Support multi-arch

Dockerfile

@@ -1,13 +1,27 @@
-FROM golang:1.11.6-stretch as golang
+ARG BUILDPLATFORM=linux/amd64
+
+FROM --platform=$BUILDPLATFORM golang:1.11.6-stretch as golang
 WORKDIR /go/src/github.com/buoyantio/bb
 ADD .  /go/src/github.com/buoyantio/bb
 
 RUN mkdir -p /out
 RUN ./bin/dep ensure
-RUN go build -o /out/bb .
+ARG TARGETARCH
+RUN GOOS=linux GOARCH=$TARGETARCH go build -o /out/bb .
+
+FROM debian:buster-20200514-slim
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    curl \
+    dnsutils \
+    iptables \
+    jq \
+    nghttp2 \
+    ca-certificates \
+    && rm -rf /var/lib/apt/lists/*
+
+# We still rely on old iptables-legacy syntax.
+RUN update-alternatives --set iptables /usr/sbin/iptables-legacy \
+    && update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy
 
-FROM gcr.io/linkerd-io/base:2019-02-19.01
-RUN apt-get update
-RUN apt-get install -y ca-certificates
 COPY --from=golang /out /out
 ENTRYPOINT ["/out/bb"]

README.md

@@ -124,3 +124,18 @@ You can then use `curl`to query the service:
 
     $ curl `minikube -n bb-readme service bb-readme-gateway-svc  --url`
     {"requestUid":"in:http-sid:point-to-point-channel-grpc:-1-h1:8080-66349706","payload":"BANANA"}
+
+## Build Multi-Arch Images with Buildx
+
+Create the builder instance:
+
+    docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
+    docker buildx create --name=multiarch-builder --driver=docker-container --use
+    docker buildx inspect multiarch-builder --bootstrap
+
+Build the images:
+
+    docker buildx build . \
+      --platform linux/amd64,linux/arm64,linux/arm/v7 \
+      --push \
+      --tag buoyantio/bb:<version>