Current container images are fairly large (441Mb) because they contains Go-Lang build

Two possibilities: Simple <a href="https://docs.docker.com/bui

fixed in <a class="commit-link" data-hovercard-type="commit" data-hovercard-url="https

Smaller container images,about purestorage-openconnect/pure-fa-openmetrics-exporter

Comments (3)

finkr commented on July 18, 2024

Two possibilities:

Simple multistage image, using alpine as base image, includes apk and shell (21Mb)
Statically compiled with empty base image (scratch), in the spirit of distroless, (14Mb).

Simple multistage

FROM golang:alpine as build

WORKDIR /usr/src/app

# pre-copy/cache go.mod for pre-downloading dependencies and only redownloading them in subsequent builds if they change
COPY go.mod go.sum ./
RUN go mod download && go mod verify

COPY . .
RUN go build -v -o /usr/local/bin/pure-fa-om-exporter cmd/fa-om-exporter/main.go

FROM alpine
COPY --from=build  /usr/local/bin/pure-fa-om-exporter /usr/local/bin/pure-fa-om-exporter
EXPOSE 9490
ENTRYPOINT ["/usr/local/bin/pure-fa-om-exporter"]
CMD ["--host", "0.0.0.0", "--port", "9490"]

$ docker history pure-fa-om-exporter 
IMAGE                CREATED BY                                      SIZE      COMMENT
51d99b9251e5   /bin/sh -c #(nop) CMD ["--host" "0.0.0.0" "…   0B        
353a48112424   /bin/sh -c #(nop) ENTRYPOINT ["/usr/local/b…   0B        
d2a24d618855   /bin/sh -c #(nop) EXPOSE 9490                  0B        
1ca44db4f499   /bin/sh -c #(nop) COPY file:30dad3c48b73c1a1…   13.6MB    
042a816809aa   /bin/sh -c #(nop) CMD ["/bin/sh"]              0B        
<missing>      /bin/sh -c #(nop) ADD file:e4d600fc4c9c293ef…   7.05MB

Statically compiled (14Mb)

Go-lang compilation options for static build are inspired by prometheus/node-exporter.

Some projects also provides container with a shell (typically busybox)

FROM golang:alpine as build

WORKDIR /usr/src/app

# pre-copy/cache go.mod for pre-downloading dependencies and only redownloading them in subsequent builds if they change
COPY go.mod go.sum ./
RUN go mod download && go mod verify

COPY . .
RUN CGO_ENABLED=1 go build -a -tags 'netgo osusergo static_build' -v -o /usr/local/bin/pure-fa-om-exporter cmd/fa-om-exporter/main.go

FROM scratch
#FROM busybox:musl
COPY --from=build  /usr/local/bin/pure-fa-om-exporter /pure-fa-om-exporter
EXPOSE 9490
ENTRYPOINT ["/pure-fa-om-exporter"]
CMD ["--host", "0.0.0.0", "--port", "9490"]

$ docker history d6274a0aaee5
IMAGE          CREATED BY                                      SIZE      COMMENT
d6274a0aaee5   /bin/sh -c #(nop) CMD ["--host" "0.0.0.0" "…   0B        
7a04a959cb79   /bin/sh -c #(nop) ENTRYPOINT ["/pure-fa-om-…   0B        
3bb9c2a0527f   /bin/sh -c #(nop) EXPOSE 9490                  0B        
03bae96ab57e   /bin/sh -c #(nop) COPY file:4774cc7a4b571ef1…   13.5MB

from pure-fa-openmetrics-exporter.