[pgpool-hackers: 4214] Re: Proposal: Add trusted_server_command parameter

[Tatsuo Ishii]

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?

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