[Gllug] Can't ssh from hypervisor to guest host using KVM

[Richard W.M. Jones]

On Fri, Apr 20, 2012 at 01:00:18PM +0100, JLMS wrote:
> Hello,
> 
> I am setting up a series of systems and while in my host at home I can
> happily do ssh from the hypervisor to the guests (CentOS 6.2 &
> Fedora16 respectively) I can't do the same in the host I am working
> with in the datacentre.
> 
> Whenever I try to ssh I get the following:
> 
> [root at ip-192-168-3-130 log]# ssh test at 192.168.111.199
> ssh: connect to host 192.168.111.199 port 22: No route to host
> [root at ip-192-168-3-130 log]#
> 
> while in my home server, I can do this with abandon:
> 
> [root at pinguino-centos jlms]# ssh test at 192.168.111.50
> test at 192.168.111.50's password:
> [root at pinguino-centos jlms]#
> 
> in both cases the guests can happily ssh to the hypervisor, and in
> both cases each host can ping each other, traceroute finds its way to
> each host both ways...
> 
> The major difference is that in the setup at home I disabled
> NetworkManger and gave the guest a static address, but I fail to see
> if that would impact in any way how this all hangs together.
> 
> This must be a common setup and I suppose most SAs would expect to be
> able to ssh as explained, what I am missing?

What you really need to do is tcpdump the traffic on the bridge device
(virbrX or similar), and compare it to a tcpdump of the traffic seen
by the guest.

Also have a look at the routing table in the host, which should have a
route to the bridge:

 $ netstat -rn
 [...]
 192.168.111.0   0.0.0.0    255.255.255.0   U     0 0     0 virbr0

>From the error, it sounds like this route is missing.

Finally, you are actually using the right IP address for the guest?

Rich.

-- 
Richard Jones
Red Hat
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