Setting up CARP

You need the sysctls

$ sysctl net.inet.carp.allow
net.inet.carp.allow=1

$ sysctl net.inet.carp
net.inet.carp.allow=1
net.inet.carp.preempt=0
net.inet.carp.log=0
net.inet.carp.arpbalance=0

to let the magic work, we need

$ sudo sysctl net.inet.carp.preempt=1