[lvs-users] LVS Direct Routing Virtualized

Ferenc Wagner wferi at niif.hu
Sat Sep 21 12:57:48 BST 2013


Andrew Lau <andrew at andrewklau.com> writes:

> I have my LVS DR routing setup on a KVM nodes, from a single node it works
> great.
>
> Client->VIP->router dnat->loadbalancer->real server->router
> snat->VIP->client
>
> However when I spread the load across multiple KVM nodes, the connections
> still hit the real server however nothing seems to be going out
>
> Client->VIP->router dnat->LVS (kvm node 1)->real server (kvm node 2)
>
> I can see the traffic hitting the real server through the access logs, and
> a tcpdump shows it's trying to send the response out. 10.0.3.152 being my
> virtual IP. But the client doesn't seem to get the traffic.

The client certainly gets the traffic, these seem like normal TCP
session startups to me, with both ends actively involved.

> 16:35:47.370392 IP 112-113-114-23.optusnet.com.au.41046 > 10.0.3.152.http: Flags [S], seq 4091323321, win 14600, options [mss 1400,sackOK,TS val 25401631 ecr 0,nop,wscale 7], length 0
> 16:35:47.370472 IP 10.0.3.152.http > 112-113-114-23.optusnet.com.au.41046: Flags [S.], seq 4086913213, ack 4091323322, win 14600, options [mss 1460,nop,nop,sackOK,nop,wscale 9], length 0
> 16:35:47.383519 IP 112-113-114-23.optusnet.com.au.41046 > 10.0.3.152.http: Flags [.], ack 1, win 115, length 0
> 16:35:47.394633 IP 112-113-114-23.optusnet.com.au.41046 > 10.0.3.152.http: Flags [P.], seq 1:372, ack 1, win 115, length 371
> 16:35:47.394653 IP 10.0.3.152.http > 112-113-114-23.optusnet.com.au.41046: Flags [.], ack 372, win 31, length 0
> 16:35:47.394846 IP 10.0.3.152.http > 112-113-114-23.optusnet.com.au.41046: Flags [P.], seq 1:377, ack 372, win 31, length 376
> 16:35:47.406866 IP 112-113-114-23.optusnet.com.au.41046 > 10.0.3.152.http: Flags [.], ack 377, win 123, length 0

> 16:35:47.412737 IP 112-113-114-23.optusnet.com.au.41047 > 10.0.3.152.http: Flags [S], seq 1141657121, win 14600, options [mss 1400,sackOK,TS val 25401671 ecr 0,nop,wscale 7], length 0
> 16:35:47.412760 IP 10.0.3.152.http > 112-113-114-23.optusnet.com.au.41047: Flags [S.], seq 954827421, ack 1141657122, win 14600, options [mss 1460,nop,nop,sackOK,nop,wscale 9], length 0
> 16:35:47.424931 IP 112-113-114-23.optusnet.com.au.41047 > 10.0.3.152.http: Flags [.], ack 1, win 115, length 0
> 16:35:47.435810 IP 112-113-114-23.optusnet.com.au.41047 > 10.0.3.152.http: Flags [P.], seq 1:376, ack 1, win 115, length 375
> 16:35:47.435822 IP 10.0.3.152.http > 112-113-114-23.optusnet.com.au.41047: Flags [.], ack 376, win 31, length 0
> 16:35:47.472455 IP 10.0.3.152.http > 112-113-114-23.optusnet.com.au.41047: Flags [P.], seq 1:471, ack 376, win 31, length 470
> 16:35:47.484230 IP 112-113-114-23.optusnet.com.au.41047 > 10.0.3.152.http: Flags [.], ack 471, win 123, length 0
> 16:35:47.594953 IP 112-113-114-23.optusnet.com.au.41047 > 10.0.3.152.http: Flags [P.], seq 376:659, ack 471, win 123, length 283
> 16:35:47.597063 IP 10.0.3.152.http > 112-113-114-23.optusnet.com.au.41047: Flags [P.], seq 471:1183, ack 659, win 33, length 712
> 16:35:47.610358 IP 112-113-114-23.optusnet.com.au.41047 > 10.0.3.152.http: Flags [.], ack 1183, win 134, length 0

> 16:35:47.416050 IP 112-113-114-23.optusnet.com.au.41048 > 10.0.3.152.http: Flags [S], seq 431016436, win 14600, options [mss 1400,sackOK,TS val 25401671 ecr 0,nop,wscale 7], length 0
> 16:35:47.416064 IP 10.0.3.152.http > 112-113-114-23.optusnet.com.au.41048: Flags [S.], seq 3260231345, ack 431016437, win 14600, options [mss 1460,nop,nop,sackOK,nop,wscale 9], length 0
> 16:35:47.440424 IP 112-113-114-23.optusnet.com.au.41048 > 10.0.3.152.http: Flags [.], ack 1, win 115, length 0
-- 
Regards,
Feri.



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