[lvs-users] LVS on localhost

[Julian Anastasov]

 	Hello,

On Thu, 24 Mar 2011, Joseph Mack NA3T wrote:

> On Thu, 24 Mar 2011, Julian Anastasov wrote:
>
>>> The ipvsadm syntax I've tried:
>>>
>>> ipvsadm -A -t 127.0.0.1:9000 -s rr
>>> ipvsadm -a -t 127.0.0.1:9000 -r 127.0.0.1:9100 -m
>>> ipvsadm -a -t 127.0.0.1:9000 -r 127.0.0.1:9200 -m
>>
>> 	LocalNode is rewritten in 2.6.37. The above commands
>> should work with NFCT enabled or disabled:
>
> I didn't know about this. Sorry Tim, looks like I've been
> misleading you.
>
>> http://archive.linuxvirtualserver.org/html/lvs-devel/2010-10/msg00134.html
>
> thanks. Are there instructions on setting up LocalNode and
> using ipvsadm as a result of these changes?

 	The above example is a combination of local
client and local real server and requires NAT due to
difference in ports. LocalNode was known as a method
that installs NULL transmitter, i.e. delivers the
traffic for VIP to the local stack without any
address/port manipulations.

 	The user visible changes from these patches
are as follows (2.6.37+):

- http://archive.linuxvirtualserver.org/html/lvs-devel/2010-10/msg00133.html

 		This patch allows NAT/DR/TUN real servers
 	to fallback to local-RIP mode at any time. It can
 	happen if the real IP is added/removed from server
 	or even for complex setups with master and backup
 	where the backup is a real server in the master
 	and when backup takes control we must assume
 	local mode for the synced connections that have
 	BACKUP_IP as RIP. Note that every sync-ed connection
 	comes with its forwarding method.

 		Another addition is the ability to use
 	NAT method for local real server. Before now
 	it was only LocalNode possible. Now you can
 	translate to different address and port as the
 	above example for 127.0.0.1

 		Now when adding real server you can not
 	see type Local if the RIP is a local address.
 	The forwarding type remains as configured, so that it
 	can be synced. As result, DR and TUN can fallback
 	to the known LocalNode mode. OTOH, NAT has
 	the option to translate to different local IP
 	and port, i.e. it is not exactly the LocalNode
 	as we know it.

- http://archive.linuxvirtualserver.org/html/lvs-devel/2010-10/msg00134.html

 	Now local client can work with NF conntracks.


 	To summarize, the rules are as before: if we
do not want translation we can use DR, if we require
translation we should use NAT.

Regards

--
Julian Anastasov <ja at ssi.bg>