[Openstack-operators] [neutron][cinder] Just some questions?
blak111 at gmail.com
Mon Jun 29 20:26:23 UTC 2015
Not sure about the cinder question, but I can answer the Neutron ones.
>When dnsmasq DHCP leases expire with a still-active VM, how does dnsmasq
know to renew the same IP address to the same machine and what changes to
ensure the IP can be re-assigned?
Dnsmasq is configured by the DHCP agent with static leases for all of the
created Neutron ports. It will only give out leases for a known IP/mac
pair. It's not configured like a regular DHCP server that has a pool it
allocates from so you don't have to worry about an address being taken by
>When overlapping IP's/namespaces are enabled within Neutron with a VLAN
model, what do the packets look like on the switch when the compute and
network nodes are installed on separate machines?
Traffic leaving the VM will be tagged with the VLAN for each network. Since
the traffic stays isolated within the VLAN, you would see the same IP
addresses on different VLAN tags. When this traffic arrives at the network
node, the vswitch will tag the tag off and put the packet onto the
corresponding internal VLAN (or bridge in the linuxbridge case), which has
the ports for the correct L3 namespace.
On Mon, Jun 29, 2015 at 12:38 PM, Adam Lawson <alawson at aqorn.com> wrote:
> I had just a few questions that came up during a class recently and I
> didn't have an answer. Can someone confirm these?
> 1. Does a VM using a particular volume need to be off in order for
> cinder-backup to take a snapshot?
> 2. When dnsmasq DHCP leases expire with a still-active VM, how does
> dnsmasq know to renew the same IP address to the same machine and what
> changes to ensure the IP can be re-assigned?
> 3. When overlapping IP's/namespaces are enabled within Neutron with a
> VLAN model, what do the packets look like on the switch when the compute
> and network nodes are installed on separate machines?
> *Adam Lawson*
> AQORN, Inc.
> 427 North Tatnall Street
> Ste. 58461
> Wilmington, Delaware 19801-2230
> Toll-free: (844) 4-AQORN-NOW ext. 101
> International: +1 302-387-4660
> Direct: +1 916-246-2072
> OpenStack-operators mailing list
> OpenStack-operators at lists.openstack.org
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