Specify the Version Number of Absolutely Everything

Lock your OS version number

Vagrant told me that there was a newer version of the ubuntu/xenial image that I was using. I updated it and ran vagrant up and it died citing

Temporary failure resolving 'archive.ubuntu.com'

I took this literally at first and tried adding Google’s DNS ( to the box but that didn’t fix it. After trying some other stuff and getting nowhere I reverted back to the OS version I had been using before I upgraded and everything started working again.

I was able to tell the version I had been on by checking the list of images that Vagrant had downloaded by running vagrant box list. I was then able to dictate the version that should be used by adding the following line to my Vagrantfile:

config.vm.box_version = "20160815.0.0"

This ensures that going forwards a version known to work will be downloaded, and I can update at my convenience.

Presumably the actual problem was a compatibility issue between VirtualBox and that version of Ubuntu, possibly specifically an issue with VirtualBox Guest Additions and the networking in some way. I was more focused on getting everything working than really hunting down the cause of the problem at the time, so we’ll never know. As the title says, lock down your version numbers for everything or you’ll be hit by surprise compatibility issues.