tl;dr: In order to improve our osx10.6 test capacity and to quickly start osx10.9 testing, we’re planning to make the following changes to our OSX-build-and-test-infrastructure.
1) convert all 10.7 test machines as 10.6 test machines in order to increase our 10.6 capacity. Details in bug#942299.
2) convert all 10.8 test machines as 10.9 test machines.
3) do most 10.7 builds as osx-cross-compiling-on-linux-on-AWS, repurpose 10.7 builder machines to be additional 10.9 test machines. This cross-compiler work is ongoing, it will take time to complete, and it will take time to transition into production, hence, it is listed last in this list. The curious can follow bug#921040.
Each of these items are large stand-alone projects involving the same people across multiple groups, so we’ll roll each out in the aforementioned sequence.
1) Removing specific versions of an OS from our continuous integration systems based on vendor support and/or usage data is not a new policy. We have done this several times in the past. For example, we have dropped WinXPsp0/sp1/sp2 for WinXPsp3; dropped WinVista for Win7; dropped Win7 x64 for Win8 x64; and soon we will drop Win8.0 for Win8.1; …
** Note for the record that this does *NOT* mean that Mozilla is dropping support for osx10.7 or 10.8; it just means we think *automated* testing on 10.6,10.9 is more beneficial.
2) To see Firefox’s minimum OS requirements see: https://www.mozilla.org/en-US/firefox/25.0.1/system-requirements
3) Apple is offering osx10.9 as a free upgrade to all users of osx10.7 and osx10.8. Also, note that 10.9 runs on any machine that can run 10.7 or 10.8. Because the osx10.9 release is a free upgrade, users are quickly upgrading. We are seeing a drop in both 10.7 and 10.8 users and in just a month since the 10.9 release, we already have more 10.9 users than 10.8 users.
4) Distribution of Firefox users from the most to the least (data from 15-nov-2013):
10.6 – 34%
10.7 – 23% – slightly decreasing
10.8 – 21% – notably decreasing
10.9 – 21% – notably increasing
more info: http://armenzg.blogspot.ca/2013/11/re-thinking-our-mac-os-x-continuous.html
5) Apple is no longer providing security updates for 10.7; any user looking for OS security updates will need to upgrade to 10.9. Because OSX10.9 is a free upgrade for 10.8 users, we expect 10.8 to be in similar situation soon.
6) If a developer lands a patch that works on 10.9, but it fails somehow on 10.7 or 10.8, it is unlikely that we would back out the fix, and we would instead tell users to upgrade to 10.9 anyways, for the security fixes.
7) It is no longer possible to buy any more of the 10.6 machines (known as revision 4 minis), as they are long desupported. Recycling 10.7 test machines means that we can continue to support osx10.6 at scale without needing to buy/rack/recalibrate test and performance results.
8) Like all other large OS changes, this change would ride the trains. Most 10.7 and 10.8 test machines would be reimaged when we make these changes live on mozilla-central and try, while we’d leave a few behind. The few remaining would be reimaged at each 6-week train migration.
If we move quickly, this reimaging work can be done by IT before they all get busy with the 650-Castro -> Evelyn move.
For further details, see armen’s blog http://armenzg.blogspot.ca/2013/11/re-thinking-our-mac-os-x-continuous.html. To make sure this is not missed, I’ve cross-posted this to dev.planning, dev.platform and also this blog. If you know of anything we have missed, please reply in the dev.planning thread.
[UPDATED 29-nov-2013 with link to bug#942299, as the 10.7->10.6 portion of this work just completed.]