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Re: [lvs-users] lvs not routing to real

To: "LinuxVirtualServer.org users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] lvs not routing to real
From: Mike Ruskai <thannyd@xxxxxxxxxxxxx>
Date: Tue, 26 Sep 2017 10:11:15 -0400
What do you mean the director replies? You have that resource configured 
with direct routing, which means the LVS director has nothing to do with 
replying to the client. The real server is responsible for replying 
directly back to the client.

Do you have routing set up correctly?  You're using an internal IP 
address to refer to the real server, while the virtual IP is an external 
one.  Why doesn't the tcpdump info show the virtual IP? Should you be 
using NAT instead of DR?

On 9/23/2017 20:20, Srinivas Boga wrote:
> my bad, the reset on real server is happening as the part of the tcp check
> and not from load balancer
>
> So the lvs director replies with rst,ack as a reply to syn packet
>
> -srini
>
> On Sat, Sep 23, 2017 at 9:46 AM, Srinivas Boga <bseenu@xxxxxxxxx> wrote:
>
>> In AWS, I am trying to get the keepalived/ipvs working and see that the
>> load balancer/director does not forward the requests to my real server
>>
>>
>>      ubuntu@ip-172-31-6-2:~$ cat /etc/keepalived/keepalived.conf
>>      global_defs {
>>          notification_email {
>>              test@xxxxxxxx
>>          }
>>      }
>>
>>      virtual_server 13.57.18.235 1935 {
>>          delay_loop 30
>>          lb_algo rr
>>          lb_kind DR
>>          persistence_timeout 50
>>          protocol TCP
>>          real_server 172.31.12.15 1935 {
>>              TCP_CHECK {
>>                  connect_port 1935
>>                  connect_timeout 3
>>               }
>>          }
>>      }
>>
>>      vrrp_instance v1 {
>>          state MASTER
>>          interface eth0
>>          lvs_sync_daemon_interface eth0
>>          virtual_router_id 51
>>          priority 150
>>          advert_int 1
>>          virtual_ipaddress {
>>                 13.57.18.235
>>          }
>>      }
>>
>>      ubuntu@ip-172-31-6-2:~$ sudo ipvsadm -L -n
>>      IP Virtual Server version 1.2.1 (size=4096)
>>      Prot LocalAddress:Port Scheduler Flags
>>        -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
>>      TCP  13.57.18.235:1935 rr persistent 50
>>        -> 172.31.12.15:1935            Route   1      0          0
>>
>>      loopback on real
>>
>>      ubuntu@ip-172-31-12-15:~$ ifconfig lo:0
>>      lo:0      Link encap:Local Loopback
>>                inet addr:13.57.18.235  Mask:255.0.0.0
>>                UP LOOPBACK RUNNING  MTU:65536  Metric:1
>>
>> When i run tcpdump on both the loadbalancer and real see that tcp reset
>> happens on the loadbalancer after sync and reset happens after the
>> handshake on the real
>>
>> tcpdump on loadbalancer
>>
>>      03:50:35.405489 IP (tos 0x0, ttl 51, id 59005, offset 0, flags [DF],
>> proto TCP (6), length 64)
>>          c-98-207-84-68.hsd1.ca.comcast.net.51279 >
>> ip-172-31-6-2.us-west-1.compute.internal.1935: Flags [S], cksum 0x4e32
>> (correct), seq 2162214371 <(216)%20221-4371>, win 65535, options [mss
>> 1460,nop,wscale 5,nop,nop,TS val 373641902 ecr 0,sackOK,eol], length 0
>>      E..@.}@.3...b.TD.....O..............N2.............
>>      .ER.........
>>      03:50:35.405531 IP (tos 0x0, ttl 64, id 46103, offset 0, flags [DF],
>> proto TCP (6), length 40)
>>          ip-172-31-6-2.us-west-1.compute.internal.1935 >
>> c-98-207-84-68.hsd1.ca.comcast.net.51279: Flags [R.], cksum 0x2ff8
>> (correct), seq 0, ack 1, win 0, length 0
>>      E..(..@.@.......b.TD...O........P.../...
>>
>> tcpdump on real
>>
>>       ip-172-31-6-2.us-west-1.compute.internal.44230 >
>> ip-172-31-12-15.us-west-1.compute.internal.1935: Flags [S], cksum 0x9ef2
>> (correct), seq 2759878464, win 26883, options [mss 8961,sackOK,TS val
>> 2324983234 ecr 0,nop,wscale 7], length 0
>>      E..<.v@.@.?...............g@......i.......#....
>>      ..m.........
>>      03:51:52.362958 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto
>> TCP (6), length 60)
>>          ip-172-31-12-15.us-west-1.compute.internal.1935 >
>> ip-172-31-6-2.us-west-1.compute.internal.44230: Flags [S.], cksum 0x6a7e
>> (incorrect -> 0x7528), seq 527723804, ack 2759878465, win 26847, options
>> [mss 8961,sackOK,TS val 156996593 ecr 2324983234,nop,wscale 7], length 0
>>      E..<..@.@..l.............tm...gA..h.j~....#....
>>      [....m.....
>>        ip-172-31-6-2.us-west-1.compute.internal.44230 >
>> ip-172-31-12-15.us-west-1.compute.internal.1935: Flags [.], cksum 0x294e
>> (correct), seq 1, ack 1, win 211, options [nop,nop,TS val 2324983234 ecr
>> 156996593], length 0
>>      E..4.w@.@.?...............gA.tm.....)N.....
>>      ..m. [..
>>      03:51:52.363391 IP (tos 0x0, ttl 64, id 36984, offset 0, flags [DF],
>> proto TCP (6), length 52)
>>          ip-172-31-6-2.us-west-1.compute.internal.44230 >
>> ip-172-31-12-15.us-west-1.compute.internal.1935: Flags [R.], cksum 0x294a
>> (correct), seq 1, ack 1, win 211, options [nop,nop,TS val 2324983234 ecr
>> 156996593], length 0
>>      E..4.x@.@.?...............gA.tm.....)J.....
>>      ..m. [..
>>
>> Let me know if i am missing anything here
>>
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