[pgpool-general: 2932] Re: pool members are reporting different backend states
Yugo Nagata
nagata at sraoss.co.jp
Thu Jun 19 19:08:00 JST 2014
Hi,
On Thu, 19 Jun 2014 11:05:32 +0200
Attila Heidrich <attila.heidrich at gmail.com> wrote:
> Dear Guys,
>
> How on earth it is possible, that the pool members reports different
> backend status? It will cause problems very soon I guess.
It is possible if pgpool reads old backend status info when this starts up.
pgpool will discard the old backend info when starts with -D option.
However, it would be better pgpools can detect the status mismatch
between them in some way.
>
> Node: 1
> Host: 10.100.1.11
> Port: 5433
> Weight: 0.500000
> Status: Up, in pool (1)
> WD status: Standby (2)
>
> Node: 2
> Host: 10.100.1.10
> Port: 5433
> Weight: 0.500000
> Status: Up, in pool (1)
>
> ---
>
> Node: 1
> Host: 10.100.1.11
> Port: 5433
> Weight: 0.500000
> Status: Up, detached from pool (3)
> WD status: Standby (2)
>
> Node: 2
> Host: 10.100.1.10
> Port: 5433
> Weight: 0.500000
> Status: Up, in pool (1)
> WD status: Standby (2)
>
> ---
>
> Node: 1
> Host: 10.100.1.11
> Port: 5433
> Weight: 0.500000
> Status: Up, in pool (1)
> WD status: Standby (2)
>
> Node: 2
> Host: 10.100.1.10
> Port: 5433
> Weight: 0.500000
> Status: Up, in pool (1)
> WD status: Active (3)
>
> ---
>
> Node: 1
> Host: 10.100.1.11
> Port: 5433
> Weight: 0.500000
> Status: Up, in pool (1)
> WD status: Standby (2)
>
> Node: 2
> Host: 10.100.1.10
> Port: 5433
> Weight: 0.500000
> Status: Up, in pool (1)
> WD status: Standby (2)
>
> ---
>
> Node: 1
> Host: 10.100.1.11
> Port: 5433
> Weight: 0.500000
> Status: Up, detached from pool (3)
> WD status: Standby (2)
>
> Node: 2
> Host: 10.100.1.10
> Port: 5433
> Weight: 0.500000
> Status: Up, in pool (1)
> WD status: Active (3)
>
> I have got five pool members, two of them are the backends themselves.
>
> Every pool member has the other 4 as other_pgpool, and
> heartbeat_destination, and the same two backend servers, here is the
> relevant part of the config for all pool members:
>
>
> nor-openfire-1:
> backend_hostname1 = '10.100.1.11'
> backend_port1 = 5433
> backend_weight1 = 1
> backend_data_directory1 = '/var/lib/postgresql/9.3'
> backend_flag1 = 'ALLOW_TO_FAILOVER'
> backend_hostname2 = '10.100.1.10'
> backend_port2 = 5433
> backend_weight2 = 1
> backend_data_directory2 = '/var/lib/postgresql/9.3'
> backend_flag2 = 'ALLOW_TO_FAILOVER'
> fail_over_on_backend_error = on
> heartbeat_destination0 = 'nor-postgres-2'
> heartbeat_destination_port0 = 9694
> other_pgpool_hostname0 = 'nor-postgres-2'
> other_pgpool_port0 = 5432
> heartbeat_destination1 = 'nor-jboss-2'
> heartbeat_destination_port1 = 9694
> other_pgpool_hostname1 = 'nor-jboss-2'
> other_pgpool_port1 = 5432
> heartbeat_destination2 = 'nor-postgres-1'
> heartbeat_destination_port2 = 9694
> other_pgpool_hostname2 = 'nor-postgres-1'
> other_pgpool_port2 = 5432
> heartbeat_destination3 = 'nor-jboss-1'
> heartbeat_destination_port3 = 9694
> other_pgpool_hostname3 = 'nor-jboss-1'
> other_pgpool_port3 = 5432
> nor-postgres-1:
> backend_hostname1 = '10.100.1.11'
> backend_port1 = 5433
> backend_weight1 = 1
> backend_data_directory1 = '/var/lib/postgresql/9.3'
> backend_flag1 = 'ALLOW_TO_FAILOVER'
> backend_hostname2 = '10.100.1.10'
> backend_port2 = 5433
> backend_weight2 = 1
> backend_data_directory2 = '/var/lib/postgresql/9.3'
> backend_flag2 = 'ALLOW_TO_FAILOVER'
> fail_over_on_backend_error = on
> heartbeat_destination0 = 'nor-postgres-2'
> heartbeat_destination_port0 = 9694
> other_pgpool_hostname0 = 'nor-postgres-2'
> other_pgpool_port0 = 5432
> heartbeat_destination1 = 'nor-jboss-2'
> heartbeat_destination_port1 = 9694
> other_pgpool_hostname1 = 'nor-jboss-2'
> other_pgpool_port1 = 5432
> heartbeat_destination2 = 'nor-openfire-1'
> heartbeat_destination_port2 = 9694
> other_pgpool_hostname2 = 'nor-openfire-1'
> other_pgpool_port2 = 5432
