets/built-in/transformers/dockerfilegenerator/java/maven/maven.yaml
     Nodejs-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/nodejs/nodejs.yaml
     PHP-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/php/php.yaml
     Parameterizer: m2kassets/built-in/transformers/kubernetes/parameterizer/parameterizer.yaml
     Python-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/python/python.yaml
     ReadMeGenerator: m2kassets/built-in/transformers/readmegenerator/readmegenerator.yaml
     Ruby-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/ruby/ruby.yaml
     Rust-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/rust/rust.yaml
     Tekton: m2kassets/built-in/transformers/kubernetes/tekton/tekton.yaml
     Tomcat: m2kassets/built-in/transformers/dockerfilegenerator/java/tomcat/tomcat.yaml
     WarAnalyser: m2kassets/built-in/transformers/dockerfilegenerator/java/waranalyser/war.yaml
     WarRouter: m2kassets/built-in/transformers/dockerfilegenerator/java/warrouter/warrouter.yaml
     WinConsoleApp-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/windows/winconsole/winconsole.yaml
     WinSLWebApp-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/windows/winsilverlightweb/winsilverlightweb.yaml
     WinWebApp-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/windows/winweb/winweb.yaml
     ZuulAnalyser: m2kassets/built-in/transformers/dockerfilegenerator/java/zuul/zuulanalyser.yaml
  3. Now let’s run the transformation using move2kube transform. 
     # click to see the output
 $ move2kube transform

     $ move2kube transform
 INFO[0000] Detected a plan file at path /home/user/m2k.plan. Will transform using this plan.
 ? Select all transformer types that you are interested in:
 ID: move2kube.transformers.types
 Hints:
 [Services that don't support any of the transformer types you are interested in will be ignored.]
  ComposeAnalyser, PHP-Dockerfile, ReadMeGenerator, Ruby-Dockerfile, Tekton, Buildconfig, Golang-Dockerfile, Jar, Knative, Nodejs-Dockerfile, Parameterizer, CloudFoundry,     DockerfileDetector, Kubernetes, Maven, WinWebApp-Dockerfile, Gradle, KubernetesVersionChanger, WarAnalyser, Rust-Dockerfile, WarRouter, ZuulAnalyser, DotNetCore-Dockerfile,    EarRouter, Liberty, Python-Dockerfile, Tomcat, ContainerImagesPushScriptGenerator, DockerfileImageBuildScript, DockerfileParser, ClusterSelector, ComposeGenerator,   EarAnalyser, Jboss, WinConsoleApp-Dockerfile, WinSLWebApp-Dockerfile
 ? Select all services that are needed:
 ID: move2kube.services.[].enable
 Hints:
 [The services unselected here will be ignored.]
  myproject
 INFO[0005] Starting Plan Transformation
 INFO[0005] Iteration 1
 INFO[0005] Iteration 2 - 1 artifacts to process
 INFO[0005] Transformer ClusterSelector processing 1 artifacts
 ? Choose the cluster type:
 ID: move2kube.target.clustertype
 Hints:
 [Choose the cluster type you would like to target]
  Kubernetes
 INFO[0006] Transformer ClusterSelector Done
 INFO[0006] Transformer KubernetesVersionChanger processing 1 artifacts
 INFO[0006] Transformer KubernetesVersionChanger Done
 INFO[0006] Created 1 pathMappings and 1 artifacts. Total Path Mappings : 1. Total Artifacts : 1.
 INFO[0006] Iteration 3 - 1 artifacts to process
 INFO[0006] Transformer Parameterizer processing 1 artifacts
 INFO[0006] Transformer Parameterizer Done
 INFO[0006] Plan Transformation done
 INFO[0006] Transformed target artifacts can be found at [/home/user/myproject].
  4. After the questions are finished wait a few minutes for it to finish processing. Once it’s done, we can see it has generated a directory called myproject. The name of the output directory is the same as the project name (by default myproject). The project name be changed using the -n flag.
  $ ls
  kubernetes-to-kubernetes  m2k.plan  m2kconfig.yaml  m2kqacache.yaml  myproject

  $ ls myproject/
  source

The applications can now be deployed to Kubernetes using these generated artifacts.

