[pgpool-hackers: 4219] Re: Proposal: Add trusted_server_command parameter

[Takuma Hoshiai]

Hi,

On 2022/10/28 16:30, Tatsuo Ishii wrote:
>> Hi,
>>
>> On 2022/10/27 16:38, Takuma Hoshiai wrote:
>>> 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?
>>
>> I think it's good!
>> But pgpool log messeges are suppressed, I fix debug and error messages
>> to your patch.
>> In addition, I add a regression test for trusted_server.
> 
> Great!
> 
> Very minor points:
> 
> +		{"trusted_server_command", CFGCXT_RELOAD, WATCHDOG_CONFIG,
> +			"Command to excute when communicate trusted server.",
> 
> communicate --> communicate with
> 
> +			CONFIG_VAR_TYPE_STRING, false, 0
> +		},
> 
> +					ereport(WARNING,
> +							(errmsg("watchdog failed to ping host\"%s\"", server->hostname)));
> 
> ping host --> ping host:


Thanks! I fix it too.

> 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>