On 03/04/16 18:01, Rick Stevens wrote:
On 03/04/2016 01:38 PM, Bob Goodwin
wrote:
I have two Fedora-23 computers
running virtual machine manager, this
one
connects to my ethernet LAN and
connects to the internet, the second
one, I've just set up connects to the
LAN but not the internet,
something is wrong with VMM
configuration.
Are both of these machines you're
talking about acting as hosts for
virtual machines?
.
Both F23 boxes have vmm running in them.
The ifconfig data is from Centos7 in the
VM's rather than the host machine.
This one, the working one shows:
[bobg@localhost ~]$ ifconfig
eth0:
flags=4163<UP,BROADCAST,RUNNING,MULTICAST>
mtu 1500
inet 192.168.122.30 netmask
255.255.255.0 broadcast
192.168.122.255
inet6
fe80::5054:ff:fe65:23a6 prefixlen 64
scopeid 0x20<link>
ether 52:54:00:65:23:a6
txqueuelen 1000 (Ethernet)
RX packets 162 bytes 11984
(11.7 KiB)
RX errors 0 dropped 0
overruns 0 frame 0
TX packets 89 bytes 11226
(10.9 KiB)
TX errors 0 dropped 0
overruns 0 carrier 0 collisions 0
That is an odd IP address to see on
eth0 on a virtual machine _host_.
I'd expect a virtual machine _guest_
to have an eth0 address on that
192.168.122 network.
192.168.122 is typically used by the
libvirt mechanism to provide IP
addresses to virtual machines. libvirt
runs a DHCP server offering IPs
on the 192.168.122 network to the
virtual machines running under it.
Be that as it may, since the IP is on
eth0, it's valid and your router
is NATting it and allowing you out to
the internet.
lo: flags=73<UP,LOOPBACK,RUNNING>
mtu 65536
inet 127.0.0.1 netmask
255.0.0.0
inet6 ::1 prefixlen 128
scopeid 0x10<host>
loop txqueuelen 0 (Local
Loopback)
RX packets 20 bytes 1716
(1.6 KiB)
RX errors 0 dropped 0
overruns 0 frame 0
TX packets 20 bytes 1716
(1.6 KiB)
TX errors 0 dropped 0
overruns 0 carrier 0 collisions 0
This is what I see in the other one
that does not connect:
[bobg@localhost ~]$ ifconfig
eth0:
flags=4163<UP,BROADCAST,RUNNING,MULTICAST>
mtu 1500
ether 52:54:00:c8:72:84
txqueuelen 1000 (Ethernet)
RX packets 39 bytes 2028
(1.9 KiB)
RX errors 0 dropped 0
overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0
overruns 0 carrier 0 collisions 0
Note that eth0 does NOT have an IP
address, so it can't do anything on
the LAN (or the Internet).
.
Yes, I understand that, but after
following the prompts for installing the
centos system in the vm and VMM itself
this is what resulted and I don't know
what it is supposed to look like. All I
could do was compare the working with
the non working.
lo: flags=73<UP,LOOPBACK,RUNNING> mtu
65536
inet 127.0.0.1 netmask
255.0.0.0
inet6 ::1 prefixlen 128
scopeid 0x10<host>
loop txqueuelen 0 (Local
Loopback)
RX packets 128 bytes 11136
(10.8 KiB)
RX errors 0 dropped 0
overruns 0 frame 0
TX packets 128 bytes 11136
(10.8 KiB)
TX errors 0 dropped 0
overruns 0 carrier 0 collisions 0
virbr0:
flags=4099<UP,BROADCAST,MULTICAST>
mtu 1500
inet 192.168.122.1 netmask
255.255.255.0 broadcast
192.168.122.255
ether 52:54:00:71:23:11
txqueuelen 0 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0
overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0
overruns 0 carrier 0 collisions 0
virbr0 (virtual bridge zero) is
created by libvirt and used to route
traffic INSIDE that machine between
itself and the virtual machines
it's hosting. Note that it has the
192.168.122.1 address (typical of a
VM host acting as a router for the
virtual machines running under it)
and _virtual_ machines running on that
host it will have addresses on
that 192.168.122 network applied to
their eth0 interfaces (assuming
they're configured to use DHCP to get
an address).
[bobg@localhost ~]$ ping -c 3 8.8.8.8
connect: Network is unreachable
I don't know what I might have done
differently on the seond VM install,
incidentally both are installed
usingthe same centos 7 iso if that is of
interest ...
Any suggestion of what to do next
will be appreciated,
Give an IP address to eth0 on the
machine that's not working and/or
leave it using DHCP and ensure you
have a DHCP server on the network
it's plugged into.
Your network appears a bit weird to
me. My LAN uses 192.168.1.0/24
with 192.168.1.1 on the LAN side of my
router (the WAN side of the router has
a routable public IP). The router also
has a DHCP server
on it. I prefer to use fixed IPs for
my non-mobile devices, so I have
the DHCP server restricted to only
offer addresses between 192.168.1.192
and 192.168.1.254, letting me use
192.168.1.2 through .191 for fixed
IPs.
My first VM host (vmhost-a) has a
fixed address of 192.168.1.10 on eth0
(on the LAN). My second VM host
(vmhost-b) has a fixed address of
192.168.1.15 on eth0 (also on the
LAN). Both of them have default
routes that specify 192.168.1.1 (the
IP address of my router on the
LAN).
When libvirtd starts on both vmhost-a
and vmhost-b, it creates a
virbr0 interface on each and gives it
an address of 192.168.122.1. The
thing to note here is that even though
both machines have the same
address on virbr0, that network is
only visible INSIDE the physical
machine. This means the 192.168.122
network on vmhost-a does not
conflict with the 192.168.122 network
on vmhost-b.
If I start a VM on vmhost-b and that
VM has its eth0 configured to use
DHCP, it will get an address from the
DHCP server running as part of
libvirtd on vmhost-b. It will get an
IP address of 192.168.122.x (we'll
use .10 for an example) and a default
gateway of 192.168.122.1.
Now, if that VM sends traffic out, it
will go through its simulated
eth0 (192.168.122.10) and libvirtd
will see it on its virbr0 at
192.168.122.1. libvirtd will then
route the traffic out its eth0
(192.168.1.15) and the router will
pick that up off its 192.168.1.1
interface and route it through to the
internet. Replies go back down
the same pipeline in reverse.
Remember, the router sees the traffic
as coming from vmhost-b, so replies go
back to it. vmhost-b reroutes
the reply traffic through its virbr0
back to the VM.
I hope my example clears it up a bit.
There's a lot to absorb there.
Yes, everything helps. My LAN address
scheme is about the same as yours. I
think I will try assigning a fixed
address to the second box, if that works
I'll do the same on the one that is
working ...
I'll report the result tomorrow'
Thank you,
Bob
----------------------------------------------------------------------
- Rick Stevens, Systems Engineer,
AllDigital ricks@xxxxxxxxxxxxxx -
- AIM/Skype: therps2 ICQ:
226437340 Yahoo: origrps2 -
- -
- I will go to my happy place. I
WOULD go to my happy place.... -
- if I knew where the
@$>&$@#* it is! -
----------------------------------------------------------------------
--
Bob Goodwin - Zuni, Virginia, USA
http://www.qrz.com/db/W2BOD
box10 FEDORA-23/64bit LINUX XFCE POP3
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