[pgpool-hackers: 4215] Re: Proposal: Add trusted_server_command parameter

[Takuma Hoshiai]

Hi Ishii-san,

On 2022/10/27 16:20, Tatsuo Ishii wrote:
> Hoshiai-san,
> 
>>> Hi all,
>>>
>>> I create a patch about trusted_servers for v4.4.
>>> Add new parameter 'trusted_server_command'.
>>>
>>> Currently, only 'ping' command is used by trusted_servers for checking
>>> up stream
>>> connection, and number of sending packets is hard coded. In some
>>> cases, user maybe
>>> want to use other command.
>>>
>>> The trusted_server_command allow users to any specify command.　
>>> Default is
>>> 'ping -q -c %h' which means same as before.　Pgpool-II replaces the
>>> special
>>> characters(%h) with the host name in trusted_servers.
>>
>> I have tested your patch and encountered an issue. Can you please
>> help?
>>
>> I ran watchdog_setup to create a 3-pgpool-node cluster. And added
>> following two lined to each pgpool.conf then ran ./startall.
>>
>> trusted_servers = 'localhost'
>> trusted_server_command = 'ping -q -c3 %h'
>>
>> However the cluster did not start. I found following in the
>> pgpool.log.
>>
>> ping: write error: Bad file descriptor
>> 2022-10-27 13:35:29.855: watchdog_utility pid 326297: FATAL:  watchdog failed to ping host"localhost"
>> 2022-10-27 13:35:29.855: watchdog_utility pid 326297: DETAIL:  system(ping -q -c3 localhost) failed. reason: Success
>> 2022-10-27 13:35:29.856: life_check pid 326157: WARNING:  watchdog lifecheck, failed to connect to any trusted servers
>> 2022-10-27 13:35:29.856: life_check pid 326157: LOG:  informing the node status change to watchdog
>> 2022-10-27 13:35:29.856: life_check pid 326157: DETAIL:  node id :0 status = "NODE DEAD" message:"trusted server is unreachable"
>>
>> If I ran "ping -q -c3 localhost" manually, it works fine.
>>
>> $ ping -q -c3 localhost
>> PING localhost (127.0.0.1) 56(84) bytes of data.
>>
>> --- localhost ping statistics ---
>> 3 packets transmitted, 3 received, 0% packet loss, time 2034ms
>> rtt min/avg/max/mdev = 0.082/0.087/0.095/0.005 ms
> 
> I think wd_trusted_server_command() needs to assign appropreate fd
> (/dev/null) to stdin, stdout and stderr. Attached is the revised
> patch. Can you please check?

Thank you for your suggestion. I will check it.

> Best reagards,
> --
> Tatsuo Ishii
> SRA OSS LLC
> English: http://www.sraoss.co.jp/index_en/
> Japanese:http://www.sraoss.co.jp
> 

Best Regards,

-- 
Takuma Hoshiai <hoshiai.takuma at nttcom.co.jp>