[lvs-users] ldirectord question
IloL at bankservafrica.com
Fri Jun 20 09:02:16 BST 2014
Thanks for the feedback,
Once we have scheduled new connections to the new real server and we have this existing connection using quiescence ,
Why can't we move that existing connection to another real server ?
I know firewalls can move existing connections and TCP states between failover pairs
From: lvs-users-bounces at linuxvirtualserver.org [mailto:lvs-users-bounces at linuxvirtualserver.org] On Behalf Of Simon Horman
Sent: Friday, June 20, 2014 3:07 AM
To: Aaron West
Cc: LinuxVirtualServer.org users mailing list.
Subject: Re: [lvs-users] ldirectord question
On Thu, Jun 19, 2014 at 06:20:02PM +0100, Aaron West wrote:
> Hi Ilo,
> To my knowledge a real server failing a health check done by an agent
> such as ldirectord/keepalived is pulled from the LVS table.
> This will break any established connections to this server. A new
> connection should then start on a remaining live server on the next
> click/refresh for something like a web application or next connection
> retry for something else.
It is possible, though not necessarily desirable, to avoid breaking existing connections by using quiescence. On the LVS side this is implemented by setting a server weight to zero, which allows existing connections to continue but prevents new connections from being "scheduled".
This is exposed in ldirectord as a quiescence setting by which it sets the weight of a real-server to zero rather than removing it in the case where its health check fails.
I am not familiar with keepalived but I suspect it has a similar feature.
> How this affects your app/users depends on your application design,
> mostly HTTP sessions would be fine while things like RDP/SSH/HTTPS
> would require you to reconnect/re-authenticate.
> Aaron West
> On 19 June 2014 16:42, Ilo Lorusso <IloL at bankservafrica.com> wrote:
> > Hi ,
> > I have a general question of how ldirectord works, I have setup my
> > virtual service and real servers
> > I have an active connection and traffic is flowing through to the
> > real server perfectly as shown below
> > I want to know is it possible to move an established connection
> > between the real servers without resetting or reestablishing the TCP connection ?
> > [root at lbmaster ~]# ipvsadm -Ln
> > IP Virtual Server version 1.2.1 (size=32768) Prot LocalAddress:Port
> > Scheduler Flags
> > -> RemoteAddress:Port Forward Weight ActiveConn InActConn
> > TCP 172.16.162.190:40054 wlc persistent 300
> > -> 172.16.162.199:40054 Masq 100 1 0
> > -> 172.16.162.200:40054 Masq 99 0 0
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or go to http://lists.graemef.net/mailman/listinfo/lvs-users
BankservAfrica is a BBBEE level 4 procurement contributor
This e-mail and its attachments, if any, are subject to BankservAfrica's e-mail disclaimer which is available on
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