Re: dependant services

From: Jonathan de Boyne Pollard <J.deBoynePollard-newsgroups_at_NTLWorld.com>
Date: Thu, 14 May 2015 23:25:08 +0100

Buck Evan:
> For example, I'd like to encode the fact that I don't expect service A to be able to come up before service B.

In nosh, the filesystem is the database. This is an ordering, not a
dependency. One can separately encode in nosh (a) that start of service
B will cause the start of service A, and (b) that start of service A has
to be scheduled after the start of service B rather than in parallel.
The latter is an ordering. And it's a symbolic link, either A/after/B
pointing to B or B/before/A pointing to A. The former is a symbolic link
B/wants/A pointing to A.

This is a very brief precis. There's a detailed explanation of service
bundles and all of the subdirectories in them in the manual. Start with
"man system-control". Or even "man manual/system-control.1" if you
haven't been brave enough to actually export the software into
/usr/local. (-:

The most widespread general purpose practice for "breaking" (i.e.
avoiding) this kind of ordering is of course opening server sockets
early. Client and server then don't need to be so strongly ordered.
Received on Thu May 14 2015 - 22:25:08 UTC