Thread: [GENERAL] cluster question
Hi
I have setup a streaming replicating cluster, with a hot standby.
Now I would like to change the RW to hot standby and change the hot standby to be the RW server.
Is it just a matter of updating recover.conf file ?
Alex
On 14 August 2017 08:39:54 GMT+02:00, Alex Samad <alex@samad.com.au> wrote: >Hi > >I have setup a streaming replicating cluster, with a hot standby. > >Now I would like to change the RW to hot standby and change the hot >standby >to be the RW server. > >Is it just a matter of updating recover.conf file ? > >Alex I would suggest you repmgr, with this tool you can do "repmgr standby switchover" to perform such tasks. Regards, Andreas. -- 2ndQuadrant - The PostgreSQL Support Company
Hi
Quick question. I have a 2 node cluster - each node has its own ip.
But from reading this, I really need a 3rd ip, which potentially floats between the nodes to which ever is the master / rw node.
Is that right? Sort of makes sense I guess
A
On 14 August 2017 at 16:47, Andreas Kretschmer <andreas@a-kretschmer.de> wrote:
I would suggest you repmgr, with this tool you can do "repmgr standby switchover" to perform such tasks.On 14 August 2017 08:39:54 GMT+02:00, Alex Samad <alex@samad.com.au> wrote:
>Hi
>
>I have setup a streaming replicating cluster, with a hot standby.
>
>Now I would like to change the RW to hot standby and change the hot
>standby
>to be the RW server.
>
>Is it just a matter of updating recover.conf file ?
>
>Alex
Regards, Andreas.
--
2ndQuadrant - The PostgreSQL Support Company
Am 15.08.2017 um 05:15 schrieb Alex Samad: > Hi > > Quick question. I have a 2 node cluster - each node has its own ip. > > But from reading this, I really need a 3rd ip, which potentially > floats between the nodes to which ever is the master / rw node. > > Is that right? Sort of makes sense I guess > That's one way to solve that problem. If you are using repmgr/repmgrd you can call own commands on events like failover. And, if you are using pgbouncer or connection-pooling you can change the config for pgbouncer (redefine the databases and there connection strings) and reload pgbouncer. You can do that with the event-notification commands defined in your repmgr-config. Other solution: with some Java-drivers you can define several databases and checks (if the database read-only or rw), the next PostgreSQL 10 will offer a similar feature. PS.: please don't top-posting. Regards, Andreas -- 2ndQuadrant - The PostgreSQL Support Company. www.2ndQuadrant.com
On 15 August 2017 at 16:35, Andreas Kretschmer <andreas@a-kretschmer.de> wrote:
Am 15.08.2017 um 05:15 schrieb Alex Samad:Hi
Quick question. I have a 2 node cluster - each node has its own ip.
But from reading this, I really need a 3rd ip, which potentially floats between the nodes to which ever is the master / rw node.
Is that right? Sort of makes sense I guess
That's one way to solve that problem. If you are using repmgr/repmgrd you can call own commands on events like failover. And, if you are using pgbouncer or connection-pooling you can change the config for pgbouncer (redefine the databases and there connection strings) and reload pgbouncer. You can do that with the event-notification commands defined in your repmgr-config.
Other solution: with some Java-drivers you can define several databases and checks (if the database read-only or rw), the next PostgreSQL 10 will offer a similar feature.
okay think I have it setup, but when i do a switch over it gets stuck here.
NOTICE: STANDBY PROMOTE successful
NOTICE: Executing pg_rewind on old master server
NOTICE: 3 files copied to /var/lib/pgsql/9.6/data
NOTICE: restarting server using '/usr/pgsql-9.6/bin/pg_ctl -w -D /var/lib/pgsql/9.6/data -m fast restart'
pg_ctl: PID file "/var/lib/pgsql/9.6/data/postmaster.pid" does not exist
Is server running?
starting server anyway
NOTICE: STANDBY FOLLOW successful
doesn't look like the output from https://github.com/2ndQuadrant/repmgr/blob/master/README.md
NOTICE: STANDBY PROMOTE successful
NOTICE: Executing pg_rewind on old master server
NOTICE: 5 files copied to /var/lib/postgresql/9.5/data
NOTICE: restarting server using '/usr/local/bin/pg_ctl -w -D /var/lib/postgresql/9.5/node_1/data -m fast restart'
pg_ctl: PID file "/var/lib/postgresql/9.5/node_1/data/postmaster.pid" does not exist
Is server running?
starting server anyway
NOTICE: node 1 is replicating in state "streaming"
NOTICE: switchover was successful PS.: please don't top-posting.
Regards, Andreas
--
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www.2ndQuadrant.com
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On 08/16/2017 02:41 PM, Alex Samad wrote:
(...)
>
> okay think I have it setup, but when i do a switch over it gets stuck here.
>
>
>
> NOTICE: STANDBY PROMOTE successful
> NOTICE: Executing pg_rewind on old master server
> NOTICE: 3 files copied to /var/lib/pgsql/9.6/data
> NOTICE: restarting server using '/usr/pgsql-9.6/bin/pg_ctl -w -D /var/lib/pgsql/9.6/data -m fast restart'
> pg_ctl: PID file "/var/lib/pgsql/9.6/data/postmaster.pid" does not exist
> Is server running?
> starting server anyway
> NOTICE: STANDBY FOLLOW successful
From the repmgr README:
>> You must ensure that following a server start using `pg_ctl`, log output
>> is not send to STDERR (the default behaviour). If logging is not configured,
>> we recommend setting `logging_collector=on` in `postgresql.conf` and
>> providing an explicit `-l/--log` setting in `repmgr.conf`'s `pg_ctl_options`
>> parameter.
i.e. when the old primary is restarted with:
/usr/pgsql-9.6/bin/pg_ctl -w -D /var/lib/pgsql/9.6/data -m fast restart
the calling process hangs, waiting for logging output from pg_ctl.
In "repmgr.conf" set "pg_ctl_options" to something like:
pg_ctl_options='-l /path/to/log'
Regards
Ian Barwick
--
Ian Barwick http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
On 17 August 2017 at 10:51, Ian Barwick <ian.barwick@2ndquadrant.com> wrote:
On 08/16/2017 02:41 PM, Alex Samad wrote:
(...)
>
> okay think I have it setup, but when i do a switch over it gets stuck here.
>
>
>
> NOTICE: STANDBY PROMOTE successful
> NOTICE: Executing pg_rewind on old master server
> NOTICE: 3 files copied to /var/lib/pgsql/9.6/data
> NOTICE: restarting server using '/usr/pgsql-9.6/bin/pg_ctl -w -D /var/lib/pgsql/9.6/data -m fast restart'
> pg_ctl: PID file "/var/lib/pgsql/9.6/data/postmaster.pid" does not exist From the repmgr README:
> Is server running?
> starting server anyway
> NOTICE: STANDBY FOLLOW successful
>> You must ensure that following a server start using `pg_ctl`, log output
>> is not send to STDERR (the default behaviour). If logging is not configured,
>> we recommend setting `logging_collector=on` in `postgresql.conf` and
>> providing an explicit `-l/--log` setting in `repmgr.conf`'s `pg_ctl_options`
>> parameter.
i.e. when the old primary is restarted with:
/usr/pgsql-9.6/bin/pg_ctl -w -D /var/lib/pgsql/9.6/data -m fast restart
the calling process hangs, waiting for logging output from pg_ctl.
In "repmgr.conf" set "pg_ctl_options" to something like:
pg_ctl_options='-l /path/to/log'
Regards
Thanks, simple when you know, too many new things to look at
Ian Barwick
--
Ian Barwick http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services