[CRIU] Debugging the process to restore veth in a namespace

[Hui Kang]

Hi, Pavel
I used "--veth-pair veth101=veth100" when dumping and restoring a process.
veth101 is the device name in the process net namespace, veth100 is the
other end which is in the criu host.

After restore, I can see the ip address of veth101 is restored. However,
the veth end in the host (veth100) is not successfully restored. By "not
success", I mean the veth100 link is created, however, its state is DOWN
and no IP is assigned to the restore link. Only I manually set the link
state to UP and assigne IP, the two ends can talk to each other.
Moreover, the link index of veth100 is not the same as when I dump the
process. For example the index for veth101 and veth100 is 15 and 16 when I
dump the process. After restore, veth100's index becomes 17. Is this a bug
in CRIU? Thanks.


- Hui

Part of the restore log is below. It looks like veth100 failed to restore
on host due to RTNETLINK file exists. But after dump the process, I do not
see veth100 in the host.

(00.004652)      1: Restoring link lo type 1
(00.005715)      1: Restoring link veth101 type 2
(00.005743)      1: Restoring netdev veth101 idx 33
(00.005754)      1: Restore ll addr (62:../6) for device
(00.006534)      1: DEBUG Skip veth101/accept_local, val =0
(00.006562)      1: DEBUG Skip veth101/accept_redirects, val =1
(00.006574)      1: DEBUG Skip veth101/accept_source_route, val =1
(00.006584)      1: DEBUG Skip veth101/arp_accept, val =0
(00.006594)      1: DEBUG Skip veth101/arp_announce, val =0
(00.006604)      1: DEBUG Skip veth101/arp_filter, val =0
(00.006614)      1: DEBUG Skip veth101/arp_ignore, val =0
(00.006624)      1: DEBUG Skip veth101/arp_notify, val =0
(00.006633)      1: DEBUG Skip veth101/bootp_relay, val =0
(00.006644)      1: DEBUG Skip veth101/disable_policy, val =0
(00.006653)      1: DEBUG Skip veth101/disable_xfrm, val =0
(00.006664)      1: DEBUG Skip veth101/force_igmp_version, val =0
(00.006674)      1: DEBUG Skip veth101/forwarding, val =1
(00.006683)      1: DEBUG Skip veth101/igmpv2_unsolicited_report_interval,
val =10000
(00.006693)      1: DEBUG Skip veth101/igmpv3_unsolicited_report_interval,
val =1000
(00.006703)      1: DEBUG Skip veth101/log_martians, val =0
(00.006712)      1: DEBUG Skip veth101/medium_id, val =0
(00.006722)      1: DEBUG Skip veth101/promote_secondaries, val =0
(00.006733)      1: DEBUG Skip veth101/proxy_arp, val =0
(00.006742)      1: DEBUG Skip veth101/proxy_arp_pvlan, val =0
(00.006752)      1: DEBUG Skip veth101/route_localnet, val =0
(00.006762)      1: DEBUG Skip veth101/rp_filter, val =1
(00.006772)      1: DEBUG Skip veth101/secure_redirects, val =1
(00.006782)      1: DEBUG Skip veth101/send_redirects, val =1
(00.006793)      1: DEBUG Skip veth101/shared_media, val =1
(00.006803)      1: DEBUG Skip veth101/src_valid_mark, val =0
(00.006814)      1: DEBUG Skip veth101/tag, val =0
(00.006864)      1:     Running ip addr restore
RTNETLINK answers: File exists
RTNETLINK answers: File exists
:


On Mon, Aug 3, 2015 at 10:20 AM, Pavel Emelyanov <xemul at parallels.com>
wrote:

> On 07/31/2015 05:25 PM, Hui Kang wrote:
> > Thanks for pointing out this option. I tested it to checkpoint and
> restore my program. It seems that dumping is successful, but the restore
> fails. The detailed log message is as follows
> >
> > veth100: the link in the host''s namespace
> > veth101: the link in the child process''s namespace
> >
> > # criu  dump -t 3737 -vvvv --veth-pair veth101=veth100  -j
> >
> > ...
> > (00.043143) Dumping pstree (pid: 3737)
> > (00.092334) Writing stats
> > (00.092545) Dumping finished successfully
> >
> >
> > # criu restore -vvvv --veth-pair veth101=veth100
> > (00.043539)      1: Error (tty.c:333): tty: Found slave peer index 2
> without correspond master peer
>
> The -j option should be used on restore too.
>
>
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