However, the install step fails as the package isn’t available:
Package chromium-browser is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'chromium-browser' has no installation candidate
I can’t quite figure out why the package can’t be located; do the default environments exclude some of the regular package repositories? Is there a repository we need to add?
As per usual, right after posting this I realized the problem: in Debian the package name is just chromium and not chromium-browser. Once I corrected that the builds started working, so it looks like the package manager in Ubuntu 14.04 environments really does use the Debian packages instead of Ubuntu’s. I just wasn’t aware of that.
Yep. If you go into your build list, click on the most recent failed build, then use “Rebuild with SSH” in the top right-hand corner. Wait for it to finish and then it will give you SSH details you can use to get a post-failure console. It’s very handy for debugging generally.
Just bear in mind it eats build minutes, and if you’re short on minutes, it is a good idea to cancel the job manually rather than disconnecting and waiting for it to timeout.