<div dir="ltr"><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">Hi <span style="background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">Piotr,</span></div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial"><br></div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">The purpose of trusted_servers is to make sure the Pgpool-II node which gets isolated from</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">network because of some network partitioning remove itself from the Pgpool-II cluster.</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">Suppose in some hypothetical environment one wants that every Pgpool-II node should remain</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">connected or can access the internet or public network, so that users from other networks can access the service,</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">while at the same time watchdog use the internal private network (delegate-ip would be public IP in this case).</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">So the way to verify the connectivity of Pgpool-II node with external network or internet is to use trusted_servers config.</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">for example you can use '<a href="http://pgpool.net">pgpool.net</a>' in trusted server list to ensure that Pgpool-II node is not isolated from</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">internet and able to ping the public website on internet. and as soon as the node fail to ping the <a href="http://pgpool.net">pgpool.net</a> it will</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">declare itself dead even if it can reach the other pgpool nodes on local network.</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial"><br></div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">trusted_servers config could be used to mitigate the split-brain syndrome in older versions of Pgpool-II but</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">if you are on 3.6.7 which has the quorum aware watchdog system you don't require to use trusted_servers config</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">and leave it empty, of course if you don't have some other specific requirements as the one I described in above example.</div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial"><br></div><div style="font-size:small;text-decoration-style:initial;text-decoration-color:initial">Please let me know if you need further clarification or explanation.</div><br class="gmail-Apple-interchange-newline"><div>Thanks</div><div>Best Regards</div><div>Muhammad Usama</div><br><br><div class="gmail_quote"><div dir="ltr">On Mon, Jul 23, 2018 at 7:55 PM Piotr Gbyliczek <<a href="mailto:P.Gbyliczek@node4.co.uk">P.Gbyliczek@node4.co.uk</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>Hi, <br>
<br>
Sorry for reviving old thread, but I've recently gone up to 3.6.7 and observed <br>
same behavior. <br>
<br>
As I understand it, trusted_servers is a mechanism that should prevent standby <br>
pgpool service to bring up the delegated IP, and cause split brain where there <br>
is a network partition between pgpool servers. </div></blockquote><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div>
<br>
But struggling to see why standby that is able to communicate with it's master <br>
over watchdog channel would declare itself dead upon failing to contact <br>
trusted_servers. <br>
<br>
In fact I've had two scenarios : <br>
- standby pgpool declared itself dead on failing to contact trusted server, <br>
which was discovered when master pgpool was manually stopped and there was no <br>
standby to fall back to.<br>
- master declared itself dead on failing to contact trusted server, which <br>
initiated failover procedure and standby picked up the master role, bringing <br>
up the delegated IP. this is correct behavior in general, but have been <br>
noticed by customers and monitoring, hence some question have been raised. <br>
<br>
I would say both could be avoided, and were unnecessary downtime for the <br>
delegated IP. <br>
<br>
Was there any conclusion to this issue, or design explanation to the behavior <br>
? <br>
<br>
Thanks, <br>
Piotr<br>
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