Red Hat LINUX VIRTUAL SERVER 4.7 - ADMINISTRATION Guida di Installazione Scaricare il pdf (Pagina 29)

So the real server's /etc/sysconfig/network-scripts/ifcfg-eth0 file could look similar to this:

DEVICE=eth0

ONBOOT=yes

BOOTPROTO=static

IPADDR=10.11.12.1

NETMASK=255.255.255.0

GATEWAY=10.11.12.10

Warning

If a real server has more than one network interface configured with a GAT EWAY= line, the first

one to come up will get the gateway. Therefore if both eth0 and eth1 are configured and eth1

is used for LVS, the real servers may not route requests properly.

It is best to turn off extraneous network interfaces by setting ONBOOT=no in their network scripts

within the /etc/sysconfig/network-scripts/ directory or by making sure the gateway is

correctly set in the interface which comes up first.

3.1.3. Enabling NAT Routing on the LVS Routers

In a simple NAT LVS configuration where each clustered service uses only one port, like HT T P on port

80, the administrator needs only to enable packet forwarding on the LVS routers for the requests to be

properly routed between the outside world and the real servers. See Section 2.5, “Turning on Packet

Forwarding” for instructions on turning on packet forwarding. However, more configuration is necessary

when the clustered services require more than one port to go to the same real server during a user

session. For information on creating multi-port services using firewall marks, see Section 3.4, “Multi-port

Services and LVS”.

Once forwarding is enabled on the LVS routers and the real servers are set up and have the clustered

services running, use the Piranha Configuration Tool to configure LVS as shown in Chapter 4,

Configuring the LVS Routers with Piranha Configuration Tool.

Warning

Do not configure the floating IP for eth0:1 or eth1:1 by manually editing network scripts or

using a network configuration tool. Instead, use the Piranha Configurat ion Tool as shown in

Section 4.4, “GLOBAL SETTINGS” and Section 4.6.1, “T he VIRTUAL SERVER Subsection”.

When finished, start the pulse service as shown in Section 4.8, “Starting LVS”. Once pulse is up and

running, the active LVS router will begin routing requests to the pool of real servers.

3.2. LVS via Direct Routing

As mentioned in Section 1.4.2, “Direct Routing”, direct routing allows real servers to process and route

packets directly to a requesting user rather than passing outgoing packets through the LVS router.

Direct routing requires that the real servers be physically connected to a network segment with the LVS

router and be able to process and direct outgoing packets as well.

Net work Layout

In a direct routing LVS setup, the LVS router needs to receive incoming requests and route them

to the proper real server for processing. T he real servers then need to directly route the

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Red Hat LINUX VIRTUAL SERVER 4.7 - ADMINISTRATION Guida di Installazione Pagina 29