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dvbell
30-Oct-2012, 19:22
We have 2 internal web servers that are being load balanced round robin by an ACE. The ACE is going away and will not be replaced with an appliance.

My boss would like to have the 2 internal web servers receive the http requests and decide between them which will actually handle the request in a round robin configuration without adding an additional server or appliance into the equation. This would eliminate a single point of failure, the appliance, and if one of the servers goes down the other will continue to service the http requests.

I'm told that Windows does NLB with a few clicks between 2 servers and doesn't require using a third device like the ACE.

Is this possible to configure on Linux? Is there software to make this happen or can it be done with only the OS? We are using SUSE SLES 11 SP2. Thanks. :confused:

malcolmlewis
30-Oct-2012, 20:16
On Tue, 30 Oct 2012 18:24:03 +0000, dvbell wrote:

> We have 2 internal web servers that are being load balanced round robin
> by an ACE. The ACE is going away and will not be replaced with an
> appliance.
>
> My boss would like to have the 2 internal web servers receive the http
> requests and decide between them which will actually handle the request
> in a round robin configuration without adding an additional server or
> appliance into the equation. This would eliminate a single point of
> failure, the appliance, and if one of the servers goes down the other
> will continue to service the http requests.
>
> I'm told that Windows does NLB with a few clicks between 2 servers and
> doesn't require using a third device like the ACE.
>
> Is this possible to configure on Linux? Is there software to make this
> happen or can it be done with only the OS? We are using SUSE SLES 11
> SP2. Thanks. :confused:
Hi
Something like multipath;
http://support.novell.com/techcenter/sdb/en/2005/04/sles_multipathing.html

or perhaps;
http://www.novell.com/communities/node/12621/load-balancing-smt-servers-
sles11-sp1-hae-cluster


--
Cheers Malcolm °¿° (Linux Counter #276890)
openSUSE 12.2 (x86_64) Kernel 3.4.11-2.16-desktop
up 1 day 20:01, 3 users, load average: 0.08, 0.09, 0.13
CPU Intel i5 CPU M520@2.40GHz | Intel Arrandale GPU

dvbell
31-Oct-2012, 14:30
Something like multipath;
http://support.novell.com/techcenter/sdb/en/2005/04/sles_multipathing.html

I tracked down the SLES 11 SP2 doc for your link above, and it mentions multipathing, but I could not find anything on round robin load balancing.

or perhaps;
http://www.novell.com/communities/node/12621/load-balancing-smt-servers-
sles11-sp1-hae-cluster

The link above requires using a third server to do the load balancing and that is outside the parameters I gave. Sorry, but thanks.

cjcox
31-Oct-2012, 15:21
On 10/30/2012 01:24 PM, dvbell wrote:
>
> We have 2 internal web servers that are being load balanced round robin
> by an ACE. The ACE is going away and will not be replaced with an
> appliance.
>
> My boss would like to have the 2 internal web servers receive the http
> requests and decide between them which will actually handle the request
> in a round robin configuration without adding an additional server or
> appliance into the equation. This would eliminate a single point of
> failure, the appliance, and if one of the servers goes down the other
> will continue to service the http requests.
>
> I'm told that Windows does NLB with a few clicks between 2 servers and
> doesn't require using a third device like the ACE.
>
> Is this possible to configure on Linux? Is there software to make this
> happen or can it be done with only the OS? We are using SUSE SLES 11
> SP2. Thanks. :confused:
>
>

IMHO, whoever said Windows does safe LB without anything else doesn't understand
much.

If we can throw some state stuff out the window.. then fine... just LB by
rotating via multiple DNS A records. That's the easiest way.

If want things like session stickiness and SSL, etc... you really need to
consider a LB device (or two for at least failover redundancy).

Bob-O-Rama
05-Nov-2012, 04:26
My solution for this is pretty simple:

Use keepalived / VRRPd / whatever to create TWO virtual IP's spamming bother servers. Then use round robin DNS to present the two to clients. Here is an example with fake IPs:

Server A:

Real IP: 10.10.10.10
Virt IP 1: 10.10.10.1 <-- Master
Virt IP 2: 10.10.10.2 <-- Slave

Real IP: 10.10.10.20
Virt IP 1: 10.10.10.1 <-- Slave
Virt IP 2: 10.10.10.2 <-- Master

NDS:

www.foo.com 10.10.10.1
www.foo.com 10.10.10.2

A client will get either .1 or .2 which will go to the server which is the Master for that IP. If either server fails, the other server will be the Master for BOTH .1 and .2 hence handling failover. This will handle most use cases.

-- Bob

jmozdzen
05-Nov-2012, 11:35
Hi dvbell,

>> http://www.novell.com/communities/no...g-smt-servers- (http://www.suse.com/company/novell_redirect.html?url=http://www.novell.com/communities/node/12621/load-balancing-smt-servers-)sles11-sp1-hae-cluster
> The link above requires using a third server to do the load balancing and that is outside the parameters I gave. Sorry, but thanks.

while I have not read the linked documentation, I know from experience that you don't need a third machine to run load-balanced web servers with HAE cluster.

Regards,
Jens