neonvm: Move runner image env var into YAML (#988)

For neondatabase/cloud#10177, we want to be able to override the
neonvm-runner image that the controller uses *after* it's built and the
YAML is generated.

To do this, we need to actually define the runner image in the YAML
somewhere.

This commit:

1. Moves VM_RUNNER_IMAGE env var from the neonvm-controller dockerfile
   into its Pod spec.
2. Adds neonvm-runner-image-loader to neonvm.yaml (required for 1)

neonvm/Dockerfile

@@ -33,9 +33,6 @@ RUN CGO_ENABLED=0 GOOS=${TARGETOS:-linux} GOARCH=${TARGETARCH} go build -a -tags
 # Refer to https://github.com/GoogleContainerTools/distroless for more details
 FROM gcr.io/distroless/static:nonroot
 
-ARG VM_RUNNER_IMAGE=runner:dev
-ENV VM_RUNNER_IMAGE=${VM_RUNNER_IMAGE}
-
 WORKDIR /
 COPY --from=builder /workspace/manager .
 USER 65532:65532

neonvm/config/controller/deployment.yaml

@@ -64,6 +64,8 @@ spec:
         - "--failure-pending-period=1m"
         - "--failing-refresh-interval=15s"
         env:
+        - name: VM_RUNNER_IMAGE
+          value: $(VM_RUNNER_IMAGE) # will be replaced by kustomize based on neonvm-runner-image-loader image
         - name: NAD_IPAM_NAME
           value: $(NAD_IPAM_NAME)
         - name: NAD_IPAM_NAMESPACE

neonvm/config/kustomization.yaml

@@ -13,7 +13,6 @@ namePrefix: neonvm-
 #  someName: someValue
 
 bases:
-- namespace
 - crd
 - rbac
 - controller
@@ -24,12 +23,21 @@ bases:
 - vxlan-controller
 - network
 - device-plugin
+- ../runner-image-loader
 
 patchesStrategicMerge:
 - webhookcainjection_patch.yaml
 
 # the following config is for teaching kustomize how to do var substitution
 vars:
+- name: VM_RUNNER_IMAGE # full name of the neonvm-runner image
+  objref:
+    kind: DaemonSet
+    name: runner-image-loader
+    group: apps
+    version: v1
+  fieldref:
+    fieldpath: spec.template.spec.containers.[name=neonvm-runner-loader].image
 - name: CERTIFICATE_NAMESPACE # namespace of the certificate CR
   objref:
     kind: Certificate

neonvm/runner-image-loader/daemonset.yaml

@@ -16,6 +16,10 @@ spec:
         name: neonvm-runner-image-loader
     spec:
       containers:
+        # NOTE: this image is referenced by kustomize in order to set the value of the
+        # neonvm-controller's VM_RUNNER_IMAGE env var. We do it that way so that we can use
+        # 'kustomize edit image' to set the runner image, even if it does require some
+        # spooky action at a distance.
       - image: runner:dev
         name: neonvm-runner-loader
         command: ["sh", "-c", "echo 'image loaded and container started' && sleep 100d"]