How to parallelize Drist

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?

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!