[Dev] Jenkins: transition to new x86 build machine

[nurupo]

Hello,

This is follow up to the similar email from June. Last time we were 
transitioning x86-64 build machine, now we transition x86 build machine.

Since the build machines on our build server (https://build.tox.chat) 
are underutilized, we are transitioning from using a build machine that 
is always online to a build machine that would be created automatically 
on demand. This is supposed to reduce how much we pay for build 
machines. It also has other benefits, such as a fully documented setup 
of the build machine and the fact that the on-demand build machine is 
always recreated off a base image, without retaining any build state.

Currently we are transitioning the x86 build machine. The on-demand 
build machine was set up from scratch, so it might be missing packages 
or configuration files that are present on the 24/7 online build 
machine. Because of this, we have set up a test on-demand build machine 
that you can run your build jobs on, to give you a chance to see and 
report any issues with the on-demand build machine before we transition. 
We plan for the transition to take place in a month from now, on January 
19th, unless we find any issues during the testing. To run your build 
job on the test on-demand build machine, restrict it to run on a node 
labeled "test-linux-x86.slave.tox.chat". If the on-demand build machine 
is not online when you trigger the build job, it should come online in 
about 5 to 12 minutes. Email me any issues you find during your test of 
the on-demand build machine.

-- 
Regards,
nurupo