Outages or mis-configurations can happen to pretty much any source of packages you use, be it debian, pypi, npm, bower or maven repositories, or source control.

Outages or mis-configurations can happen to pretty much any source of packages you use, be it debian, pypi, npm, bower or maven repositories, or source control. Anybody remember left-pad? So as soon as you depend heavily on external sources, you should start to think about maintaining your own mirror. Software like pulp and nexus are pretty versatile, and give you a good amount of control over your upstream sources.