Re: Multiple Proxies

[Guillaume Bourque]

Jan-Frode Myklebust a écrit :

On 2009-03-17, John Lauro  wrote:
  

You need to explain a little more, as I am not understating something.
Perhaps what you mean by VIP?



Virtual IP address. With heartbeat, one normally has one staticly defined
ip-address on the frontend interface on each server, and then additionally
one or more VIPs that can be moved between servers.

Server1 has static IP on eth0 and the VIP eth0:1
Server2 has static IP on eth0

If server1 fails, server2 takes over eth0:1.

  

If they share the same single VIP at the same time, then why would you use
round-robin DNS?  Round-robin is for multiple IP addresses...?



I use one VIP on each server, and use round robin DNS to distribute the
load over all the servers. If one of the servers go down / is taken down
for maintenance, I move its VIP to the other server.

  

Also, if you do a virtual IP like Microsoft Windows does for their multicast
load balancing, that is just plain nasty to your network infrastructure if
you have more than those servers on the same subnet and IMHO really doesn't
scale well...

That's true that Micro$oft use a lot of bandwith, but keepalived and 
haertbeat dont !  They generated a low traffic impact.  You can also 
specify the frequence on multicast which can be 1 / sec if you want.


Also if your worry about multicast you can specify on which nic the 
multicast will happen.What we usually do is connect a cross cable 
between server1 and server2 on a seperate nic and you we tell keepalived 
to use that seperate nic for cluster traffic, ( The traffic that will 
tell what server are up, not the actual web traffic)


Cheer.


That doesn't sound like what we do, no.

  

If you meant a different VIP instead of one bound to each server, I could
understand that.  However, 50% of the clients will feel the hit when first
connecting if a server is down.



Not when the VIP moves over to the server that's still up, which is what
heartbeat does for me.


  -jf


  



--
Guillaume Bourque, B.Sc.,
consultant, infrastructures technologiques libres !
514 576-7638

Re: Multiple Proxies

[Jan-Frode Myklebust]

On 2009-03-17, John Lauro  wrote:
> You need to explain a little more, as I am not understating something.
> Perhaps what you mean by VIP?

Virtual IP address. With heartbeat, one normally has one staticly defined
ip-address on the frontend interface on each server, and then additionally
one or more VIPs that can be moved between servers.

Server1 has static IP on eth0 and the VIP eth0:1
Server2 has static IP on eth0

If server1 fails, server2 takes over eth0:1.

>
> If they share the same single VIP at the same time, then why would you use
> round-robin DNS?  Round-robin is for multiple IP addresses...?

I use one VIP on each server, and use round robin DNS to distribute the
load over all the servers. If one of the servers go down / is taken down
for maintenance, I move its VIP to the other server.

>
> Also, if you do a virtual IP like Microsoft Windows does for their multicast
> load balancing, that is just plain nasty to your network infrastructure if
> you have more than those servers on the same subnet and IMHO really doesn't
> scale well...

That doesn't sound like what we do, no.

>
> If you meant a different VIP instead of one bound to each server, I could
> understand that.  However, 50% of the clients will feel the hit when first
> connecting if a server is down.

Not when the VIP moves over to the server that's still up, which is what
heartbeat does for me.


  -jf

RE: Multiple Proxies

[John Lauro]

You need to explain a little more, as I am not understating something.
Perhaps what you mean by VIP?

If they share the same single VIP at the same time, then why would you use
round-robin DNS?  Round-robin is for multiple IP addresses...?

Also, if you do a virtual IP like Microsoft Windows does for their multicast
load balancing, that is just plain nasty to your network infrastructure if
you have more than those servers on the same subnet and IMHO really doesn't
scale well...


If you meant a different VIP instead of one bound to each server, I could
understand that.  However, 50% of the clients will feel the hit when first
connecting if a server is down.



> -Original Message-
> From: news [mailto:n...@ger.gmane.org] On Behalf Of Jan-Frode Myklebust
> Sent: Tuesday, March 17, 2009 2:53 PM
> To: haproxy@formilux.org
> Subject: Re: Multiple Proxies
> 
> I would use one VIP bound to each server, and use round-robin DNS to
> distribute the load over them. And with cookies for pinning it
> shouldn't
> matter to the clients which VIP it reaches.
> 
> 
>-jf

Re: Multiple Proxies

[Jan-Frode Myklebust]

On 2009-03-17, Joseph Hardeman  wrote:
>
> John is right, the way to do this is to use either heartbeat or 
> keepalive and fail over a VIP to a secondary machine in case the first 
> has issues.  Make sure your haproxy files are identical and then test 
> the failover. 

I would use one VIP bound to each server, and use round-robin DNS to
distribute the load over them. And with cookies for pinning it shouldn't
matter to the clients which VIP it reaches.


   -jf

Re: Multiple Proxies

[Joseph Hardeman]

Scott,

John is right, the way to do this is to use either heartbeat or 
keepalive and fail over a VIP to a secondary machine in case the first 
has issues.  Make sure your haproxy files are identical and then test 
the failover. 

We use heartbeat for one of our clients and so far any time I have had 
to either fail it over or it failed over on its own, we only lost 1 - 2 
packets.


If your web servers require the visitors to be pinned to that system for 
application reasons, make sure you have cookies setup in haproxy so that 
when it fails over, the secondary haproxy server knows where to send the 
visitor.


Joe

John Lauro wrote:


Not built into Haproxy, but you can use heartbeat or keepalived along 
with haproxy for IP takeover on a pair of physical boxes (or VMs).


 


*From:* Scott Pinhorne [mailto:scott.pinho...@voxit.co.uk]
*Sent:* Tuesday, March 17, 2009 10:52 AM
*To:* haproxy@formilux.org
*Subject:* Multiple Proxies

 


Hi All

 

I am using haproxy to load balance/failover on a  couple of my dev 
HTTP servers and it works really well.


I would like to introduce hardware redundancy for the haproxy server, 
is this possible with the software?


 


Best Regards

Scott Pinhorne

 


Tel: 0845 862 0371

 


cid:image001.jpg@01C93684.B3F9B800

 


http://www.voxit.co.uk

 


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RE: Multiple Proxies

[John Lauro]

Not built into Haproxy, but you can use heartbeat or keepalived along with
haproxy for IP takeover on a pair of physical boxes (or VMs).

 

From: Scott Pinhorne [mailto:scott.pinho...@voxit.co.uk] 
Sent: Tuesday, March 17, 2009 10:52 AM
To: haproxy@formilux.org
Subject: Multiple Proxies

 

Hi All

 

I am using haproxy to load balance/failover on a  couple of my dev HTTP
servers and it works really well.

I would like to introduce hardware redundancy for the haproxy server, is
this possible with the software?

 

Best Regards

Scott Pinhorne

 

Tel: 0845 862 0371

 

cid:image001.jpg@01C93684.B3F9B800

 

http://www.voxit.co.uk

 

P Please consider the environment before printing this email.

PRIVACY AND CONFIDENTIALITY NOTICE 

The information in this email is for the named addressee only. As this email
may contain confidential or privileged information if you are not, or
suspect that you are not, the named addressee other person responsible for
delivering the message to the named addressee, please contact us
immediately. Please note that we cannot guarantee that this message has not
been intercepted and amended. The views of the author may not necessarily
reflect those of VoxIT Ltd.

 

VIRUS NOTICE 

The contents of any attachment may contain software viruses, which could
damage your own computer. While VoxIT Ltd has taken reasonable precautions
to minimise the risk of software viruses, it cannot accept liability for any
damage, which you may suffer as a result of such viruses. We recommend that
you carry out your own virus checks before opening any attachment.

 


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