The default mirror broken?
$ docker build . --network host
Sending build context to Docker daemon 234.5MB
Step 1/24 : FROM golang:1.17-alpine AS builder
---> da4596da1948
Step 2/24 : RUN apk --update add ca-certificates git make g++
---> Running in 142c1e966ed9
fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/main/x86_64/APKINDEX.tar.gz
ERROR: https://dl-cdn.alpinelinux.org/alpine/v3.14/main: temporary error (try again later)
WARNING: Ignoring https://dl-cdn.alpinelinux.org/alpine/v3.14/main: No such file or directory
fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/community/x86_64/APKINDEX.tar.gz
ERROR: https://dl-cdn.alpinelinux.org/alpine/v3.14/community: temporary error (try again later)
WARNING: Ignoring https://dl-cdn.alpinelinux.org/alpine/v3.14/community: No such file or directory
ERROR: unable to select packages:
g++ (no such package):
required by: world[g++]
git (no such package):
required by: world[git]
make (no such package):
required by: world[make]
The command '/bin/sh -c apk --update add ca-certificates git make g++' returned a non-zero code: 3