LVSKB - User contributions [en]

AIX Servers in LVS/DR and LVS/TUN Clusters

2011-04-14T20:05:55Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

Background :
It is possible to disable arp on a real interface via noarp option.
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply.
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify,
address : 10.80.1.3 (dotted decimal)
netmask : 255.255.255.0 (match your real network)
interface name : vi1 (or what you want)
activate interface : yes
interface to attach: lo0 (the real one, select the loopback ti disable arp)

Not real smit screens, it's a braindump...

Think ODM should be updated for persistence after reboot.

It works like a charm in production environments (1 yr now)
That's it.

--[[User:Bmontarges|Baptiste Montarges]] 01:58, 11 April 2010 (CST)

== References ==

* IBM documentation on Virtual Ethernet Interface on AIX

[[Category:ARP Issue]]

AIX Servers in LVS/DR and LVS/TUN Clusters

2011-04-14T20:04:43Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

Background :
It is possible to disable arp on a real interface via noarp option.
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply.
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify,
address : 10.80.1.3 (dotted decimal)
netmask : 255.255.255.0 (match your real network)
interface name : vi1 (or what you want)
activate interface : yes
interface to attach: lo0 (the real one, select the loopback ti disable arp)

Not real smit screens, it's a braindump...
think ODM should be updated for persistence after reboot.
it works like a charm in production environments (1 yr now)
That's it.

--[[User:Bmontarges|Baptiste Montarges]] 01:58, 11 April 2010 (CST)

== References ==

* IBM documentation on Virtual Ethernet Interface on AIX

[[Category:ARP Issue]]

AIX Servers in LVS/DR and LVS/TUN Clusters

2011-04-14T20:03:27Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

Background :
It is possible to disable arp on a real interface via noarp option.
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply.
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify,
address : 10.80.1.3 (dotted decimal)
netmask : 255.255.255.0 (match your real network)
interface name : vi1 (or what you want)
activate interface : yes
interface to attach: lo0 (the real one, select the loopback ti disable arp)

Not real smit screens, it's a braindump...
think ODM should be updated for persistence after reboot.
it works like a charm in production environments (1 yr now)
That's it.

--[[User:Bmontarges|Baptiste Montarges]] 01:58, 11 April 2010 (CST)

== References ==

* IBM documentation on Virtual Ethernet Interface on AIX

[[Category:ARP Issue]]

AIX Servers in LVS/DR and LVS/TUN Clusters

2010-04-11T11:16:44Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

Background :
It is possible to disable arp on a real interface via noarp option.
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply.
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify,
address : VIP/32 (dotted decimal)
netmask : 255.255.255.255
interface name : vi1 (or what you want)
activate interface : yes
interface to attach: lo0 (real one, select the loopback, smitty failed to attach other interface, an etherchannel in my case)

I made this quickly yesterday so i didn't took any notes or screens, I wrote the section from head.
think ODM should be updated for persistence after reboot.
didn't restart the system yet. will confirm soon.
will also update the post with real smit screens and corresponding cmd lines.

That(s it.
Sorry for wiki style or bad english. I work on it too...

--[[User:Bmontarges|Baptiste Montarges]] 01:58, 11 April 2010 (CST)

== References ==

* IBM documentation on Virtual Ethernet Interface on AIX

[[Category:ARP Issue]]

AIX Servers in LVS/DR and LVS/TUN Clusters

2010-04-10T17:58:10Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

To know :
It is possible to disable arp on a real interface via noarp option on setup.
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply...
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify :
address : VIP/32 (dotted decimal)
netmask : 255.255.255.255
interface name : vi1 (or what you want)
activate interface : yes
real intarface to attach: lo0 (select the loopback, smitty failed to attach other interface, an etherchannel in my case)

I made this quickly yesterday so i didn't took any notes or screens, I wrote the section from head.
think ODM should be updated for persistence after reboot.
didn't restart the system yet. will confirm soon.
will also update the post with real smit screens and corresponding cmd lines.

That(s it.
Sorry for wiki style or bad english. I work on it too...

--[[User:Bmontarges|Baptiste Montarges]] 01:58, 11 April 2010 (CST)

== References ==

* IBM documentation on Virtual Ethernet Interface on AIX

[[Category:ARP Issue]]

AIX Servers in LVS/DR and LVS/TUN Clusters

2010-04-10T17:43:33Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

To know :
It is possible to disable arp on a real interface via noarp option on setup.
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply...
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify :
address : VIP/32 (dotted decimal)
netmask : 255.255.255.255
interface name : vi1 (or what you want)
activate interface : yes
real intarface to attach: lo0 (select the loopback, smitty failed to attach on a etherchannel int. in my case)

I made this quickly on the fast yesterday so i didn't get notes or screens. I wrote the section from head only.
think ODM should be updated for persistence after reboot.
didn't restart the system yet. will confirm soon.
will also update the post with real smit screens and corresponding cmd lines.