Exploring the output

The full structure of the output directory can be seen by executing the tree command.

  $ cd myproject/
  $ tree
  .
  └── source
      ├── kubernetes-to-kubernetes-versionchanged
      │   ├── api-deployment.yaml
      │   ├── api-service.yaml
      │   ├── redis-deployment.yaml
      │   ├── redis-service.yaml
      │   ├── web-deployment.yaml
      │   ├── web-ingress.yaml
      │   └── web-service.yaml
      └── kubernetes-to-kubernetes-versionchanged-parameterized
          ├── helm-chart
          │   └── myproject
          │       ├── Chart.yaml
          │       ├── templates
          │       │   ├── api-deployment.yaml
          │       │   ├── api-service.yaml
          │       │   ├── redis-deployment.yaml
          │       │   ├── redis-service.yaml
          │       │   ├── web-deployment.yaml
          │       │   ├── web-ingress.yaml
          │       │   └── web-service.yaml
          │       ├── values-dev.yaml
          │       ├── values-prod.yaml
          │       └── values-staging.yaml
          ├── kustomize
          │   ├── base
          │   │   ├── api-deployment.yaml
          │   │   ├── api-service.yaml
          │   │   ├── kustomization.yaml
          │   │   ├── redis-deployment.yaml
          │   │   ├── redis-service.yaml
          │   │   ├── web-deployment.yaml
          │   │   ├── web-ingress.yaml
          │   │   └── web-service.yaml
          │   └── overlays
          │       ├── dev
          │       │   ├── apps-v1-deployment-api.yaml
          │       │   ├── apps-v1-deployment-redis.yaml
          │       │   ├── apps-v1-deployment-web.yaml
          │       │   └── kustomization.yaml
          │       ├── prod
          │       │   ├── apps-v1-deployment-api.yaml
          │       │   ├── apps-v1-deployment-redis.yaml
          │       │   ├── apps-v1-deployment-web.yaml
          │       │   └── kustomization.yaml
          │       └── staging
          │           ├── apps-v1-deployment-api.yaml
          │           ├── apps-v1-deployment-redis.yaml
          │           ├── apps-v1-deployment-web.yaml
          │           └── kustomization.yaml
          └── openshift-template
              ├── parameters-dev.yaml
              ├── parameters-prod.yaml
              ├── parameters-staging.yaml
              └── template.yaml
  13 directories, 42 files

Some things we can observe:

  • We can see the Helm chart in the source/kubernetes-to-kubernetes-versionchanged-parameterized/helm-chart directory.
  • We can see the Kustomize YAMLs in the source/kubernetes-to-kubernetes-versionchanged-parameterized/kustomize directory.
  • We can see the Openshift Template in the source/kubernetes-to-kubernetes-versionchanged-parameterized/openshift-template directory.
  • We can also see that, in each case, there are 3 environments dev, staging and prod.
  • It is possible to have different parameterizations for each environment.

You might have noticied that the directory name has versionchanged in it. This is because two transformers are currently in play here,

  • The KubernetesVersionChanger transformer, which was asking for the Kubernetes version to target, and which created the version changed yamls to suit the target cluster supported Kinds and versions.
  • The Parameterizer transformer, which was taking the version changed yamls and creating Helm charts, Kustomize overlays and OC templates.

If the intention was to retain the kind and verisons of Kubernetes yamls, we can disable the KubernetesVersionChanger transformer either in the QA, config or in plan, and then the yamls will be parameterized as is.

For more details on how to customize the parameterization that Move2Kube does look at the documentation.

Conclusion

Given Kubernetes YAMLs, we saw how Move2Kube can help us parameterize them and generate Helm charts, Kustomize, Openshift Templates, etc. Move2Kube is also capable of changing the versions of various Kubernetes resources to match the target cluster.