[ClusterLabs] Failed 'virsh' call when test RA run by crm_resource (con't)

[Vladislav Bogdanov]

What would be the reason of running that command without redirecting its 
output somewhere?


Madison Kelly <mkelly at alteeve.com> 12 января 2023 г. 07:21:44 написал:

> On 2023-01-12 01:12, Reid Wahl wrote:
>> On Wed, Jan 11, 2023 at 8:11 PM Madison Kelly <mkelly at alteeve.com> wrote:
>>>
>>> Hi all,
>>>
>>>     There was a lot of sub-threads, so I figured it's helpful to start a
>>> new thread with a summary so far. For context; I have a super simple
>>> perl script that pretends to be an RA for the sake of debugging.
>>>
>>> https://pastebin.com/9z314TaB
>>>
>>>     I've had variations log environment variables and confirmed that all
>>> the variables in the direct call that work are in the crm_resource
>>> triggered call. There are no selinux issues logged in audit.log and
>>> selinux is permissive. The script logs the real and effective UID and
>>> GID and it's the same in both instances. Calling other shell programs
>>> (tested with 'hostname') run fine, this is specifically crm_resource ->
>>> test RA -> virsh call.
>>>
>>>     I ran strace on the virsh call from inside my test script (changing
>>> 'virsh.good' to 'virsh.bad' between running directly and via
>>> crm_resource. The strace runs made six files each time. Below are
>>> pastebin links with the outputs of the six runs in one paste, but each
>>> file's output is in it's own block (search for file: to see the
>>> different file outputs)
>>>
>>> Good/direct run of the test RA:
>>> - https://pastebin.com/xtqe9NSG
>>>
>>> Bad/crm_resource triggered run of the test RA:
>>> - https://pastebin.com/vBiLVejW
>>>
>>> Still absolutely stumped.
>>
>> The strace outputs show that your bad runs are all getting stopped
>> with SIGTTOU. If you've never heard of that, me either.
>
> The hell?! This is new to me also.
>
>> https://www.gnu.org/software/libc/manual/html_node/Job-Control-Signals.html
>>
>> Macro: int SIGTTOU
>>
>>      This is similar to SIGTTIN, but is generated when a process in a
>> background job attempts to write to the terminal or set its modes.
>> Again, the default action is to stop the process. SIGTTOU is only
>> generated for an attempt to write to the terminal if the TOSTOP output
>> mode is set; see Output Modes.
>>
>>
>> Maybe this has something to do with the buffer settings in the perl
>> script(?). It might be worth trying a version that doesn't fiddle with
>> the outputs and buffer settings.
>
> I tried removing the $|, and then I changed the script to be entirely a
> bash script, still hanging. I tried 'virsh --connect <method> list
> --all' where method was qemu:///system, qemu:///session, and
> ssh+qemu:///root@localhost/system, all hang. In bash or perl.
>
>> I don't know which difference between your environment and mine is
>> relevant here, such that I can't reproduce the issue using your test
>> script. It works perfectly fine for me.
>>
>> Can you run `stty -a | grep tostop`? If there's a minus sign
>> ("-tostop"), it's disabled; if it's present without a minus sign
>> ("tostop"), it's enabled, as best I can tell.
>
> -tostop is there
>
> ====
> [root at mk-a07n02 ~]# stty -a | grep tostop
> isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt
> [root at mk-a07n02 ~]#
> ====
>
>> I'm just spitballing here. It's disabled by default on my machine...
>> but even when I enable it, crm_resource --validate works fine. It may
>> be set differently when running under crm_resource.
>
> How do you enable it?
>
> --
> Madison Kelly
> Alteeve's Niche!
> Chief Technical Officer
> c: +1-647-471-0951
> https://alteeve.com/
>
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