That(s it.
Sorry for wiki style or bad english. I work on it too...

--[[User:Bmontarges|Bmontarges]] 01:18, 11 April 2010 (CST)

== References ==

* IBM documentation on Virtual Ethernet Interface on AIX

[[Category:ARP Issue]]

AIX Servers in LVS/DR and LVS/TUN Clusters

2010-04-10T17:29:01Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

To know :
It is possible to disable arp on a real interface via noarp option on setup.
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply...
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify :
address : VIP/32 (dotted decimal)
netmask : 255.255.255.255
interface name : vi1 (or what you want)
activate interface : yes
real intarface to attach: lo (select the loopback, smitty failed to attach on a etherchannel int. in my case)

I made this quickly on the fast yesterday so i didn't get notes or screens. I wrote the section from head only.
think ODM should be updated for persistence after reboot.
didn't restart the system yet. will confirm soon.
will also update the post with real smit screens and corresponding cmd lines.

That(s it.
Sorry for wiki style or bad english. I work on it too...

--[[User:Bmontarges|Bmontarges]] 01:18, 11 April 2010 (CST)

== References ==

* IBM documentation on Virtual Ethernet Interface on AIX

[[Category:ARP Issue]]

AIX Servers in LVS/DR and LVS/TUN Clusters

2010-04-10T17:26:25Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

To know :
It is possible to disable arp on a real interface via noarp option on setup.
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply...
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify :
address : VIP/32 (dotted decimal)
netmask : 255.255.255.255
interface name : vi1 (or what you want)
activate interface : yes
real intarface to attach: lo (select the loopback, smitty failed to attach on a etherchannel int. in my case)

I made this quickly on the fast yesterday so i didn't get notes or screens. I wrote the section from head only.
think ODM should be updated for persistence after reboot.
didn't restart the system yet. will confirm soon.
will also update the post with real smit screens and corresponding cmd lines.

That(s it.
Sorry for wiki style or bad english. I work on it too...

--[[User:Bmontarges|Bmontarges]] 01:18, 11 April 2010 (CST)

AIX Servers in LVS/DR and LVS/TUN Clusters

2010-04-10T17:19:35Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

To know :
It is possible to disable arp on a real interface via noarp option on setup.

If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply...

The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify :
address : VIP/32 (dotted decimal)
netmask : 255.255.255.255
interface name : vi1 (or what you want)
activate interface : yes
real intarface to attach: lo (select the loopback, smitty failed to attach on a etherchannel int. in my case)

From smitty, ODM should be updated for persistence after reboot.
I didn't restart the system yet. I will confirm asap.
I will also add the corresponding cmd line

That(s it.
Sorry for wiki style and english. I work on it too...
--[[User:Bmontarges|Bmontarges]] 01:18, 11 April 2010 (CST)

AIX Servers in LVS/DR and LVS/TUN Clusters

2010-04-10T17:18:37Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

To know :
It is possible to disable arp on a real interface via noarp option on setup
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply...
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not only an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify :
address : VIP/32 (dotted decimal)
netmask : 255.255.255.255
interface name : vi1 (or what you want)
activate interface : yes
real intarface to attach: lo (select the loopback, smitty failed to attach on a etherchannel int. in my case)

From smitty, ODM should be updated for persistence after reboot.
I didn't restart the system yet. I will confirm asap.
I will also add the corresponding cmd line

That(s it.
Sorry for wiki style and english. I work on it too...
--[[User:Bmontarges|Bmontarges]] 01:18, 11 April 2010 (CST)

AIX Servers in LVS/DR and LVS/TUN Clusters

2010-04-10T17:16:07Z

Bmontarges: /* Disable ARP for VIP */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

To know :
It is possible to disable arp on a real interface via noarp option on setup
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply...
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface (not only an alias) that is not arp-able

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specify :
address : VIP/32 (dotted decimal)
netmask : 255.255.255.255
interface name : vi1 (or what you want)
activate interface : yes
real intarface to attach: lo (select the loopback, smitty failed to attach on a etherchannel int. in my case)

From smitty, ODM should be updated for persistence after reboot.
I didn't restart the system yet. I will confirm asap.
I will also add the corresponding cmd line

That(s it
Sorry for my english. I work on it too..

