Re: What's going on with vnets and epairs w/ addresses?

Hi,

I also encounter this problem while testing gif tunnel between jails.

My script is similar but with additional gif tunnels.


There are reports in mailing list [1], [2], and another one in forum [3] .

Seem to be a long standing issue.

[1] https://lists.freebsd.org/pipermail/freebsd-stable/2016-October/086126.html <https://lists.freebsd.org/pipermail/freebsd-stable/2016-October/086126.html>
[2] https://lists.freebsd.org/pipermail/freebsd-jail/2017-March/003357.html <https://lists.freebsd.org/pipermail/freebsd-jail/2017-March/003357.html>
[3] https://forums.freebsd.org/threads/jails-stopping-prolonged-deaths-starting-networking-et-cetera.84200/ <https://forums.freebsd.org/threads/jails-stopping-prolonged-deaths-starting-networking-et-cetera.84200/>


Best regards,
Zhenlei

> On Dec 14, 2022, at 7:03 AM, Bjoern A. Zeeb <bz@FreeBSD.org> wrote:
> 
> Hi,
> 
> I have used scripts like the below for almost a decade and a half
> (obviously doing more than that in the middle).  I haven't used them
> much lately but given other questions I just wanted to fire up a test.
> 
> I have an end-November kernel doing the below my eapirs do not come back
> to be destroyed (immediately).
> I have to start polling for the jid to be no longer alive and not in
> dying state (hence added the jls/ifconfig -l lines and removed the
> error checking from ifconfig destroy).  That seems sometimes rather
> unreasonably long (to the point I give up).
> 
> If I don't configure the addresses below this isn't a problem.
> 
> Sorry I am confused by too many incarnations of the code; I know I once
> had a version with an async shutdown path but I believe that never made
> it into mainline, so why are we holding onto the epairs now and not
> nuking the addresses and returning them and are clean?
> 
> It's a bit more funny; I added a twiddle loop at the end and nothing
> happened.  So I stop the script and start it again and suddenly another
> jail or two have cleaned up and their epairs are back.  Something feels
> very very wonky.  Play around with this and see ... and let me know if
> you can reproduce this...  I quite wonder why some test cases haven't
> gone crazy ...
> 
> /bz
> 
> ------------------------------------------------------------------------
> #!/bin/sh
> 
> set -e
> set -x
> 
> js=`jail -i -c -n jl host.hostname=left.example.net vnet persist`
> jb=`jail -i -c -n jr host.hostname=right.example.net vnet persist`
> 
> # Create an epair connecting the two machines (vnet jails).
> ep=`ifconfig epair create | sed -e 's/a$//'`
> 
> # Add one end to each vnet jail.
> ifconfig ${ep}a vnet ${js}
> ifconfig ${ep}b vnet ${jb}
> 
> # Add an IP address on the epairs in each vnet jail.
> # XXX Leave these out and the cleanup seems to work fine.
> jexec ${js}  ifconfig ${ep}a inet  192.0.2.1/24
> jexec ${jb}  ifconfig ${ep}b inet  192.0.2.2/24
> 
> # Clean up.
> jail -r ${jb}
> jail -r ${js}
> 
> # You want to be able to remove this line ...
> set +e
> 
> # No epairs to destroy with addresses configured; fine otherwise.
> ifconfig ${ep}a destroy
> # echo $?
> 
> # Add this is here only as things are funny ...
> # jls -av jid dying
> # ifconfig -l
> 
> # end
> ------------------------------------------------------------------------
> 
> -- 
> Bjoern A. Zeeb                                                     r15:7
>