Base image version (debian stretch, ubuntu bionic)

[andriy-f]

Hi, just curious

1. Did you have any reasons not to use Debian Stretch or Ubuntu bionic (18 LTS) for MongoDB 4?

2. In Dockerfile you sometimes use

set -ex \
  command1; \
  command2; \

and sometimes

set -x \
  command1 &&
  command2 

what's the benefit of one over other if applicable?

[andriy-f]

#275
#297

[yosifkit]

We did try to update to bionic (#293) but lost architectures and so reverted it with #297. We moved to Ubuntu from Debian based images to get more architecture support.

As for the reason for ampersand versus semicolon on the RUN line, shells have unwanted behavior with something like a for loop within a complex expression (&& chain) but the rest of the time it is basically equivalent. As specific parts are updated, we've been slowly moving toward the semicolon version with set -e, but it is not worth rebuilding the image for what is mostly a stylistic change.

[andriy-f]

Thanks @yosifkit