Load balancing across 4 web servers in same datacentre - advice please

[carl_townshend]

Hi All

Im looking for some advice please

The apps team have asked me about load balancing across some servers but im not that well up on it for applications

Basically we have 4 apache web servers with about 2000 clients connecting to them, they would like to load balance connections to all these servers, they all need the same DNS name etc.

what load balancing methods would I need for this, I believe they run on Linux

Would I need some sort of device, or can the servers run some software that can do this, how would it work? and how would load balancing be achieved here?

cheers

[sivaksiv]

Hi,

If there is no specific requirement you could just leave it to default LB method round robin.

You could also loadbalance based on stickyness - src ip, cookie, url ..

http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/ace_appliances/vA3_1_0/configuration/slb/guide/sticky.html

-

Siva

[carl_townshend]

what do you mean default LB method of Round robin ? what would that be and how would it work ?

[Jorge Bejarano]

Carl,

What you have mentioned sounds very straightforward then everything should go well.

The ACE is a load balancer which takes a load balancing decisions based on different matching methods like matching virtual address, url, source address, etc then once the load balance decision has been taken then the ACE will load balance the traffic based on the load balance method which you have configured (if you do not configure anything then it will use the default which is "round robin"), then it will send the traffic to the servers which it has available and finally the client should get the content.

If you want to get some details about the load balancing methods here you have them:

http://www.cisco.com/en/US/docs/app_ntwk_services/data_center_app_services/ace_appliances/vA3_1_0/configuration/slb/guide/overview.html#wp1000976

For ACE deployments the most common designs are the following.

Bridge Mode

One Arm Mode

Routed Mode

Here you have a link for Bridge Mode and a sample for that:

http://docwiki.cisco.com/wiki/Basic_Load_Balancing_Using_Bridged_Mode_on_the_Cisco_Application_Control_Engine_Configuration_Example

Here you have a link for One Arm Mode and a sample for that:

http://docwiki.cisco.com/wiki/Basic_Load_Balancing_Using_One_Arm_Mode_with_Source_NAT_on_the_Cisco_Application_Control_Engine_Configuration_Example

Here you have a link for Routed Mode and a sample for that:

http://docwiki.cisco.com/wiki/Basic_Load_Balancing_Using_Routed_Mode_on_the_Cisco_Application_Control_Engine_Configuration_Example

Then as you could see in all those links you may end up having a configuration like this:

interface vlan 40

  description "Default gateway of real servers"

  ip address 192.168.1.1 255.255.255.0

  service-policy input remote-access

  no shutdown

ip route 0.0.0.0 0.0.0.0 172.16.1.1

class-map match-all slb-vip

  2 match virtual-address 172.16.1.100 any

policy-map multi-match client-vips

  class slb-vip

    loadbalance vip inservice

    loadbalance policy slb

policy-map type loadbalance http first-match slb

  class class-default

    serverfarm web

serverfarm host web

  rserver lnx1

    inservice

  rserver lnx2

    inservice

  rserver lnx3

    inservice

rserver host lnx1

  ip address 192.168.1.11

  inservice

rserver host lnx2

  ip address 192.168.1.12

  inservice

rserver host lnx3

  ip address 192.168.1.13

  inservice

Please mark it if it answered you question then other users can use it as reference in the future.

Hope this helps!

Jorge

[Jorge Bejarano]

Carl,

Did everything go well?

Jorge

[Cesar Roque]

Hi Carl,

Do you have a Cisco Loadbalance like ACE or CSS? 

If not, your probably wants to contact your Cisco Account Manager or Cisco System Engineer and they can give you the options based on your needs.

---------------------
Cesar R
ANS Team