> heartbeat_destination3 = 'nor-jboss-1'
> heartbeat_destination_port3 = 9694
> other_pgpool_hostname3 = 'nor-jboss-1'
> other_pgpool_port3 = 5432
> nor-postgres-2:
> backend_hostname1 = '10.100.1.11'
> backend_port1 = 5433
> backend_weight1 = 1
> backend_data_directory1 = '/var/lib/postgresql/9.3'
> backend_flag1 = 'ALLOW_TO_FAILOVER'
> backend_hostname2 = '10.100.1.10'
> backend_port2 = 5433
> backend_weight2 = 1
> backend_data_directory2 = '/var/lib/postgresql/9.3'
> backend_flag2 = 'ALLOW_TO_FAILOVER'
> fail_over_on_backend_error = on
> heartbeat_destination0 = 'nor-jboss-2'
> heartbeat_destination_port0 = 9694
> other_pgpool_hostname0 = 'nor-jboss-2'
> other_pgpool_port0 = 5432
> heartbeat_destination1 = 'nor-openfire-1'
> heartbeat_destination_port1 = 9694
> other_pgpool_hostname1 = 'nor-openfire-1'
> other_pgpool_port1 = 5432
> heartbeat_destination2 = 'nor-postgres-1'
> heartbeat_destination_port2 = 9694
> other_pgpool_hostname2 = 'nor-postgres-1'
> other_pgpool_port2 = 5432
> heartbeat_destination3 = 'nor-jboss-1'
> heartbeat_destination_port3 = 9694
> other_pgpool_hostname3 = 'nor-jboss-1'
> other_pgpool_port3 = 5432
> nor-jboss-1:
> backend_hostname1 = '10.100.1.11'
> backend_port1 = 5433
> backend_weight1 = 1
> backend_data_directory1 = '/var/lib/postgresql/9.3'
> backend_flag1 = 'ALLOW_TO_FAILOVER'
> backend_hostname2 = '10.100.1.10'
> backend_port2 = 5433
> backend_weight2 = 1
> backend_data_directory2 = '/var/lib/postgresql/9.3'
> backend_flag2 = 'ALLOW_TO_FAILOVER'
> fail_over_on_backend_error = on
> heartbeat_destination0 = 'nor-postgres-2'
> heartbeat_destination_port0 = 9694
> other_pgpool_hostname0 = 'nor-postgres-2'
> other_pgpool_port0 = 5432
> heartbeat_destination1 = 'nor-jboss-2'
> heartbeat_destination_port1 = 9694
> other_pgpool_hostname1 = 'nor-jboss-2'
> other_pgpool_port1 = 5432
> heartbeat_destination2 = 'nor-openfire-1'
> heartbeat_destination_port2 = 9694
> other_pgpool_hostname2 = 'nor-openfire-1'
> other_pgpool_port2 = 5432
> heartbeat_destination3 = 'nor-postgres-1'
> heartbeat_destination_port3 = 9694
> other_pgpool_hostname3 = 'nor-postgres-1'
> other_pgpool_port3 = 5432
> nor-jboss-2:
> backend_hostname1 = '10.100.1.11'
> backend_port1 = 5433
> backend_weight1 = 1
> backend_data_directory1 = '/var/lib/postgresql/9.3'
> backend_flag1 = 'ALLOW_TO_FAILOVER'
> backend_hostname2 = '10.100.1.10'
> backend_port2 = 5433
> backend_weight2 = 1
> backend_data_directory2 = '/var/lib/postgresql/9.3'
> backend_flag2 = 'ALLOW_TO_FAILOVER'
> fail_over_on_backend_error = on
> heartbeat_destination0 = 'nor-postgres-2'
> heartbeat_destination_port0 = 9694
> other_pgpool_hostname0 = 'nor-postgres-2'
> other_pgpool_port0 = 5432
> heartbeat_destination1 = 'nor-openfire-1'
> heartbeat_destination_port1 = 9694
> other_pgpool_hostname1 = 'nor-openfire-1'
> other_pgpool_port1 = 5432
> heartbeat_destination2 = 'nor-postgres-1'
> heartbeat_destination_port2 = 9694
> other_pgpool_hostname2 = 'nor-postgres-1'
> other_pgpool_port2 = 5432
> heartbeat_destination3 = 'nor-jboss-1'
> heartbeat_destination_port3 = 9694
> other_pgpool_hostname3 = 'nor-jboss-1'
> other_pgpool_port3 = 5432
>
> Other question:
>
> Our servers are connected via two networks. Is it possible to specify a
> pool member with both IP interfaces?
One other pgpool must be specified by single IP or hostname. You can use either
of them. The exception is heartbeat destination; you can specify both IP
as heartbeat_destinationX.
>
> ----------------------------------------------------------------------------------------
> Network #1
> | | | |
> |
> S1 S2 S3 S4 S5
> | | | |
> |
> ----------------------------------------------------------------------------------------
> Network #2
>
> none of the networks are connected with failover connections, both use
> different IP subnets.
>
> Regards,
>
> Attila
--
Yugo Nagata <nagata at sraoss.co.jp>
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