Push Docker images as part of the release workflow

.github/workflows/release.yml

@@ -109,6 +109,52 @@ jobs:
           name: darwin-latest
           path: ./release/*
 
+  build-docker:
+    name: Create and Upload Docker Images
+    # Technically we only need build-linux to succeed, but if any platforms fail we'll
+    # want to investigate and restart the build
+    needs: [build-linux, build-darwin, build-windows]
+    runs-on: ubuntu-latest
+    env:
+      HAS_DOCKER_CREDS: ${{ vars.DOCKERHUB_USERNAME != '' && secrets.DOCKERHUB_TOKEN != '' }}
+    # XXX It's not possible to write a conditional here, so instead we do it on every step
+    #if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
+    steps:
+      # Be sure to checkout the code before downloading artifacts, or they will
+      # be overwritten
+      - name: Checkout code
+        if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
+        uses: actions/checkout@v4
+
+      - name: Download artifacts
+        if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
+        uses: actions/download-artifact@v3
+        with:
+          name: linux-latest
+          path: artifacts
+
+      - name: Login to Docker Hub
+        if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
+        uses: docker/login-action@v3
+        with:
+          username: ${{ vars.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Set up Docker Buildx
+        if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build and push images
+        if: ${{ env.HAS_DOCKER_CREDS == 'true' }}
+        env:
+          DOCKER_IMAGE_REPO: ${{ vars.DOCKER_IMAGE_REPO || 'nebulaoss/nebula' }}
+          DOCKER_IMAGE_TAG: ${{ vars.DOCKER_IMAGE_TAG || 'latest' }}
+        run: |
+          mkdir -p build/linux-{amd64,arm64}
+          tar -zxvf artifacts/nebula-linux-amd64.tar.gz -C build/linux-amd64/
+          tar -zxvf artifacts/nebula-linux-arm64.tar.gz -C build/linux-arm64/
+          docker buildx build . --push -f docker/Dockerfile --platform linux/amd64,linux/arm64 --tag "${DOCKER_IMAGE_REPO}:${DOCKER_IMAGE_TAG}" --tag "${DOCKER_IMAGE_REPO}:${GITHUB_REF#refs/tags/v}"
+
   release:
     name: Create and Upload Release
     needs: [build-linux, build-darwin, build-windows]

Makefile

@@ -22,6 +22,9 @@ ifndef BUILD_NUMBER
 	endif
 endif
 
+DOCKER_IMAGE_REPO ?= nebulaoss/nebula
+DOCKER_IMAGE_TAG ?= latest
+
 LDFLAGS = -X main.Build=$(BUILD_NUMBER)
 
 ALL_LINUX = linux-amd64 \
@@ -79,6 +82,8 @@ DOCKER_BIN = build/linux-amd64/nebula build/linux-amd64/nebula-cert
 
 all: $(ALL:%=build/%/nebula) $(ALL:%=build/%/nebula-cert)
 
+docker: docker/linux-$(shell go env GOARCH)
+
 release: $(ALL:%=build/nebula-%.tar.gz)
 
 release-linux: $(ALL_LINUX:%=build/nebula-%.tar.gz)
@@ -151,6 +156,9 @@ build/nebula-%.tar.gz: build/%/nebula build/%/nebula-cert
 build/nebula-%.zip: build/%/nebula.exe build/%/nebula-cert.exe
 	cd build/$* && zip ../nebula-$*.zip nebula.exe nebula-cert.exe
 
+docker/%: build/%/nebula build/%/nebula-cert
+	docker build . $(DOCKER_BUILD_ARGS) -f docker/Dockerfile --platform "$(subst -,/,$*)" --tag "${DOCKER_IMAGE_REPO}:${DOCKER_IMAGE_TAG}" --tag "${DOCKER_IMAGE_REPO}:$(BUILD_NUMBER)"
+
 vet:
 	go vet $(VET_FLAGS) -v ./...
 

docker/Dockerfile

@@ -0,0 +1,11 @@
+FROM gcr.io/distroless/static:latest
+
+ARG TARGETOS TARGETARCH
+COPY build/$TARGETOS-$TARGETARCH/nebula /nebula
+COPY build/$TARGETOS-$TARGETARCH/nebula-cert /nebula-cert
+
+VOLUME ["/config"]
+
+ENTRYPOINT ["/nebula"]
+# Allow users to override the args passed to nebula
+CMD ["-config", "/config/config.yml"]

docker/README.md

@@ -0,0 +1,24 @@
+# NebulaOSS/nebula Docker Image
+
+## Building
+
+From the root of the repository, run `make docker`.
+
+## Running
+
+To run the built image, use the following command:
+
+```
+docker run \
+    --name nebula \
+    --network host \
+    --cap-add NET_ADMIN \
+    --volume ./config:/config \
+    --rm \
+    nebulaoss/nebula
+```
+
+A few notes:
+
+- The `NET_ADMIN` capability is necessary to create the tun adapter on the host (this is unnecessary if the tun device is disabled.)
+- `--volume ./config:/config` should point to a directory that contains your `config.yml` and any other necessary files.

overlay/tun_linux.go

@@ -81,7 +81,24 @@ func newTunFromFd(c *config.C, l *logrus.Logger, deviceFd int, cidr *net.IPNet)
 func newTun(c *config.C, l *logrus.Logger, cidr *net.IPNet, multiqueue bool) (*tun, error) {
 	fd, err := unix.Open("/dev/net/tun", os.O_RDWR, 0)
 	if err != nil {
-		return nil, err
+		// If /dev/net/tun doesn't exist, try to create it (will happen in docker)
+		if os.IsNotExist(err) {
+			err = os.MkdirAll("/dev/net", 0755)
+			if err != nil {
+				return nil, fmt.Errorf("/dev/net/tun doesn't exist, failed to mkdir -p /dev/net: %w", err)
+			}
+			err = unix.Mknod("/dev/net/tun", unix.S_IFCHR|0600, int(unix.Mkdev(10, 200)))
+			if err != nil {
+				return nil, fmt.Errorf("failed to create /dev/net/tun: %w", err)
+			}
+
+			fd, err = unix.Open("/dev/net/tun", os.O_RDWR, 0)
+			if err != nil {
+				return nil, fmt.Errorf("created /dev/net/tun, but still failed: %w", err)
+			}
+		} else {
+			return nil, err
+		}
 	}
 
 	var req ifReq