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

[Madison Kelly]

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/