Upcoming changes in Linux build infrastructure on Travis CI

[PeterBowman]

We moved on to container-based (sudo: false) builds on Travis as a result of #48. The other alternative is virtualized builds (sudo: required). There is an ongoing transition process to migrate projects from the former to the latter. Soon, all sudo: false configs will be disregarded and treated as sudo: required.

https://blog.travis-ci.com/2018-10-04-combining-linux-infrastructures

Starting in the second week of November (we’ll post another blog post), we will start to migrate repositories that use sudo: false to the virtual machine-based infrastructure.

[jgvictores]

Not much to do here, right?

[PeterBowman]

Just make sure that we can follow this transition smoothly and update our .travis.yml everywhere (hence the "tracking" label).

[PeterBowman]

Despite being close to the final term (mid-November), the information is too scarce for now, so I'd wait for the next blog post they promised. Docs are still to be updated, but there is a short note at https://docs.travis-ci.com/user/reference/overview/#for-a-particular-travisyml-configuration:

Between middle of October 2018 and end December 2018 the default infrastructure your builds runs on will depend on a few different factors while we consolidate everything onto sudo-enabled virtual machines.

[PeterBowman]

https://blog.travis-ci.com/2018-11-19-required-linux-infrastructure-migration

In the next phase of the migration, all builds will run on virtual-machine-based infrastructure – regardless of the configuration for sudo in the .travis.yml. If you currently specify sudo: false in your .travis.yml, we recommend removing that configuration soon.

The timeline for this migration will be as follows:

• 19 November, 2018 - Today we publish this post and are ready to answer all your questions!
• 28 November, 2018 - We will send a service email to remind folks still using sudo: false on recent builds to remind you to migrate.
• 03 December, 2018 - We will start randomly sampling projects on both travis-ci.org and travis-ci.com to move them permanently to using the virtual-machine-based infrastructure for all builds. The projects will be migrated incrementally over a few days
• 07 December, 2018 - All projects that use a Linux build environment will be fully migrated to using the same Linux infrastructure, which runs builds in virtual-machines.

[PeterBowman]

Looks like sudo: required builds can transition smoothly. Most repos had been already migrated to sudo: false with #48. I'm definitely removing this line per:

If you currently specify sudo: false in your .travis.yml, we recommend removing that configuration soon.

Edit: bad wording, should have said that sudo: false builds can be phased out now that VMs are the default (sudo enabled). On Windows images (#51), sudo is not available (yet?), hence in the future we could transition more easily to this SO.