deployment: multi-arch master images (#2896)

.github/workflows/docker-master.yaml

@@ -17,6 +17,9 @@ jobs:
         with:
           fetch-depth: 0
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
 
@@ -46,6 +49,7 @@ jobs:
           context: .
           file: ./Dockerfile
           push: true
+          platforms: linux/amd64,linux/arm64
           tags: ${{ steps.metadata.outputs.tags }}
           labels: |
             org.opencontainers.image.created=${{ steps.metadata.outputs.timestamp }}
@@ -58,6 +62,7 @@ jobs:
           context: .
           file: ./Dockerfile.debug
           push: true
+          platforms: linux/amd64,linux/arm64
           tags: pomerium/pomerium:debug
           labels: |
             org.opencontainers.image.created=${{ steps.metadata.outputs.timestamp }}

Dockerfile

@@ -1,3 +1,5 @@
+ARG ARCH=amd64
+
 FROM golang:latest as build
 WORKDIR /go/src/github.com/pomerium/pomerium
 
@@ -20,7 +22,7 @@ RUN apt-get update && apt-get install -y ca-certificates
 # Remove expired root (https://github.com/pomerium/pomerium/issues/2653)
 RUN rm /usr/share/ca-certificates/mozilla/DST_Root_CA_X3.crt && update-ca-certificates
 
-FROM gcr.io/distroless/base:debug
+FROM gcr.io/distroless/base:debug-${ARCH}
 ENV AUTOCERT_DIR /data/autocert
 WORKDIR /pomerium
 COPY --from=build /go/src/github.com/pomerium/pomerium/bin/* /bin/