Hi I am having a few problems with DHCP leases from Virtual Router (CloudStack 4.2 / Basic Zone / XenServer) and wondered if this is a known problem.
Under normal circumstances everything is working fine, but occasionally a running instance does not get its assigned IP address via DHCP: tcpdump tells me the new instance is issuing a DHCPDISCOVER and getting no response. Looking at the Dnsmasq logs on the VR it seems that the DHCP server is declining to respond to the DHCPDISCOVER because the configured IP address is leased to another MAC (this MAC is associated with the NIC of a long-since-dead instance). Flushing the cache of existing leases in Dnsmasq by restarting the service seems to fix the problem (for some definition of "fix"). As Dnsmasq appears to be configured in /etc/dhcphosts.txt to issue infinite leases can someone tell me how leases get cleaned up if there is an abnormal termination of an instance such that it cannot send a DHCPRELEASE on shutdown? Thanks Simon
