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[lvs-users] ipvsadm stop-daemon command

 

 

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rohara at redhat

Oct 12, 2011, 2:12 PM

Post #1 of 3 (350 views)
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[lvs-users] ipvsadm stop-daemon command

What is the purpose of passing a state parameter (backup or master) to
the ipvsadm stop-daemon command? I fully understand why a state
parameter is desirable for the start-daemon command, but I can't think
of why stop-daemon would need this information. Is there more going on
that simply stopping the sync daemon?

There is no description of the stop-daemon command in the ipvsadm(8)
man page. Furthermore, it appears there is some inconsistencies in the
man page with respect to the required state parameter.

Thanks.

Ryan O'Hara
--
rohara [at] redhat


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horms at verge

Oct 12, 2011, 3:40 PM

Post #2 of 3 (332 views)
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Re: [lvs-users] ipvsadm stop-daemon command [In reply to]

Hi Ryan,

On Wed, Oct 12, 2011 at 04:12:12PM -0500, Ryan O'Hara wrote:
>
> What is the purpose of passing a state parameter (backup or master) to
> the ipvsadm stop-daemon command? I fully understand why a state
> parameter is desirable for the start-daemon command, but I can't think
> of why stop-daemon would need this information. Is there more going on
> that simply stopping the sync daemon?

It is possible to have both the master and backup daemon running at the
same time and the purpose of the state parameter to the stop-daemon command
is to allow them to be stopped individually.

> There is no description of the stop-daemon command in the ipvsadm(8)
> man page. Furthermore, it appears there is some inconsistencies in the
> man page with respect to the required state parameter.

It seems that the documentation predates the ability to have more than
one daemon running on a load balancer. Does the following text make
things clearer?

--start-daemon state

Start the connection synchronization daemon. The state may be
master or backup. The connection synchronization daemon is
implemented inside the Linux kernel. Daemons in one or both
states may be started on a load balancer.

A daemon running in the master state sends updates of connections
handled by the load balancer periodically using multicast. A
daemon in the backup state receives multicast message and creates
corresponding connection entries in kernel.

In a case where a primary load balancer running a synchronisation
daemon in the master state fails. If a backup load balancer that
has been running the synchronisation daemon in the backup state
takes over it will have state of almost all established connections
and these connections can continue to access the service.

Daemons may be stopped using --stop-daemon

--stop-daemon state

Stop the connection synchronization daemon. The state may be master
or backup and should match the state set when starting the daemon
that is to be stopped.

Daemons may be started using --start-daemon

_______________________________________________
Please read the documentation before posting - it's available at:
http://www.linuxvirtualserver.org/

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Send requests to lvs-users-request [at] LinuxVirtualServer
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rohara at redhat

Oct 13, 2011, 8:08 AM

Post #3 of 3 (326 views)
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Re: [lvs-users] ipvsadm stop-daemon command [In reply to]

On Thu, Oct 13, 2011 at 07:40:19AM +0900, Simon Horman wrote:
> Hi Ryan,
>
> On Wed, Oct 12, 2011 at 04:12:12PM -0500, Ryan O'Hara wrote:
> >
> > What is the purpose of passing a state parameter (backup or master) to
> > the ipvsadm stop-daemon command? I fully understand why a state
> > parameter is desirable for the start-daemon command, but I can't think
> > of why stop-daemon would need this information. Is there more going on
> > that simply stopping the sync daemon?
>
> It is possible to have both the master and backup daemon running at the
> same time and the purpose of the state parameter to the stop-daemon command
> is to allow them to be stopped individually.

That would explain it. I did not realize that a machine could run both
master and backup sync daemons.

> > There is no description of the stop-daemon command in the ipvsadm(8)
> > man page. Furthermore, it appears there is some inconsistencies in the
> > man page with respect to the required state parameter.
>
> It seems that the documentation predates the ability to have more than
> one daemon running on a load balancer. Does the following text make
> things clearer?

I understand. Thank you.

Ryan

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