Re: [dnsdist] Backend Questions

2022-11-02 Thread Klaus Darilion via dnsdist 


> > Shouldn't newServer(...healthCheckMode='UP') also work? In my case it
> does not work.
> > I have set healthCheckMode='UP' but:
> > showServers show status as "up" whereas after setUp() the status is "UP".
> And it still does helathchecks and status goes "down" if the backend is down.
> >
> > What is wrong? The docs? Am I misinterpreting the docs? Bug?
> 
> Which version are yor running? healthCheckMode wil only be available
> in 1.8.0, which is not released yet. See
> https://dnsdist.org/reference/config.html?highlight=newserver#newServer

Oh I missed that comment about changes in 1.8.

Thanks
Klaus
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Re: [dnsdist] Backend Questions

2022-11-02 Thread Otto Moerbeek via dnsdist 
On Wed, Nov 02, 2022 at 01:38:10PM +0100, Klaus Darilion via dnsdist wrote:

> (resent to the list)
> 
> Hi Remi!
> 
> > On 07/10/2022 10:53, Klaus Darilion via dnsdist wrote:
> > 
> > > We use dnsdist with 1 single backend server (PDNS). So if this backend
> > > is overloaded, dnsdist will detect the backend as DOWN. Hence, the only
> > > server for this backend pool down. How will dnsdist behave if all
> > > servers for a backend pool are down? Will it stop senden queries to the
> > > backend, or will it still send queries to the DOWN server as there is no
> > > UP server available?
> > 
> > All of the built-in load balancing policies will stop forwarding queries
> > when all the servers in the selected pool are down. It would be possible
> > to write a custom load-balancing in Lua that does not do that, of
> > course, but I don't think that's what you want in that case.
> > 
> > > So it may be useful to disable healthchecks completely. How can this be
> > > done?
> > 
> > You can force a server in the "up" state using the 'setUp()' method, see
> > [1].
> 
> Shouldn't newServer(...healthCheckMode='UP') also work? In my case it does 
> not work. 
> I have set healthCheckMode='UP' but:
> showServers show status as "up" whereas after setUp() the status is "UP". And 
> it still does helathchecks and status goes "down" if the backend is down.
> 
> What is wrong? The docs? Am I misinterpreting the docs? Bug?

Which version are yor running? healthCheckMode wil only be available
in 1.8.0, which is not released yet. See 
https://dnsdist.org/reference/config.html?highlight=newserver#newServer

-Otto
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Re: [dnsdist] Backend Questions

2022-11-02 Thread Klaus Darilion via dnsdist 
(resent to the list)

Hi Remi!

> On 07/10/2022 10:53, Klaus Darilion via dnsdist wrote:
> 
> > We use dnsdist with 1 single backend server (PDNS). So if this backend
> > is overloaded, dnsdist will detect the backend as DOWN. Hence, the only
> > server for this backend pool down. How will dnsdist behave if all
> > servers for a backend pool are down? Will it stop senden queries to the
> > backend, or will it still send queries to the DOWN server as there is no
> > UP server available?
> 
> All of the built-in load balancing policies will stop forwarding queries
> when all the servers in the selected pool are down. It would be possible
> to write a custom load-balancing in Lua that does not do that, of
> course, but I don't think that's what you want in that case.
> 
> > So it may be useful to disable healthchecks completely. How can this be
> > done?
> 
> You can force a server in the "up" state using the 'setUp()' method, see
> [1].

Shouldn't newServer(...healthCheckMode='UP') also work? In my case it does not 
work. 
I have set healthCheckMode='UP' but:
showServers show status as "up" whereas after setUp() the status is "UP". And 
it still does helathchecks and status goes "down" if the backend is down.

What is wrong? The docs? Am I misinterpreting the docs? Bug?

Thanks
Klaus
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Re: [dnsdist] Backend Questions

2022-10-07 Thread Remi Gacogne via dnsdist 

Hello Klaus,

On 07/10/2022 10:53, Klaus Darilion via dnsdist wrote:

We use dnsdist with 1 single backend server (PDNS). So if this backend 
is overloaded, dnsdist will detect the backend as DOWN. Hence, the only 
server for this backend pool down. How will dnsdist behave if all 
servers for a backend pool are down? Will it stop senden queries to the 
backend, or will it still send queries to the DOWN server as there is no 
UP server available?


All of the built-in load balancing policies will stop forwarding queries 
when all the servers in the selected pool are down. It would be possible 
to write a custom load-balancing in Lua that does not do that, of 
course, but I don't think that's what you want in that case.


So it may be useful to disable healthchecks completely. How can this be 
done?


You can force a server in the "up" state using the 'setUp()' method, see 
[1].


My current config is a few years old tested with dnsdist 1.3. These 
days, dnsdist was faster when I added the listen port multiple times, 
and also add the single backend server multiple times, to have more 
receiver threads. For example:


Is it still (dnsdist 1.6/1.7) useful/necessary to add listenSockets and 
Backendserver multiple times to improve performance?


I'm afraid so, yes. We have been thinking about a better syntax/design 
for spawning multiple threads without having to duplicate the lines, but 
haven't settled on and implemented a new syntax yet. Ideally we would 
like to avoid breaking compatibility with existing setups, both for the 
configuration files and for the metrics, but we might have to make a 
breaking change in a new major version.


[1]: https://dnsdist.org/quickstart.html#changing-server-settings

--
Remi Gacogne
PowerDNS.COM BV - https://www.powerdns.com/



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[dnsdist] Backend Questions

2022-10-07 Thread Klaus Darilion via dnsdist 
Hello!

We use dnsdist with 1 single backend server (PDNS). So if this backend is 
overloaded, dnsdist will detect the backend as DOWN. Hence, the only server for 
this backend pool down. How will dnsdist behave if all servers for a backend 
pool are down? Will it stop senden queries to the backend, or will it still 
send queries to the DOWN server as there is no UP server available?

So it may be useful to disable healthchecks completely. How can this be done?


My current config is a few years old tested with dnsdist 1.3. These days, 
dnsdist was faster when I added the listen port multiple times, and also add 
the single backend server multiple times, to have more receiver threads. For 
example:
-- Open the same socket multiple times. This allows better load distribution
-- over all cores. Note: 1. setLocal(), dann addLocal()!
setLocal("192.174.68.96:53", { reusePort=true, tcpFastOpenSize=100 })
addLocal("192.174.68.96:53", { reusePort=true, tcpFastOpenSize=100 })

-- Define the Backend Server Pools. Define them multiple times to have multiple 
receiver threads
-- handling the responses from the Backend.
newServer{address='127.0.0.1:14001',name='pdns_1'}   -- this is the 
PowerDNS server
newServer{address='127.0.0.1:14001',name='pdns_2'}   -- this is the 
PowerDNS server


Is it still (dnsdist 1.6/1.7) useful/necessary to add listenSockets and 
Backendserver multiple times to improve performance?

Thanks
Klaus


--
Klaus Darilion, Head of Operations
nic.at GmbH, Jakob-Haringer-Straße 8/V
5020 Salzburg, Austria
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