Re: repmgr cannot bring up the standby database after switchover manaully

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From: Tayyab Fayyaz <[email protected]>
To: Fernando Hevia <[email protected]>
Cc: Chris Lee <[email protected]>
Cc: Imran Khan <[email protected]>
Cc: pgsql-admin <[email protected]>
Subject: Re: repmgr cannot bring up the standby database after switchover manaully
Date: Wed, 1 Oct 2025 12:03:36 -0700
Message-ID: <CAFVRaQ0zz-81jReYtOEo2pHXD0GzZ5sr6=mL7nOQ_EBZkRh8MA@mail.gmail.com> (raw)
In-Reply-To: <CAGYT1XRLUstysEBwWKNVVWrUJCfahCFgmzEkFwpjQmABOaMocg@mail.gmail.com>
References: <CAP0GqH7hYsFGmLg3Ge-_Lf_VEeES8yeHpOhSvn071=XRnmVxTw@mail.gmail.com>
	<CAFVRaQ3No2rEYjkuKsxNNMCP16_J_kjDm_pv0+CYwTLXsjE8OQ@mail.gmail.com>
	<CAC4eXDgNZM12t8OgKYhjbu_7NFcsu0qG5aTpdXmbN=fmmp-5Tw@mail.gmail.com>
	<CAP0GqH7oRXztf1Ti13usH9CEgBmMJ4mPMsOn+qacD8Adi+Dxew@mail.gmail.com>
	<CAGYT1XRLUstysEBwWKNVVWrUJCfahCFgmzEkFwpjQmABOaMocg@mail.gmail.com>

Hello Fernando,

In my recent experience, there was no issue starting the old primary—it
came up normally. However, it resulted in a split-brain situation where the
old primary continued to accept both read and write operations while still
assuming the other two nodes were replicas.

This issue occurred with the following environment:

   -

   *OS version:* RHEL 8.10
   -

   *Postgres DB version:* 14.9
   -

   *repmgr version:* 5.5.0

Tayyab

On Wed, Oct 1, 2025 at 11:52 AM Fernando Hevia <[email protected]> wrote:

>
> I have 2 postgresql servers. One is the primary and another one is the
>> standby. I am trying to setup repmgr to do the switchover manually.
>> Passwordless ssh have been setup for postgres ID on both servers.
>>
>> I use this command "repmgr standby switchover --log-level=DEBUG
>> --verbose". The standy database is able to promote to be the primary. For
>> the previous primary database, it was shutdown. It was not able to bring up
>> as standby by repmgr.
>
>
> In a switchover the primary server is shutdown and restarted as a standby
> server after the newly promoted primary (former secondary) node has been
> started.
> If the primary did not start, there must have been an issue since this is
> not the standard behavior for a switchover command.
>
> Have you checked the Postgres log file for the previous primary? You
> should find the startup failure cause in the log.
>
> Regards,
> Fernando
>
>
>
> El mié, 1 oct 2025 a la(s) 7:30 a.m., Chris Lee ([email protected])
> escribió:
>
>> Hi Tayyab,
>>
>> Thanks for your information . I also want to find out whether that is the
>> default behavior,  or I am not configuring repmgr correctly.
>>
>> Regards,
>> Chris
>>
>> On Wed, 1 Oct 2025, 18:12 Imran Khan, <[email protected]> wrote:
>>
>>> Hi Tayyab,
>>>
>>>  Is this a default behavior? We have 4 nodes cluster but never had issue
>>> in switchovers.
>>>
>>> Thanks,
>>> Imran
>>>
>>> On Wed, Oct 1, 2025, 1:10 PM Tayyab Fayyaz <[email protected]>
>>> wrote:
>>>
>>>> Hello Chris,
>>>>
>>>> I faced this issue it will not add automatically as standby you have to
>>>> add it manually.
>>>>
>>>> But I wrote a script which perform to add old primary as standby once
>>>> it's back online.
>>>>
>>>> Tayyab
>>>>
>>>>
>>>> On Wed, 1 Oct 2025, 3:02 pm Chris Lee, <[email protected]> wrote:
>>>>
>>>>> Hi all,
>>>>>
>>>>> I have 2 postgresql servers. One is the primary and another one is the
>>>>> standby. I am trying to setup repmgr to do the switchover manually.
>>>>> Passwordless ssh have been setup for postgres ID on both servers.
>>>>>
>>>>> I use this command "repmgr standby switchover --log-level=DEBUG
>>>>> --verbose". The standy database is able to promote to be the primary. For
>>>>> the previous primary database, it was shutdown. It was not able to bring up
>>>>> as standby by repmgr.
>>>>>
>>>>> Does anyone encounter this issue before? Thanks a lot for any
>>>>> suggestions.
>>>>>
>>>>> Here is my OS and DB versions:
>>>>>
>>>>> OS version: CentOS Stream release 8
>>>>> Postgres DB version:  15.12
>>>>> rempmgr version: 5.5.0
>>>>>
>>>>> Here is the repmgr conf files:
>>>>> >>>>>
>>>>> node_id=1  # Use 2 on standby
>>>>> node_name='primary'
>>>>> conninfo='host=centos804 user=repmgr dbname=repmgr password=xxx
>>>>> connect_timeout=15'
>>>>> use_primary_conninfo_password=true
>>>>> data_directory='/var/lib/pgsql/15/data'  # Adjust for your setup
>>>>> pg_bindir='/usr/pgsql-15/bin'
>>>>> service_start_command = 'sudo systemctl start postgresql-15'
>>>>> service_stop_command  = 'sudo systemctl stop postgresql-15'
>>>>> <<<<<
>>>>>
>>>>> >>>>>
>>>>> node_id=2  # Use 2 on standby
>>>>> node_name='standby'
>>>>> conninfo='host=centos803 user=repmgr dbname=repmgr password=xxx
>>>>> connect_timeout=15'
>>>>> use_primary_conninfo_password=true
>>>>> data_directory='/var/lib/pgsql/15/data'  # Adjust for your setup
>>>>> pg_bindir='/usr/pgsql-15/bin'
>>>>> service_start_command = 'sudo systemctl start postgresql-15'
>>>>> service_stop_command  = 'sudo systemctl stop postgresql-15'
>>>>> <<<<<
>>>>>
>>>>> Regards,
>>>>> Chris
>>>>>
>>>>

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