Windows Container Support¶
The Argo server and the workflow controller currently only run on Linux. The workflow executor however also runs on Windows nodes, meaning you can use Windows containers inside your workflows! Here are the steps to get started.
- Kubernetes 1.14 or later, supporting Windows nodes
- Hybrid cluster containing Linux and Windows nodes like described in the Kubernetes docs
- Argo configured and running like described here
Schedule workflows with Windows containers¶
If you're running workflows in your hybrid Kubernetes cluster, always make sure to include a
nodeSelector to run the steps on the correct host OS:
apiVersion: argoproj.io/v1alpha1 kind: Workflow metadata: generateName: hello-windows- spec: entrypoint: hello-win templates: - name: hello-win nodeSelector: kubernetes.io/os: windows # specify the OS your step should run on container: image: mcr.microsoft.com/windows/nanoserver:1809 command: ["cmd", "/c"] args: ["echo", "Hello from Windows Container!"]
You can run this example and get the logs:
$ argo submit --watch https://raw.githubusercontent.com/argoproj/argo-workflows/master/examples/hello-windows.yaml $ argo logs hello-windows-s9kk5 hello-windows-s9kk5: "Hello from Windows Container!"
Schedule hybrid workflows¶
You can also run different steps on different host operating systems. This can for example be very helpful when you need to compile your application on Windows and Linux.
An example workflow can look like the following:
apiVersion: argoproj.io/v1alpha1 kind: Workflow metadata: generateName: hello-hybrid- spec: entrypoint: mytemplate templates: - name: mytemplate steps: - - name: step1 template: hello-win - - name: step2 template: hello-linux - name: hello-win nodeSelector: kubernetes.io/os: windows container: image: mcr.microsoft.com/windows/nanoserver:1809 command: ["cmd", "/c"] args: ["echo", "Hello from Windows Container!"] - name: hello-linux nodeSelector: kubernetes.io/os: linux container: image: alpine command: [echo] args: ["Hello from Linux Container!"]
Again, you can run this example and get the logs:
$ argo submit --watch https://raw.githubusercontent.com/argoproj/argo-workflows/master/examples/hello-hybrid.yaml $ argo logs hello-hybrid-plqpp hello-hybrid-plqpp-1977432187: "Hello from Windows Container!" hello-hybrid-plqpp-764774907: Hello from Linux Container!
Artifact mount path¶
Artifacts work mostly the same way as on Linux. All paths get automatically mapped to the
C: drive. For example:
# ... - name: print-message inputs: artifacts: # unpack the message input artifact # and put it at C:\message - name: message path: "/message" # gets mapped to C:\message nodeSelector: kubernetes.io/os: windows container: image: mcr.microsoft.com/windows/nanoserver:1809 command: ["cmd", "/c"] args: ["dir C:\\message"] # List the C:\message directory
Remember that volume mounts on Windows can only target a directory in the container, and not an individual file.
- Sharing process namespaces doesn't work on Windows so you can't use the Process Namespace Sharing (PNS) workflow executor.
- The executor Windows container is built using Nano Server as the base image. Running a newer windows version (e.g. 1909) is currently not confirmed to be working. If this is required, you need to build the executor container yourself by first adjusting the base image.
Building the workflow executor image for Windows¶
To build the workflow executor image for Windows you need a Windows machine running Windows Server 2019 with Docker installed like described in the docs.
You then clone the project and run the Docker build with the
Dockerfile for Windows and
argoexec as a target:
git clone https://github.com/argoproj/argo-workflows.git cd argo docker build -t myargoexec -f .\Dockerfile.windows --target argoexec .