Make the server names nginx hash size configurable

And default it to 64, instead of relying on nginx's poor cache line logic. By making it a config, people can set it higher if they need to.

Fixes https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1249

CPUs with smaller cache lines will have slightly worse performance, but we don't actually expect to be run on those cpus anyways. 64 should be fine for the pi2. 32 would have been ideal for a pentium 3.

@twk3 please add to changelog and to the the docs explaining what is the problem and solution.

Reassigned to @twk3

Added 1 commit:

• 612973a9 - Add changelog entry for the nginx server name bucket size config change

Added 16 commits:

• 612973a9...5d16283e - 14 commits from branch master
• ce2afa8d - Make the server names nginx hash size configurable
• 0208f984 - Add changelog entry for the nginx server name bucket size config change

Added 1 commit:

• 4a675cee - Add bucket size error to troubleshooting docs

Added 1 commit:

• 68513cc9 - Add bucket size error to troubleshooting docs

Added 1 commit:

• c172c90b - Add bucket size error to troubleshooting docs

Links are hard.

Changelog entry and docs added

Reassigned to @marin

Status changed to merged