Setting BIRD up for uninterrupted package upgrades

[Matt Dupre (projectcalico.org)]

Hi all,

I'm working on Project Calico (http://www.projectcalico.org/), where we've been using BIRD as a BGP Router.  We'd like to be able to set BIRD up such that we can upgrade the package in future without removing any routes.  Does anyone have a good way to do this - we're using Ubuntu 14.04 (upstart) and RHEL 7.1 (systemd)?

I've got graceful restart configured (`graceful restart;` in the protocols and `-R` on the command line), and this works great for unexpected restarts (such as segfaults) - upstart / systemd restarts BIRD and it resumes normal operation without removing any routes.  We've considered modifying the job/service to kill BIRD instead of stopping it gracefully (for example as a pre-stop command), but I'm just wondering if there's a better way. 

Kind regards,
Matt