[lvs-users] If deleting real server, how the persistent option works

Simon Horman horms at verge.net.au
Thu Jun 2 00:51:10 BST 2011


On Wed, Jun 01, 2011 at 02:20:32PM +0800, JR Wang wrote:
> Dear all:
> 
> I take the persistent option and would deleting the real server during the
> served duration.
> 
> If the same client take the connection again, where the connection would be
> directed and what real server would take the service?
> 
> Because I wanna use LVS to simulate a dynamic situation which could
> dynamically delete and add the server to be served ?

The simple answer is that new connections will go to
a different real-server.

A more detailed description follows:

If you delete a service then internally it is marked as
being unavailable.

When a new connection is scheduled using persistence the first step is to
see if there is an existing valid persistence template. In the case where
the destination of a template is unavailable, the template is made invalid
at the time of such a lookup. And the template is not used to schedule the
connection or any subsequent connections.

As there is no valid connection template, normal scheduling of the
connection will occur using the configured scheduling algorithm. And a new
persistence template will be created created and used for subsequent
connections.




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