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Re: [1/2] CARP implementation. HA master's failover.

To: johnpol@xxxxxxxxxxx
Subject: Re: [1/2] CARP implementation. HA master's failover.
From: jamal <hadi@xxxxxxxxxx>
Date: 16 Jul 2004 09:04:24 -0400
Cc: netdev@xxxxxxxxxxx, netfilter-failover@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20040715235313.69897131@zanzibar.2ka.mipt.ru>
Organization: jamalopolis
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On Thu, 2004-07-15 at 15:53, Evgeniy Polyakov wrote:
> On 15 Jul 2004 13:24:45 -0400
> jamal <hadi@xxxxxxxxxx> wrote:

> > What is it that CARP does that couldnt be achieved by VRRP? 
> 
> I will answer a question by question, sorry.

;->

> Has vrrp some authentification mechanism?

They (at least used to) claim to be able to do so.

> Can it be used over IPv6? (CARP also can't but it is _very_ easy to
> add, I just don't have IPv6 network setup to test).

Theres effort to have it do v6.
http://www.ietf.org/internet-drafts/draft-ietf-vrrp-ipv6-spec-06.txt
I agree its lame to have it as an after thought it seems

> May someone use vrrp in private commercial enviroment without fear of
> being convicted?

That i dont know.

> > 
> > Can you explain a little more what you mean by "attching" to
> > master/slave?
> 
> Consider using some abstraction layer which makes some decisions based
> on knowledge of current HA state.

sure; make it an API/callback/event to/from the carp daemon to other
applications.

> It looks like we do not understand each other :)
> Here is the explanation of the ct_sync:
> http://cvs.netfilter.org/netfilter-ha/README?rev=1.2&content-type=text/vnd.viewcvs-markup
> 
> Harald Welte will have a talk about ct_sync at OLS.


Ok, good. Maybe if you too come to OLS we can settle this ;->
Looking at what HArald has, the infrastructure seems to be the correct
flavor. Seems something gets sent to user space via netlink and gets
delivered via keepalived.
I think the CARP loadbalancing feature is an improvement over what is
being suggested by Harald.
I have to say as well i am shocked that state is just being transfered
blindly - but i will deal with Harald when he shows up in Ottawa ;->

> > What do you mean realtime traffic?
> > Is it something that can be achieved by qos prioritization?
> 
> Yes it can. But who will control prioritization mechanism?
> Maybe userspace.
> But with such approach we need to create each time we need kernel access
> a kernel agent with it's own kernel<->user protocol, it's own connect
> to master/slave arbiter...
> With CARP just create one function in kernelspace and register it in
> CARP using provided mechanism.

bah.
Ok, now you are forcing me to draw diagrams.

I attached to avouid it being mangled.

> > In the end CISCO is going to be the loser in this of because 
> > something like CARP will take off and it cant talk to them. At the
> > moment though they do have the market so interoping with them is
> > valuable.
> 
> It is just marketing...
> The better software the more market it can eat. Theoretically...

I am afraid even if that sounds logical it doesnt work like that.
Too many stupid people. If it worked like that MS would be dead and
buried a few years ago.


> In theory practice and theory are the same, but in practice they are
> different. (c) Larry McVoy.

Agreed.

> Why use not good software and has even theoretical possibility to be 
> convicted when we have free successor( :) I said it? Nah... ).

Ok, keep spreading fear ;-> You are getting me worried now ;->

> I have great confidence that Theo de Raadt will not include non
> patent-free code in OpenBSD.

I hope he is a lawyer or has some good lawyer advising him;->

cheers,
jamal

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