<html><head></head><body><div style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div><div>To prevent this split brain scenario (caused by a network partition) you can use the configuration trusted_servers. This setting is a list of servers that pgpool can use to determine if a node is suffering a network partition or not. If a node cannot reach any of the servers in the list, then it will assume it is isolated (by a network partition) and will not promote itself to master.</div><div><br></div><div>In general, when you have only two nodes, it is not safe to do an automatic failover I believe. Unless you have some kind of fencing mechanism (means: you can shutdown and prevent a failed node to come back after a failure).</div><div><br></div><div class="ydp2a8d5a3csignature">Pierre</div></div>
<div><br></div><div><br></div>
<div id="ydp44fa9843yahoo_quoted_0647994684" class="ydp44fa9843yahoo_quoted">
<div style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:13px;color:#26282a;">
<div>
On Tuesday, February 27, 2018, 7:58:55 PM GMT+1, Alexander Dorogensky <amazinglifetime@gmail.com> wrote:
</div>
<div><br></div>
<div><br></div>
<div><div id="ydp44fa9843yiv4431463748"><div dir="ltr"><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;">Hi All,<br><br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;">I have a <a href="http://10.0.0.1/10.0.0.2" rel="nofollow" target="_blank">10.0.0.1/10.0.0.2</a> master/hot standby configuration with streaming replication, where each node runs pgpool with watchdog enabled and postgres.<br><br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;">I shut down the network interface on 10.0.0.1 and wait until 10.0.0.2 triggers failover and promotes itself to master through my failover script.<br><br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;">Now the watchdogs on 10.0.0.1 and 10.0.0.2 are out of sync, have conflicting views on which node has failed and both think they are master.<br><br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;">When I bring back the network interface on 10.0.0.1, 'show pool_nodes' says that 10.0.0.1 is master/up and 10.0.0.2 is standby/down. <br><br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;">I want 10.0.0.1 to be standby and 10.0.0.2 to be master. <br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;"><br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;">I've been playing with the failover script.. e.g.<br><br>if (default network gateway is pingable) {<br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;"> shut down pgpool and postgres<br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;">} else if (this node is standby) {<br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;"> promote this node to master<br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;"> create a job that will run every minute and try to recover failed node (base backup) <br> cancel the job upon successful recovery<br>} <br><br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;">Can you please help me with this? Any ideas would be highly appreciated.<br><br></div><div class="ydp44fa9843yiv4431463748gmail_default" style="font-family:new, monospace;">Regards, Alex<br></div></div></div>_______________________________________________<br>pgpool-general mailing list<br><a href="mailto:pgpool-general@pgpool.net" rel="nofollow" target="_blank">pgpool-general@pgpool.net</a><br><a href="http://www.pgpool.net/mailman/listinfo/pgpool-general" rel="nofollow" target="_blank">http://www.pgpool.net/mailman/listinfo/pgpool-general</a><br></div>
</div>
</div></div></body></html>