How to Shrink Go Docker Images from 1GB to 16MB: Multi‑Stage Build Tips

1. Direct compilation (22 MB binary)

Compile the Go source for Linux on the host and copy the resulting binary into a minimal container.

set GOOS=linux
set GOARCH=amd64
go build main.go

The resulting image contains only the 22 MB executable.

2. Run source without compilation (≈941 MB)

Use the official golang image, copy the source code, and let the container execute go run at startup.

# Base image
FROM golang
MAINTAINER scoful
WORKDIR $GOPATH/kingProject
COPY . $GOPATH/kingProject
ENV GOPROXY https://goproxy.cn,direct
EXPOSE 8888
VOLUME ["/go/kingProject/config","/go/kingProject/log"]
ENTRYPOINT ["go","run","main.go"]

The image size is roughly the same as the base golang image (≈941 MB) and startup is slow because compilation happens at runtime.

3. Compile inside the image (≈1.14 GB)

Build the binary during the image build and run the compiled binary.

# Base image
FROM golang
MAINTAINER scoful
WORKDIR $GOPATH/kingProject
COPY . $GOPATH/kingProject
ENV GOPROXY https://goproxy.cn,direct
RUN GOOS=linux GOARCH=amd64 go build main.go
EXPOSE 8888
VOLUME ["/go/kingProject/config","/go/kingProject/log"]
ENTRYPOINT ["./main"]

The image grows to 1.14 GB because all Go dependencies are cached inside the image, but the container starts instantly.

4. Use an Alpine base (≈517 MB)

Switch the base image to golang:alpine, which is a minimal distribution.

# Base image
FROM golang:alpine
MAINTAINER scoful
WORKDIR $GOPATH/kingProject
COPY . $GOPATH/kingProject
ENV GOPROXY https://goproxy.cn,direct
RUN GOOS=linux GOARCH=amd64 go build main.go
EXPOSE 8888
VOLUME ["/go/kingProject/config","/go/kingProject/log"]
ENTRYPOINT ["./main"]

The image size drops to 517 MB, about a 56 % reduction.

5. Multi‑stage build with Alpine runner (≈28.4 MB)

Separate the build environment (golang:alpine) from the runtime environment (plain Alpine) and copy only the compiled binary and needed config.

# Builder stage
FROM golang:alpine AS builder
MAINTAINER scoful
WORKDIR /go/kingProject
COPY . /go/kingProject
ENV GOPROXY https://goproxy.cn,direct
RUN GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build main.go

# Runner stage
FROM alpine AS runner
WORKDIR /go/kingProject
COPY --from=builder /go/kingProject/main .
COPY --from=builder /go/kingProject/config ./config
EXPOSE 8888
VOLUME ["/go/kingProject/config","/go/kingProject/log"]
ENTRYPOINT ["./main"]

The resulting image is only 28.4 MB.

6. Multi‑stage with Scratch runner (≈22.8 MB)

Replace the Alpine runtime with the empty scratch image to eliminate all unnecessary layers.

# Builder (same as step 5)
FROM golang:alpine AS builder
... (same build commands) ...

# Runner
FROM scratch AS runner
WORKDIR /go/kingProject
COPY --from=builder /go/kingProject/main .
COPY --from=builder /go/kingProject/config ./config
EXPOSE 8888
VOLUME ["/go/kingProject/config","/go/kingProject/log"]
ENTRYPOINT ["./main"]

The image shrinks to 22.8 MB, but a scratch container cannot be inspected with typical tools (no shell, no exec).

7. Strip binary symbols (≈16.3 MB)

Add -ldflags="-w -s" to the build command to remove debug information.

RUN GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -ldflags="-w -s" main.go

The final image size becomes 16.3 MB, a further 29 % reduction.

8. Final version with timezone configuration (still 16.3 MB)

Include a few extra RUN steps to set the container’s timezone to Asia/Shanghai.

RUN echo "https://mirrors.aliyun.com/alpine/v3.8/main/" > /etc/apk/repositories \
    && echo "https://mirrors.aliyun.com/alpine/v3.8/community/" >> /etc/apk/repositories \
    && apk add --no-cache tzdata \
    && cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime \
    && echo Asia/Shanghai > /etc/timezone \
    && apk del tzdata

The image size remains 16.3 MB while the container now reports the correct timezone.

9. Recommended recipe (Alpine runner, ≈21.9 MB)

Combine the multi‑stage approach with an Alpine runtime (instead of scratch) to keep the image small yet still usable for debugging.

# Builder
FROM golang:alpine AS builder
MAINTAINER scoful
WORKDIR /go/kingProject
COPY . /go/kingProject
ENV GOPROXY https://goproxy.cn,direct
RUN GOOS=linux GOARCH=amd64 CGO_ENABLED=0 go build -ldflags="-w -s" main.go

# Runner (Alpine)
FROM alpine AS runner
WORKDIR /go/kingProject
COPY --from=builder /go/kingProject/main .
COPY --from=builder /go/kingProject/config ./config
# Set timezone
RUN echo "https://mirrors.aliyun.com/alpine/v3.8/main/" > /etc/apk/repositories \
    && echo "https://mirrors.aliyun.com/alpine/v3.8/community/" >> /etc/apk/repositories \
    && apk add --no-cache tzdata \
    && cp /usr/share/zoneinfo/Asia/Shanghai /etc/localtime \
    && echo Asia/Shanghai > /etc/timezone \
    && apk del tzdata
EXPOSE 8888
VOLUME ["/go/kingProject/config","/go/kingProject/log"]
ENTRYPOINT ["./main"]

This configuration yields an image of about 21.9 MB, offering a good balance between minimal size and operability.

In summary, while scratch produces the tiniest image, its lack of utilities makes it impractical for most real‑world scenarios; the Alpine‑based multi‑stage build is therefore the recommended approach.