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Creating windows containers for .NET applications (4.x .NET Framework) and deploying to Kubernetes

Description

In this tutorial, we will learn how containerize .NET applications developed for 4.x versions of .NET framework using windows containers and deploy them to Kubernetes cluster using Move2Kube. Here, we are going to use the sample WCF service from samples/wcfservice.

Prerequisites

  1. Install Move2Kube

  2. Kubernetes with windows node support

  3. Download the samples/wcfservice sample from move2kube-demos repository

     $ curl https://move2kube.konveyor.io/scripts/download.sh | bash -s -- -d samples/wcfservice -r move2kube-demos

    $ tree -L 2 wcfservice/
 wcfservice/
 ├── wcfservice
 │   ├── App.config
 │   ├── IWindowsSampleService.cs
 │   ├── Properties
 │   ├── WindowsSampleService.cs
 │   ├── wcfservice.cs
 │   └── wcfservice.csproj
 └── wcfservice.sln

 2 directories, 6 files

Steps to generate target artifacts

We will be using the two stage process (plan and transform) for the transformation. Run these steps from the directory containing the ./wcfservice/ directory:

  1. First we create a plan on how to transform the applications to run on Kubernetes. In the plan phase, Move2Kube is going to go through the source artifacts and going to come up with a plan for us.

     $ move2kube plan -s wcfservice
 INFO[0000] Configuration loading done                   
 INFO[0000] Planning Transformation - Base Directory     
 INFO[0000] [CloudFoundry] Planning transformation       
 INFO[0000] [CloudFoundry] Done                          
 INFO[0000] [DockerfileDetector] Planning transformation 
 INFO[0000] [DockerfileDetector] Done                    
 INFO[0000] [ComposeAnalyser] Planning transformation    
 INFO[0000] [ComposeAnalyser] 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 . 
 WARN[0000] Unable to find compatible ASP.NET Core target framework  hence skipping. 
 INFO[0000] Transformation planning - Directory Walk done 
 INFO[0000] [Directory Walk] Identified 1 named services and 0 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 [/Users/padmanabha/go/src/github.com/seshapad/workdir/dotnet-legacy-test/m2k.plan].
    • It has created a m2k.plan which is essentially a yaml file. Let’s see what is inside the plan file. 
        apiVersion: move2kube.konveyor.io/v1alpha1
  kind: Plan
  metadata:
  name: myproject
  spec:
  sourceDir: wcfservice
  services:
      wcfservice:
      - transformerName: WinConsoleApp-Dockerfile
          paths:
          AppConfigFilePathList:
              - wcfservice/App.config
          ServiceDirPath:
              - .
  transformers:
      Buildconfig: m2kassets/built-in/transformers/kubernetes/buildconfig/transformer.yaml
      CloudFoundry: m2kassets/built-in/transformers/cloudfoundry/transformer.yaml
      ClusterSelector: m2kassets/built-in/transformers/kubernetes/clusterselector/transformer.yaml
      ComposeAnalyser: m2kassets/built-in/transformers/compose/composeanalyser/transformer.yaml
      ComposeGenerator: m2kassets/built-in/transformers/compose/composegenerator/transformer.yaml
      ContainerImagesPushScriptGenerator: m2kassets/built-in/transformers/containerimagespushscript/transformer.yaml
      DockerfileDetector: m2kassets/built-in/transformers/dockerfile/dockerfiledetector/transformer.yaml
      DockerfileImageBuildScript: m2kassets/built-in/transformers/dockerfile/dockerimagebuildscript/transformer.yaml
      DockerfileParser: m2kassets/built-in/transformers/dockerfile/dockerfileparser/transformer.yaml
      DotNetCore-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/dotnetcore/transformer.yaml
      EarAnalyser: m2kassets/built-in/transformers/dockerfilegenerator/java/earanalyser/transformer.yaml
      EarRouter: m2kassets/built-in/transformers/dockerfilegenerator/java/earrouter/transformer.yaml
      Golang-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/golang/transformer.yaml
      Gradle: m2kassets/built-in/transformers/dockerfilegenerator/java/gradle/transformer.yaml
      Jar: m2kassets/built-in/transformers/dockerfilegenerator/java/jar/transformer.yaml
      Jboss: m2kassets/built-in/transformers/dockerfilegenerator/java/jboss/transformer.yaml
      Knative: m2kassets/built-in/transformers/kubernetes/knative/transformer.yaml
      Kubernetes: m2kassets/built-in/transformers/kubernetes/kubernetes/transformer.yaml
      KubernetesVersionChanger: m2kassets/built-in/transformers/kubernetes/kubernetesversionchanger/transformer.yaml
      Liberty: m2kassets/built-in/transformers/dockerfilegenerator/java/liberty/transformer.yaml
      Maven: m2kassets/built-in/transformers/dockerfilegenerator/java/maven/transformer.yaml
      Nodejs-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/nodejs/transformer.yaml
      PHP-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/php/transformer.yaml
      Parameterizer: m2kassets/built-in/transformers/kubernetes/parameterizer/transformer.yaml
      Python-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/python/transformer.yaml
      ReadMeGenerator: m2kassets/built-in/transformers/readmegenerator/transformer.yaml
      Ruby-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/ruby/transformer.yaml
      Rust-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/rust/transformer.yaml
      Tekton: m2kassets/built-in/transformers/kubernetes/tekton/transformer.yaml
      Tomcat: m2kassets/built-in/transformers/dockerfilegenerator/java/tomcat/transformer.yaml
      WarAnalyser: m2kassets/built-in/transformers/dockerfilegenerator/java/waranalyser/transformer.yaml
      WarRouter: m2kassets/built-in/transformers/dockerfilegenerator/java/warrouter/transformer.yaml
      WinConsoleApp-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/windows/winconsole/transformer.yaml
      WinSLWebApp-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/windows/winsilverlightweb/transformer.yaml
      WinWebApp-Dockerfile: m2kassets/built-in/transformers/dockerfilegenerator/windows/winweb/transformer.yaml
      ZuulAnalyser: m2kassets/built-in/transformers/dockerfilegenerator/java/zuul/transformer.yaml
    • In the plan, you can see that Move2Kube has detected the WCF services (wcfservice) and relative path of the detected /App.config.
    • Also, the plan file is saying that the applications can be transformed using Move2Kube’s built-in WinConsoleApp-Dockerfile transformer.

