When I migrate a virtual machine (VM), the gateway of the VM must be reconfigured to communicate with the outside. So I decided to use
DHCP to reconfigure the gateway of the VM. If once the VM sends a
DHCPDISCOVERY after the migration, a
DHCP server can indicate the valid gateway IP for the VM. I will then change the configuration of the
DHCP server before the migration.
If I can use
dhclient or any other tool that is running inside the VM, the solution will be obvious. But there are some restriction in which I can't run any commands under the VM. I must deal with the VM externally. Are there any kinds of tools which could force the VM to do
DHCPDISCOVERY? Any other potential solutions?
ps. 'migration' is 'live migration'. What i want to achieve is seamless service.
add : Why i reached this question. Maybe this can show hidden requirement or restriction which are not shown in my pool question. My first approach was NAT with central machine. All host machine attached to this central machine. With this approach i could achieve what i want. freely migrate through any machine in the cluster. It's not literally seamless, but in my requirement, it's quite enough. But with this approach, I can't scale out cluster and there can be terrible single point of failure on the central machine. So my recent approach was dividing NAT function to the each hosts. In this approach, i have to set gateway of each host to virtual bridge of each machine. My servefault question has arose from this environment. What if i have to do host-to-host migration? After live migration, i have to set new gate way to the vm. Because gateway information varies with each host. Next was my server fault question. Though i'm currently using KVM full virtualization(for window supports). But I'm also looking for xen or paravirutualization solution. I'm not sure, but currently it looks like paravirtualization or ovs, flud-light can solve the issue. (After i wrote this, i have realized that i should write new question. maybe it is more fit for my source problem)