AIX Servers in LVS/DR and LVS/TUN Clusters

2010-04-10T17:06:31Z

Bmontarges: /* Introduction */

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested ok on AIX 6.1, sould works from AIX 5L

== Disable ARP for VIP ==

To know :
It is possible to disable arp on a real interface via noarp option on setup
If a real interface is set up with arp on, you cannot add a inet alias on it whitout arp reply...
The AIX "Virtual IP Address Interface" implementation allow you to add a virtual interface

In [[LVS/DR]] clusters, we can disable ARP for [[VIP]] on AIX as follows:
smitty inet
select "Add de Virtual IP Address Interface"
under setup screen, specifiy :
VIP/32
netmask
interface name : vi1 (or whay you want)
activate to : yes
real intarface to attach: lo (select the loopback, smitty failed to attach on a etherchannel int. in my case)

That(s it

From smitty, ODM should be updated for persistence after reboot.
I didn't restart the system yet. I will confirm asap.

ifconfig lo0:1 VIP/32 netmask 255.255.255.255 up
These two commands can be added just after configuring loopback command in the
/etc/rc.S/S??network, so that VIP can be brought up after system boots up.

AIX Servers in LVS/DR and LVS/TUN Clusters

2010-04-10T16:52:45Z

Bmontarges: New page: == Introduction == In the AIX operating systems, ip addresses configured on the loopback interface will not participate the ARP protocol. Tested on AIX 6.1 (production), sould works f...

== Introduction ==

In the AIX operating systems, ip addresses configured on the loopback interface will not participate the [[ARP]] protocol.
Tested on AIX 6.1 (production), sould works from AIX 5L

ARP Issues in LVS/DR and LVS/TUN Clusters

2010-04-10T16:47:01Z

Bmontarges: /* Solutions */

== Problems ==

In the [[LVS/DR]] and [[LVS/TUN]] clusters, we can see that the [[VIP]] address is shared by [[load balancer]] and all [[real server]]s. In order to make the [[LVS/DR]] and [[LVS/TUN]] clusters work, [[load balancer]] should broadcast the [[VIP]] address to accept incoming packets for virtual service, the [[real server]]s only use the [[VIP]] address to process the packets for [[VIP]] locally.

The ARP problem arises when real servers have one of their interfaces connected to the network that [[LVS/DR]] and [[LVS/TUN]] [[load balancer]] receives packets for [[VIP]]. For example, a [[LVS/DR]] or [[LVS/TUN]] cluster of the following topology needs to disable ARP for [[VIP]] address at real servers.

[[Image:Cluster-need-disable-arp-for-VIP-at-realservers.png|center]]

If we did not disable ARP for [[VIP]] address at real servers, there would be race condition in ARP response, the load balancer and the real servers may give ARP response for VIP simultaneously, then router might send requests for VIP to real servers directly instead of the load balancer. This would break the whole load balancing solution.

In a [[LVS/DR]] and [[LVS/TUN]] cluster of some special configuration illustrated in the following figure, real servers don't have any interfaces connected to the network that [[load balancer]] receives packets for [[VIP]], but have their router to transmit response packets, then there is no need to disable ARP for VIP at real servers, because there is no chances for real servers to receive ARP request for VIP.

[[Image:Cluster-not-need-to-disable-arp.png|center]]

Anyway, there is no hurt to disable ARP for VIP at real servers in any [[LVS/DR]] and [[LVS/TUN]] clusters.

== Solutions ==

=== Linux ===

There are many solutions to disable ARP for VIP in real servers running the Linux operating system.

* [[Using arptables to disable ARP]]
* [[Using arp_announce/arp_ignore to disable ARP]]
* [[Using the hidden interface to disable ARP]]
* [[Using redirect to disable ARP]]
* [[Using policy routing to disable ARP]]
* [[Using the noarp module to disable ARP]]

=== FreeBSD ===

[[LVS/DR]] and [[LVS/TUN]] clusters can work with FreeBSD [[real server]]s without any problems. See the article [[Disable ARP on FreeBSD]] for more information.

=== Solaris ===

[[LVS/DR]] and [[LVS/TUN]] clusters can also work with Solaris [[real server]]s without any problems. See the article [[Solaris Servers in LVS/DR and LVS/TUN Clusters]] for more information.

=== Windows ===

[[LVS/DR]] and [[LVS/TUN]] clusters can also work with Windows [[real server]]s without any problems. See the article [[Windows Servers in LVS/DR and LVS/TUN Clusters]] for more information.

=== AIX ===

[[LVS/DR]] and [[LVS/TUN]] clusters can also work with AIX [[real server]]s without any problems. See the article [[AIX Servers in LVS/DR and LVS/TUN Clusters]] for more information.

== References ==

* http://www.linuxvirtualserver.org/docs/arp.html

[[Category:LVS Handbook]]