[Linux-cluster] Two node NFS cluster serving multiple networks

Thu Mar 13 20:39:25 UTC 2008

Google "linux policy based routing".

In your example you just need to setup different gateways for both
interfaces. For example:
ip route add default via 69.2.237.57 dev eth0 tab 1
ip route add default via 192.168.1.1 dev eth1 tab 2

On Thu, Mar 13, 2008 at 9:23 AM, isplist at logicore.net
<isplist at logicore.net> wrote:
> Is there a good document somewhere which explains in not too great technical
> terms how to use multiple nics on a system. I've been running bonded nics for
> many years but getting a machine to use two (or more networks) is still a
> mystery to me.
>
> For example, I have a VoIP machine which has two nics which I have problems
> with because I don't understand the above yet.
>
> This machine has a nic allows incoming VoIP/ZIP connections to it's public IP
> address on a T1. The router blocks everything but that traffic.
>
> Then it has a second nic which has a private IP on it to allow for management
> of the machine. Yet recently, it lost it's DNS, it can't seem to get access to
> DNS on it's own. I can force it to use DNS by typing ping commands a couple of
> times but it cannot do it on it's own to get it's updates for example.
>
> Basically, I need the machine to see it's public gateway at xx.x.237.59 to
> route it's VoIP/SIP traffic but I also need it to see it's private gateway at
> 192.168.1.0 so that it can use DNS and other internal services properly.
>
> route -n
> Kernel IP routing table
> Destination   Gateway      Genmask            Flags Metric Ref    Use Iface
> xx.x.237.56   0.0.0.0        255.255.255.248 U     0      0        0 eth0
> 192.168.1.0  0.0.0.0        255.255.255.0    U     0      0        0 eth1
> 169.254.0.0  0.0.0.0        255.255.0.0        U     0      0        0 eth1
> 0.0.0.0         69.2.237.57   0.0.0.0             UG    0      0        0 eth0
>
> ifconfig
> eth0      Link encap:Ethernet  HWaddr 00:90:27:DC:4B:E6
>          inet addr:xx.x.237.59  Bcast:69.2.237.63  Mask:255.255.255.248
>          inet6 addr: fe80::290:27ff:fedc:4be6/64 Scope:Link
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          RX packets:33910280 errors:16 dropped:0 overruns:0 frame:16
>          TX packets:45988648 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:24746 txqueuelen:1000
>          RX bytes:681966199 (650.3 MiB)  TX bytes:1657358619 (1.5 GiB)
>
> eth1      Link encap:Ethernet  HWaddr 00:13:20:55:D7:CE
>          inet addr:192.168.1.102  Bcast:192.168.1.255  Mask:255.255.255.0
>          inet6 addr: fe80::213:20ff:fe55:d7ce/64 Scope:Link
>          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>          RX packets:87417784 errors:0 dropped:0 overruns:0 frame:0
>          TX packets:70881957 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:1000
>          RX bytes:4171601084 (3.8 GiB)  TX bytes:1547562481 (1.4 GiB)
>
> lo        Link encap:Local Loopback
>          inet addr:127.0.0.1  Mask:255.0.0.0
>          inet6 addr: ::1/128 Scope:Host
>          UP LOOPBACK RUNNING  MTU:16436  Metric:1
>          RX packets:6501004 errors:0 dropped:0 overruns:0 frame:0
>          TX packets:6501004 errors:0 dropped:0 overruns:0 carrier:0
>          collisions:0 txqueuelen:0
>          RX bytes:897257336 (855.6 MiB)  TX bytes:897257336 (855.6 MiB)
>
>
> Mike
>
>
>
>
> On Wed, 12 Mar 2008 10:39:50 -0700, Alex Kompel wrote:
> > You will still need some way to tell the system through which
> >
> > interface you want to route outgoing packets for each target.
> > You can achieve the same with greater ease by splitting the network in
> > 2 subnets and assigning each to a single interface.
> > It all depends on the problem you are trying to solve. If you want
> > redundancy - use active-passive bonding, you want throughput - use
> > active-active bonding (if your switch supports link aggregation), if
> > you want security and isolation - use separate subnets.
> >
> > -Alex
> >
> > 2008/3/12 Brian Kroth <bpkroth at wisc.edu>:
> >> This is a hypothetical, but what if you have two interfaces on the same
> >> network and want to force one service IP to one interface and the other
> >> to a different interface?  I think what everyone is wondering is how
> >> much control one has over the service IP placement.
> >>
> >> Thanks,
> >> Brian
> >>
> >> Finnur Örn Guðmundsson - TM Software <fog at t.is> 2008-03-12 14:36:
> >>
> >>
> >>> Hi,
> >>>
> >>> I see no reason why you could not have 3 diffrent interfaces, each
> >>> connected to the networks you are trying to serve the NFS requests
> >>> to/from. RG Manager will add the floating interfaces to the "correct"
> >>> interface, that is, if your floating ip is 1.2.3.4 and you have a
> >>> interface with the IP address 1.2.3.3 he will add the IP to that
> >>> interface.
> >>>
> >>>
> >>> Bgrds,
> >>> Finnur
> >>>
> >>> -----Original Message-----
> >>> From: linux-cluster-bounces at redhat.com [mailto:linux-cluster-
> >>> bounces at redhat.com] On Behalf Of gordan at bobich.net
> >>> Sent: 12. mars 2008 14:10
> >>> To: linux clustering
> >>> Subject: Re: [Linux-cluster] Two node NFS cluster serving multiple
> >>> networks
> >>>
> >>> Sounds very similar to what I'm trying to achieve (see the other thread
> >>> about binding failover resources to interfaces). I've not seen a
> >>> response
> >>> yet, so I'm most curious to see if you'll get any.
> >>>
> >>> Gordan
> >>>
> >>> On Wed, 12 Mar 2008, Randy Brown wrote:
> >>>
> >>>> I am using a two node cluster with Centos 5 with up to date patches.
> >>>> We have
> >>>> three different networks to which I would like to serve nfs mounts
> >>>> from this
> >>>> cluster.  Can this even be done?  I have interfaces available for each
> >>>> network in each node?
> >>>>
> >>> --
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> >>>
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