`docker build`: prevent cache invalidation
for some unknown reason docker build
does not cache apt-get update && apt-get install foo
, for example, in dockerfiles/Docker.postgres
. This is very annoying!
=> [1/10] FROM docker.io/library/postgres:9.6@sha256:b5f6e8a1369ec3ce48c8419c65dffa083c3eb4a507cb8 0.0s
=> CACHED [2/10] COPY apt.local.conf /etc/apt/apt.conf.d/99local.conf 0.0s
=> [3/10] RUN apt-get update && apt-get upgrade 5.1s
=> [4/10] RUN apt-get update && apt-get install git 13.7s