  2. Let’s invoke move2kube transform on this plan.

     $ move2kube transform
 INFO[0000] Detected a plan file at path /Users/padmanabha/go/src/github.com/seshapad/workdir/dotnet-legacy-test/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.]
 [Use arrows to move, space to select, <right> to all, <left> to none, type to filter]
 [✓]  PHP-Dockerfile
 [✓]  Gradle
 [✓]  Kubernetes
 [✓]  Knative
 [✓]  Nodejs-Dockerfile
 [✓]  Tekton
 [✓]  ZuulAnalyser
 [✓]  ComposeAnalyser
 [✓]  Jar
 [✓]  Liberty
 [✓]  Python-Dockerfile
 [✓]  ContainerImagesPushScriptGenerator
 [✓]  Jboss
 [✓]  Parameterizer
 [✓]  WinSLWebApp-Dockerfile
 [✓]  Buildconfig
 [✓]  CloudFoundry
 [✓]  Ruby-Dockerfile
 [✓]  WinWebApp-Dockerfile
 [✓]  DockerfileDetector
 [✓]  Golang-Dockerfile
 [✓]  WinConsoleApp-Dockerfile
 [✓]  EarAnalyser
 [✓]  KubernetesVersionChanger
 [✓]  Maven
 [✓]  ClusterSelector
 [✓]  EarRouter
 [✓]  DockerfileParser
 [✓]  DotNetCore-Dockerfile
 [✓]  ReadMeGenerator
 [✓]  Rust-Dockerfile
 [✓]  Tomcat
 [✓]  WarAnalyser
 [✓]  ComposeGenerator
 [✓]  DockerfileImageBuildScript
 [✓]  WarRouter
    • Let’s go ahead with the default answer by pressing return or enter key.
     Hints:
 [Services that don't support any of the transformer types you are interested in will be ignored.]
 PHP-Dockerfile, Gradle, Kubernetes, Knative, Nodejs-Dockerfile, Tekton, ZuulAnalyser, ComposeAnalyser, Jar, Liberty, Python-Dockerfile, ContainerImagesPushScriptGenerator, Jboss, Parameterizer, WinSLWebApp-Dockerfile, Buildconfig, CloudFoundry, Ruby-Dockerfile, WinWebApp-Dockerfile, DockerfileDetector, Golang-Dockerfile, WinConsoleApp-Dockerfile, EarAnalyser, KubernetesVersionChanger, Maven, ClusterSelector, EarRouter, DockerfileParser, DotNetCore-Dockerfile, ReadMeGenerator, Rust-Dockerfile, Tomcat, WarAnalyser, ComposeGenerator, DockerfileImageBuildScript, WarRouter
 ? Select all services that are needed:
 ID: move2kube.services.[].enable
 Hints:
 [The services unselected here will be ignored.]
   [Use arrows to move, space to select, <right> to all, <left> to none, type to filter]
   [✓]  wcfservice
    • Here, we select all the services.
     ? Select all services that are needed:
 ID: move2kube.services.[].enable
 Hints:
 [The services unselected here will be ignored.]
 wcfservice
 INFO[0233] Starting Plan Transformation                 
 INFO[0233] Iteration 1                                  
 INFO[0233] Iteration 2 - 1 artifacts to process         
 INFO[0233] Transformer WinConsoleApp-Dockerfile processing 1 artifacts 
 INFO[0233] Transformer WinConsoleApp-Dockerfile Done    
 INFO[0233] Created 2 pathMappings and 2 artifacts. Total Path Mappings : 2. Total Artifacts : 1. 
 INFO[0233] Iteration 3 - 2 artifacts to process         
 INFO[0233] Transformer DockerfileParser processing 1 artifacts 
 WARN[0233] Unable to find ports in Dockerfile : /var/folders/45/5wf_qgcs06gd_xpg6rzvbx0r0000gn/T/move2kube2980808479/environment-DockerfileParser-1624209065/2318519572/source/Dockerfile. Using default port 
 INFO[0233] Transformer ZuulAnalyser processing 2 artifacts 
 INFO[0233] Transformer ZuulAnalyser Done                
 INFO[0233] Transformer DockerfileParser Done            
 INFO[0233] Transformer DockerfileImageBuildScript processing 2 artifacts 
 ? Select the container runtime to use :
 ID: move2kube.containerruntime
 Hints:
 [The container runtime selected will be used in the scripts]
   [Use arrows to move, type to filter]
 > docker
   podman

