Re: mod_proxy_balancer: how to define failover (only)/hot standby

[Jim Jagielski <ji...@jaguNET.com>]

Mladen Turk wrote:
> 
> Jim Jagielski wrote:
> > Actually, dev@httpd.apache.org is best, since that is where
> > the development of this module is being done. I have changed
> > the email headers accordingly.
> > 
> > A sort of "warm standby" is something that I had planned to
> > work into the balancer code post 2.2.1.
> >
> 
> Like said earlier.
> 
> Hot standby already works with mod_proxy balancer.
> The 'hot standby' BalancerMember must be initially 'disabled'.
> Other members must have 'redirect' option set to the name of
> 'hot standby' member.
> 

As I understand it, this is ajp specific though, isn't
it (it's been awhile since I look at that section - iirc
it's tied into session support)

-- 
===========================================================================
   Jim Jagielski   [|]   jim@jaguNET.com   [|]   http://www.jaguNET.com/
	    "If you can dodge a wrench, you can dodge a ball."

Re: mod_proxy_balancer: how to define failover (only)/hot standby

[Mladen Turk <mt...@apache.org>]

Jim Jagielski wrote:
> 
>>
>> The only problem is that it's not documented ;)
>>
> 
> Hmm... I thought that this happened via the code
> in find_session_route() and relied on sticky sessions;
> but again iirc they can be via cookies as well.
> So one issue is that stickysession must be used, I think.
>

Right. Also if the sessions are not replicated it makes no
sense to have hot-standby, cause the user will have to
login again.

find_session_route will check for 'redirect' if all other nodes
are unusable (in error or stopped) and make a failover.

Regards,
Mladen.

Re: mod_proxy_balancer: how to define failover (only)/hot standby

[Jim Jagielski <ji...@jaguNET.com>]

On Jan 24, 2006, at 12:18 PM, Mladen Turk wrote:

> Jim Jagielski wrote:
>> Mladen Turk wrote:
>>> Jim Jagielski wrote:
>>>> Actually, dev@httpd.apache.org is best, since that is where
>>>> the development of this module is being done. I have changed
>>>> the email headers accordingly.
>>>>
>>>> A sort of "warm standby" is something that I had planned to
>>>> work into the balancer code post 2.2.1.
>>>>
>>> Like said earlier.
>>>
>>> Hot standby already works with mod_proxy balancer.
>>> The 'hot standby' BalancerMember must be initially 'disabled'.
>>> Other members must have 'redirect' option set to the name of
>>> 'hot standby' member.
>>>
>> As I understand it, this is ajp specific though, isn't
>> it (it's been awhile since I look at that section - iirc
>> it's tied into session support)
>
> No. It works with any protocol.
>
> <Proxy balancer://mycluster>
>   BalancerMember ajp://hotstandby status=disabled
>   BalancerMember ajp://node1 redirect=hotstandby
>   BalancerMember ajp://node2 redirect=hotstandby
>   ...
>   BalancerMember ajp://nodeN redirect=hotstandby
> </Proxy>
>
> The only problem is that it's not documented ;)
>

Hmm... I thought that this happened via the code
in find_session_route() and relied on sticky sessions;
but again iirc they can be via cookies as well.
So one issue is that stickysession must be used, I think.

Re: mod_proxy_balancer: how to define failover (only)/hot standby

[Mladen Turk <mt...@apache.org>]

Jim Jagielski wrote:
> Mladen Turk wrote:
>> Jim Jagielski wrote:
>>> Actually, dev@httpd.apache.org is best, since that is where
>>> the development of this module is being done. I have changed
>>> the email headers accordingly.
>>>
>>> A sort of "warm standby" is something that I had planned to
>>> work into the balancer code post 2.2.1.
>>>
>> Like said earlier.
>>
>> Hot standby already works with mod_proxy balancer.
>> The 'hot standby' BalancerMember must be initially 'disabled'.
>> Other members must have 'redirect' option set to the name of
>> 'hot standby' member.
>>
> 
> As I understand it, this is ajp specific though, isn't
> it (it's been awhile since I look at that section - iirc
> it's tied into session support)
> 

No. It works with any protocol.

<Proxy balancer://mycluster>
   BalancerMember ajp://hotstandby status=disabled
   BalancerMember ajp://node1 redirect=hotstandby
   BalancerMember ajp://node2 redirect=hotstandby
   ...
   BalancerMember ajp://nodeN redirect=hotstandby
</Proxy>

The only problem is that it's not documented ;)

Regards,
Mladen.