[pgpool-general: 3516] Node disabled problems

James Sewell james.sewell at lisasoft.com
Mon Mar 16 16:19:19 JST 2015


Hey,

I am using PGpool on an AWS instance with the following settings:

backend_flag0 = 'ALLOW_TO_FAILOVER'
backend_flag1 = 'ALLOW_TO_FAILOVER'
failover_command = ''
failback_command = ''
fail_over_on_backend_error = off

I am managing failovers from an external product (EDB Enterprise Failover
Manager). This seems to work well most of the time.

Sometimes I get the master node failing because of the AWS network flaking
out on me, this works as expected and I get into the following state:

postgres=# show pool_nodes;
 node_id |   hostname   | port | status | lb_weight |  role
---------+--------------+------+--------+-----------+---------
 0       | 10.51.9.174  | 5432 | 3      | 0.500000  | primary
 1       | 10.51.10.173 | 5432 | 2      | 0.500000  | standby
(2 rows)

My question is, is there any way in PGPool to automatically re-enable the
primary node when it shows up again? If it *really* went down then my EFM
would fail it over (which runs pcp_promote_node) - so I just want it to
enable it when it shows up again. I can't explain why EFM seems to be more
fault tolerant than PGPool - but I'm ignoring that for now.

I tried using DISALLOW_TO_FAILOVER , but this removes any way of disabling
a single node and stops all PGPool access when I stop the standby node.
This won't work for me. I need to be able to perform the following
operations:

   - promote a node in PGPool to master (I use pcp_promote_node currently)
   - disable a node in PGPool (I use pcp_detach_node currently)
   - enable a node I have disabled (I use pcp_enable_node currently)
   - Operate on just the master node
   - Operate on just the slave node (read only)

I can't seem to find a way to hit all these and still have a functioning
environment.

I'm getting the feeling that maybe I can't get all this from PGPool, but
any help would be appreciated. I'm on PGPool 3.3.1

Cheers,


James Sewell,
PostgreSQL Team Lead / Solutions Architect
______________________________________


 Level 2, 50 Queen St, Melbourne VIC 3000

*P *(+61) 3 8370 8000  *W* www.lisasoft.com  *F *(+61) 3 8370 8099

-- 


------------------------------
The contents of this email are confidential and may be subject to legal or 
professional privilege and copyright. No representation is made that this 
email is free of viruses or other defects. If you have received this 
communication in error, you may not copy or distribute any part of it or 
otherwise disclose its contents to anyone. Please advise the sender of your 
incorrect receipt of this correspondence.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.sraoss.jp/pipermail/pgpool-general/attachments/20150316/a58b5666/attachment.html>


More information about the pgpool-general mailing list