LXD and keepalived

I have lxd on snap, two containers with keepalived and 1 floating IP.
I’m wondering is there any way to reserve ip address used in keepalived which is floating to be sure
that it will not be assigned to any other container in the future by dhcp server.

There’s no way to reserve an address but you can change the DHCP range to give yourself a bunch of addresses which aren’t used for DHCP.