virsh domifaddr domain does not show static IP

[Kaushal Shriyan]

On Fri, Sep 10, 2021 at 12:08 AM Laine Stump <laine at redhat.com> wrote:

>
>
> On 9/9/21 2:11 PM, Kaushal Shriyan wrote:
> > Hi,
> >
> > I have assigned static IP for all the below KVM Guest VM's. Is there a
> > way to find out the IP of the below VM's from virsh utility or any
> > other utility? virsh domifaddr testdobssbahrainms does not show the
> > static IP.
>
> By default, "virsh domifaddr" will attempt to lookup the MAC address of
> the guest interface in the table of IP addresses leased from the
> libvirt-managed dhcp server for the network the interface is connected
> to. If the interface has a statically configured IP, or if it isn't
> connected to a libvirt-managed virtual network, then no IP addresses
> will be found. You can change this behavior with the "--source" option:
>
>     '--source arp'  - looks for the MAC address in the host's ARP table
>     '--source agent' - queries the guest agent (which must have been
>                        installed)
>
> Each of these has varying levels of reliability and success, depending
> on your specific setup. e.g., if the guests don't have the guest agent
> installed, that method will fail, and if the guest can't be trusted,
> then any information it sends also can't be trusted. Alternately, it is
> possible for an external device on the network to poison the ARP table
> with bad information, and it's also possible that the guest simply has
> no entry in the ARP table (if the host has never attempted to
> communicate with it, or if it's connected via a host interface/bridge
> that itself has no IP address.)
>
> Hmm, and I guess --source arp also wouldn't work for guests connected
> via macvtap (<interface type='direct'>) since guest<->host communication
> isn't supported in that case (and so the guest could never show up in
> the host's ARP table).
>
> Anyway if your guests are connected to a libvirt virtual network or to a
> Linux host bridge that has an IP address on the host, then "--source
> arp" should work for you.
>
> >
> > # virsh list --all
> >   Id   Name                      State
> > -----------------------------------------
> >   1    testdobssbahrainms         running
> >   2    testdosstomcatpibms       running
> >   3    testdobsstomcatkineticms   running
> >   4    testdobsstomcatmsbms       running
> >   5    testdobsstomcatfdms        running
> >   6    testdobsstomcathsbcnetms   running
> >   7    testdobsstomcatdbbms       running
> >   8    testdobssapigeedev         running
> >
> > #
> > # virt-install --version
> > 2.2.1
> > # cat /etc/redhat-release
> > CentOS Stream release 8
> >
> > #virsh domifaddr testdobssbahrainms
> > #Name       MAC address          Protocol     Address
> >
> -------------------------------------------------------------------------------
> >
> > Please guide. Thanks in advance.
> >
> > Best Regards,
> >
> > Kaushal
> >
> >


Thanks Laine for the detailed explanation. The below command worked. Thanks
a lot and appreciate it.

virsh domifaddr testdobssbahrainms --source agent

Name       MAC address          Protocol     Address
-------------------------------------------------------------------------------
 lo         00:00:00:00:00:00    ipv4         127.0.0.1/8
 eth0       52:14:00:74:11:14    ipv4         192.168.0.113/24

Is there a way to find out the Static IP address if the KVM Guest VM
instance is shut off? Thanks in advance.

Best Regards,

Kaushal
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