Mailing List Archive

[lvs-users] R: How ldirectord polls real servers
In case of tcp protocol, in order to check the connection of a service of
mine running on realserevrs ("service=none") I already set " connect" as a
checktype; so I assume this setting is the best choice even if such service
should be configured for udp communication.

Should such service be stopped for some reason, my hope is its node should
be removed from the ldirector's realservers list

Thank you all for your time
Regards
G.

-----Messaggio originale-----
Da: lvs-users-bounces@linuxvirtualserver.org
[mailto:lvs-users-bounces@linuxvirtualserver.org] Per conto di Malcolm
Turnbull
Inviato: martedì 23 aprile 2013 18:26
A: LinuxVirtualServer.org users mailing list.
Oggetto: Re: [lvs-users] How ldirectord polls real servers

Gugliemo,

Ldirectord has various different health checking methods.

For a simple TCP based service you could use the 'connect' check i.e.
Can I do a TCP open on that port?
For UDP you would probably just use a ping check as it is connectionless.

The various methods are pretty well documented in the man page.


On 23 April 2013 16:42, Guglielmo Abbruzzese <g.abbruzzese@resi.it> wrote:
> Hi,
> as far as you know where can I find a detailed
> description/documentation about how ldirectord polls the realservers
> in order to realize if the node should be actually removed from the
cluster?
>
> For sure, " ldirectord monitors the health of the real servers by
> periodically requesting a known URL and checking that the response
> contains an expected response. If a real server fails then the server
> is removed and will be reactivated once it comes back on line.".
>
> But what if the real servers implement a custom tcp or udp service?
> In case of a tcp persistent connection, what if there is no data flow
> for a while (shall I rely just on the 'persistent' timeout)?
> And what about a cistom udp server?
>
> Is there a way to use tcpdump in order to detect such evidence?
>
> Thanks in advance for your advice,
> Regards
> G.
>
>
>
> _______________________________________________
> Please read the documentation before posting - it's available at:
> http://www.linuxvirtualserver.org/
>
> LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
> Send requests to lvs-users-request@LinuxVirtualServer.org
> or go to http://lists.graemef.net/mailman/listinfo/lvs-users



--
Regards,

Malcolm Turnbull.

Loadbalancer.org Ltd.
Phone: +44 (0)870 443 8779
http://www.loadbalancer.org/

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

LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org Send
requests to lvs-users-request@LinuxVirtualServer.org
or go to http://lists.graemef.net/mailman/listinfo/lvs-users


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

LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
Send requests to lvs-users-request@LinuxVirtualServer.org
or go to http://lists.graemef.net/mailman/listinfo/lvs-users
Re: [lvs-users] R: How ldirectord polls real servers [ In reply to ]
There's always the ultime solution, create your own check (sometimes needed
for debugging purpose) :

checktype=external
checkport=443
checkcommand="/usr/local/bin/check_mu_udp_server.sh"

which script may receive :
# $1 : IP virt
# $2 : Port virt
# $3 : IP real
# $4 : Port real
and just need to retun a value.

Hope usefull...


2013/4/24 Guglielmo Abbruzzese <g.abbruzzese@resi.it>

> In case of tcp protocol, in order to check the connection of a service of
> mine running on realserevrs ("service=none") I already set " connect" as a
> checktype; so I assume this setting is the best choice even if such service
> should be configured for udp communication.
>
> Should such service be stopped for some reason, my hope is its node should
> be removed from the ldirector's realservers list
>
> Thank you all for your time
> Regards
> G.
>
> -----Messaggio originale-----
> Da: lvs-users-bounces@linuxvirtualserver.org
> [mailto:lvs-users-bounces@linuxvirtualserver.org] Per conto di Malcolm
> Turnbull
> Inviato: martedì 23 aprile 2013 18:26
> A: LinuxVirtualServer.org users mailing list.
> Oggetto: Re: [lvs-users] How ldirectord polls real servers
>
> Gugliemo,
>
> Ldirectord has various different health checking methods.
>
> For a simple TCP based service you could use the 'connect' check i.e.
> Can I do a TCP open on that port?
> For UDP you would probably just use a ping check as it is connectionless.
>
> The various methods are pretty well documented in the man page.
>
>
> On 23 April 2013 16:42, Guglielmo Abbruzzese <g.abbruzzese@resi.it> wrote:
> > Hi,
> > as far as you know where can I find a detailed
> > description/documentation about how ldirectord polls the realservers
> > in order to realize if the node should be actually removed from the
> cluster?
> >
> > For sure, " ldirectord monitors the health of the real servers by
> > periodically requesting a known URL and checking that the response
> > contains an expected response. If a real server fails then the server
> > is removed and will be reactivated once it comes back on line.".
> >
> > But what if the real servers implement a custom tcp or udp service?
> > In case of a tcp persistent connection, what if there is no data flow
> > for a while (shall I rely just on the 'persistent' timeout)?
> > And what about a cistom udp server?
> >
> > Is there a way to use tcpdump in order to detect such evidence?
> >
> > Thanks in advance for your advice,
> > Regards
> > G.
> >
> >
> >
> > _______________________________________________
> > Please read the documentation before posting - it's available at:
> > http://www.linuxvirtualserver.org/
> >
> > LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
> > Send requests to lvs-users-request@LinuxVirtualServer.org
> > or go to http://lists.graemef.net/mailman/listinfo/lvs-users
>
>
>
> --
> Regards,
>
> Malcolm Turnbull.
>
> Loadbalancer.org Ltd.
> Phone: +44 (0)870 443 8779
> http://www.loadbalancer.org/
>
> _______________________________________________
> Please read the documentation before posting - it's available at:
> http://www.linuxvirtualserver.org/
>
> LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.orgSend
> requests to lvs-users-request@LinuxVirtualServer.org
> or go to http://lists.graemef.net/mailman/listinfo/lvs-users
>
>
> _______________________________________________
> Please read the documentation before posting - it's available at:
> http://www.linuxvirtualserver.org/
>
> LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
> Send requests to lvs-users-request@LinuxVirtualServer.org
> or go to http://lists.graemef.net/mailman/listinfo/lvs-users
>



--
Ivan

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

LinuxVirtualServer.org mailing list - lvs-users@LinuxVirtualServer.org
Send requests to lvs-users-request@LinuxVirtualServer.org
or go to http://lists.graemef.net/mailman/listinfo/lvs-users