Chapter 3. Use fuse-overlayfs for containers

Procedure

1. Use the pod-overrides attribute to add the required annotations defined in Configuring fuse-overlayfs to the workspace. The pod-overrides attribute allows merging certain fields in the workspace pod’s spec.

   For OpenShift versions older than 4.15:

   $ oc patch devworkspace <DevWorkspace_name> \
     --patch '{"spec":{"template":{"attributes":{"pod-overrides":{"metadata":{"annotations":{"io.kubernetes.cri-o.Devices":"/dev/fuse","io.openshift.podman-fuse":""}}}}}}}' \
     --type=merge

   For OpenShift version 4.15 and later:

   $ oc patch devworkspace <DevWorkspace_name> \
     --patch '{"spec":{"template":{"attributes":{"pod-overrides":{"metadata":{"annotations":{"io.kubernetes.cri-o.Devices":"/dev/fuse"}}}}}}}' \
     --type=merge

Verification

1. Start the workspace and verify that /dev/fuse is available in the workspace container:

   $ stat /dev/fuse

Procedure

1. Create a ConfigMap that mounts a /home/user/.config/containers/storage.conf file:

   kind: ConfigMap
   apiVersion: v1
   metadata:
     name: fuse-overlay
     labels:
       controller.devfile.io/mount-to-devworkspace: 'true'
       controller.devfile.io/watch-configmap: 'true'
     annotations:
       controller.devfile.io/mount-as: subpath
       controller.devfile.io/mount-path: /home/user/.config/containers
   data:
     storage.conf: |
       [storage]
       driver = "overlay"
   
       [storage.options.overlay]
       mount_program = "/usr/bin/fuse-overlayfs"

2. Apply the ConfigMap to your project:

   Warning

   Applying this ConfigMap causes all running workspaces in the project to restart.

   $ oc apply -f fuse-overlay.yaml -n <your_namespace>

3. Start or restart your workspace.

Procedure

1. Add KUBEDOCK_ENABLED=true environment variable to the devfile.

2. Optional: Use the KUBEDOCK_PARAMS variable to specify additional kubedock parameters. The list of parameters is available in the kubedock server source. Alternatively, you can use the following command to view the available options:

   # kubedock server --help

3. Configure the Podman or docker API to point to kubedock by setting CONTAINER_HOST=tcp://127.0.0.1:2475 or DOCKER_HOST=tcp://127.0.0.1:2475 in the devfile.

   Important

   Configure Podman to point to local Podman when building containers, and to kubedock when running containers.

   The following example devfile enables kubedock with Testcontainers support:

   schemaVersion: 2.2.0
   metadata:
     name: kubedock-sample-devfile
   components:
     - name: tools
       container:
         image: quay.io/devfile/universal-developer-image:latest
         memoryLimit: 8Gi
         memoryRequest: 1Gi
         cpuLimit: "2"
         cpuRequest: 200m
         env:
           - name: KUBEDOCK_PARAMS
             value: "--reverse-proxy --kubeconfig /home/user/.kube/config --initimage quay.io/agiertli/kubedock:0.13.0"
           - name: USE_JAVA17
             value: "true"
           - value: /home/jboss/.m2
             name: MAVEN_CONFIG
           - value: -Xmx4G -Xss128M -XX:MetaspaceSize=1G -XX:MaxMetaspaceSize=2G
             name: MAVEN_OPTS
           - name: KUBEDOCK_ENABLED
             value: 'true'
           - name: DOCKER_HOST
             value: 'tcp://127.0.0.1:2475'
           - name: TESTCONTAINERS_RYUK_DISABLED
             value: 'true'
           - name: TESTCONTAINERS_CHECKS_DISABLE
             value: 'true'
         endpoints:
           - exposure: none
             name: kubedock
             protocol: tcp
             targetPort: 2475
           - exposure: public
             name: http-booster
             protocol: http
             targetPort: 8080
             attributes:
               discoverable: true
               urlRewriteSupported: true
           - exposure: internal
             name: debug
             protocol: http
             targetPort: 5005
         volumeMounts:
           - name: m2
             path: /home/user/.m2
     - name: m2
       volume:
         size: 10G

Procedure

1. Set the DOCKER_HOST environment variable to point to the Kubedock server:

   export DOCKER_HOST=tcp://127.0.0.1:2475

2. Start the Kubedock server in the background:

   kubedock server --port-forward &

3. Use standard Docker commands that Kubedock handles:

   docker run --rm hello-world