Title: How to parallelize Drist

	Title: How to parallelize Drist
	Author: Solène
	Date: 06 February 2019
	Tags: drist automation unix
	Description:

	This article will show you how to make drist faster by using it on
	multiple
	servers at the same time, in a correct way.

	[What is
	drist?](https://dataswamp.org/~solene/2018-11-29-drist-intro.html)

	It is easily possible to parallelize drist (this works for everything
	though)
	using Makefile. I use this to deploy a configuration on my servers at
	the same
	time, this is way faster.

	A simple BSD Make compatible Makefile looks like this:

	SERVERS=tor-relay.local srvmail.tld srvmail2.tld
	${SERVERS}:
	drist $*
	install: ${SERVERS}
	.PHONY: all install ${SERVERS}

	This create a target for each server in my list which will call drist.
	Typing
	`make install` will iterate over `$SERVERS` list but it is so possible
	to use
	`make -j 3` to tell make to use 3 threads. The output may be mixed
	though.

	You can also use `make tor-relay.local` if you don't want make to
	iterate over
	all servers. This doesn't do more than typing `drist tor-relay.local`
	in the
	example, but your Makefile may do other logic before/after.

	If you want to type `make` to deploy everything instead of `make
	install` you
	can add the line `all: install` in the Makefile.

	If you use GNU Make (gmake), the file requires a small change:

	The part `${SERVERS}:` must be changed to `${SERVERS}: %:`, I think
	that gmake
	will print a warning but I did not succeed with better result. If you
	have the
	solution to remove the warning, please tell me.

	If you are not comfortable with Makefiles, the .PHONY line tells make
	that
	the targets are not valid files.

	Make is awesome!