    • Here, we select runtime of choice. In this case, we select docker.

    • At this point, the default port 8080 is detected and the user is prompted on the modality of exposing this port.

     INFO[0346] Transformer DockerfileImageBuildScript Done  
 INFO[0346] Created 1 pathMappings and 4 artifacts. Total Path Mappings : 3. Total Artifacts : 3. 
 INFO[0346] Iteration 4 - 4 artifacts to process         
 INFO[0346] Transformer ComposeGenerator processing 2 artifacts 
 ? What URL/path should we expose the service wcfservice's 8080 port on?
 ID: move2kube.services."wcfservice"."8080".urlpath
 Hints:
 [Enter :- not expose the service, Leave out leading / to use first part as subdomain, Add :N as suffix for NodePort service type, Add :L for Load Balancer service type]
 (/wcfservice) wcfservice
    • We leave out the leading / to use the first part wcfservice as subdomain (as specified in the Hints).
     wcfservice
 ? Provide the minimum number of replicas each service should have
 ID: move2kube.minreplicas
 Hints:
 [If the value is 0 pods won't be started by default]
 (2)
    • Let’s go ahead with the default answer again, which means 2 replicas for the given service.
     2
 ? Enter the URL of the image registry : 
 Hints:
 [You can always change it later by changing the yamls.]
   [Use arrows to move, type to filter]
   Other (specify custom option)
   index.docker.io
 > quay.io
   us.icr.io
    • Then CLI asks to select the registry where your images are hosted. Here, we are selecting quay.io. Select ‘Other’ if your registry name is not here.
     quay.io
 ? Enter the namespace where the new images should be pushed :  
 Hints:
  [Ex : myproject]
  (myproject) m2k-tutorial

      No authentication
 INFO[0793] Transformer ComposeGenerator Done            
 INFO[0793] Transformer ClusterSelector processing 2 artifacts 
 ? Choose the cluster type:
 ID: move2kube.target.clustertype
 Hints:
 [Choose the cluster type you would like to target]
     [Use arrows to move, type to filter]
     Openshift
     AWS-EKS
     Azure-AKS
     GCP-GKE
     IBM-IKS
     IBM-Openshift
     > Kubernetes
    • Now, it asks to select the cluster type you want to deploy to. Here, we select the Kubernetes cluster type.
       Kubernetes
 INFO[0863] Transformer ClusterSelector Done             
 INFO[0863] Transformer Knative processing 2 artifacts   
 INFO[0863] Transformer Knative Done                     
 INFO[0863] Transformer ContainerImagesPushScriptGenerator processing 2 artifacts 
 INFO[0863] Transformer ContainerImagesPushScriptGenerator Done 
 INFO[0863] Transformer ClusterSelector processing 2 artifacts 
 INFO[0863] Transformer ClusterSelector Done             
 INFO[0863] Transformer Buildconfig processing 2 artifacts 
 INFO[0863] Transformer Buildconfig Done                 
 INFO[0863] Transformer ClusterSelector processing 2 artifacts 
 INFO[0863] Transformer ClusterSelector Done             
 INFO[0863] Transformer Kubernetes processing 2 artifacts 
 ? Provide the ingress host domain
 ID: move2kube.target.ingress.host
 Hints:
 [Ingress host domain is part of service URL]
     my-cluster-ingress-host-domain.com
    • CLI is now asking for the ingress hosting domain. It can be grabbed from the cluster you are going to deploy to. The ingress hosting domain will differ based on the cluster you are fetching from.
      my-cluster-ingress-host-domain.com
 ? Provide the TLS secret for ingress
 ID: move2kube.target.ingress.tls
 Hints:
 [Leave empty to use http]
    • Then it asks information about your TLS secret. Here we go with the by-default by pressing the ‘return’ key.
     INFO[0934] Transformer Kubernetes Done                  
 INFO[0934] Transformer ClusterSelector processing 2 artifacts 
 INFO[0934] Transformer ClusterSelector Done             
 INFO[0934] Transformer Tekton processing 2 artifacts    
 INFO[0934] Transformer Tekton Done                      
 INFO[0934] Created 27 pathMappings and 7 artifacts. Total Path Mappings : 30. Total Artifacts : 7. 
 INFO[0934] Iteration 5 - 7 artifacts to process         
 INFO[0934] Transformer Parameterizer processing 4 artifacts 
 INFO[0934] Transformer Parameterizer Done               
 INFO[0934] Transformer ReadMeGenerator processing 5 artifacts 
 INFO[0934] Transformer ReadMeGenerator Done             
 INFO[0935] Plan Transformation done                     
 INFO[0935] Transformed target artifacts can be found at [/Users/padmanabha/go/src/github.com/seshapad/workdir/dotnet-legacy-test/myproject].

