Glider Labs maintains an official Alpine Linux Docker image. We've just set
up a sponsorship with Fastly to provide CDN service for the Alpine Linux
package index. The mirror is default in our image. But can be used by
others to possibly speed up package installs where there is not a mirror
close to you.
The CDN endpoint is at http://alpine.gliderlabs.com/. It is setup to cache
packages for 2 weeks and to never cache the APKINDEX.tar.gz (which may
change in future to help with slow APKINDEX.tar.gz downloads). It uses
http://nl.alpinelinux.org/ as primary origin server and
http://dl-4.alpinelinux.org/ if the primary should fail.
In the future I hope to configure Fastly Shielding feature to send cache
MISSes to the closest mirror instead of http://nl.alpinelinux.org/. If you
try out this mirror please let me know how it works out for you and if you
have any feedback.