Finally, the transformation is successful and the target artifacts can be found inside the ./myproject directory. The overview of the structure of the ./myproject directory can be seen by executing the below command.

$  tree -L 3 myproject
myproject/
├── Readme.md
├── deploy
│   ├── cicd
│   │   ├── tekton
│   │   └── tekton-parameterized
│   ├── compose
│   │   └── docker-compose.yaml
│   ├── knative
│   │   └── wcfservice-service.yaml
│   ├── knative-parameterized
│   │   ├── helm-chart
│   │   ├── kustomize
│   │   └── openshift-template
│   ├── yamls
│   │   ├── myproject-ingress.yaml
│   │   ├── wcfservice-deployment.yaml
│   │   └── wcfservice-service.yaml
│   └── yamls-parameterized
│       ├── helm-chart
│       ├── kustomize
│       └── openshift-template
├── scripts
│   ├── builddockerimages.bat
│   ├── builddockerimages.sh
│   ├── pushimages.bat
│   └── pushimages.sh
└── source
    ├── Dockerfile
    ├── wcfservice
    │   ├── App.config
    │   ├── IWindowsSampleService.cs
    │   ├── Properties
    │   ├── WindowsSampleService.cs
    │   ├── wcfservice.cs
    │   └── wcfservice.csproj
    └── wcfservice.sln

19 directories, 17 files

So, Move2Kube has created all the deployment artifacts which are present inside the ./myproject directory. The ./myproject/source directory looks very similar to the directory wcfservice that we gave as input to Move2Kube. But, Move2Kube has essentially instrumented the source code with additional files. For example, it has added the Dockerfile for each of the transformed services and with these dockerfiles the applications can be containerized and then deployed to a Kubernetes cluster.

What’s different in the case of windows application

  1. First difference is in the deployment yaml of windows container images (see myproject/deploy/yamls/wcfservice-deployment.yaml in the above example) . The nodeSelector and tolerations ensures that the image is instantiated on a windows node in the Kubernetes cluster. 
    nodeSelector:
kubernetes.io/os: windows
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
terminationGracePeriodSeconds: 30
tolerations:
- effect: NoSchedule
key: os
value: Windows
  2. Second difference is in the Dockerfile (see myproject/source/Dockerfile in the above example) for the windows service as shown below. The FROM instruction refers to windows container images and the --platform indicates that these images have to be built for a windows platform. 
     FROM --platform=windows/amd64 mcr.microsoft.com/dotnet/framework/sdk:4.8 As builder
 WORKDIR /app
 COPY . .
 RUN msbuild /p:Configuration=Release /p:OutputPath=/app/output

 FROM --platform=windows/amd64 mcr.microsoft.com/dotnet/framework/runtime:4.8
 WORKDIR /app
 COPY --from=builder /app/output/ .
 CMD wcfservice.exe

Deploying the application to Kubernetes with the generated target artifacts

The steps involved to deploy a windows application is the same as any other application except that the container images have to be built on a windows machine with Docker Desktop set to windows container mode. Please refer to .NET core deployment section for details.

Conclusion

In this tutorial, we learnt how to quickly migrate multiple .NET applications which are developed on 4.x .NET framework, to Kubernetes using the target artifacts generated by Move2Kube.