[CRIU] Do anyone knows how to migrate a container with web app

Ross Boucher rboucher at gmail.com
Tue May 3 09:25:25 PDT 2016


I have not provided the modified CRIU in that release. This is a very hacky
way to simply drop sockets you can try:
https://github.com/boucher/criu/commit/0539fbc68228903ad4a2cae2b3737c6e888ab93d


On Tue, May 3, 2016 at 12:19 PM Weicheng SUN <sunweicheng0001 at gmail.com>
wrote:

> Thankfully, You understand what I mean. I know that I should request a
> same IP address and the CRIU I use is the release you give in cr-combined(I
> guess this is the modified CRIU you mentioned).
> The problem is I do not know how to request a container with specific IP
> address via docker command or RESTful API. I know there is docker run --ip
> for later than docker v1.10, but the latest release of cr-combined doesn't
> support this flag.
> I tried to modified the source code of docker v1.10, but it always hangs
> on without any response while running, :(.
> Do you know how to request such a container with the release version you
> give?
>
> Regards,
>
> David Sun 孙炜程
> School of Software Engineering, Shanghai Jiaotong University
>
> Mobile:  15921638078
>
> E-mail:  SunWeicheng0001 at gmail.com
>
> 2016-05-04 0:09 GMT+08:00 Ross Boucher <rboucher at gmail.com>:
>
>> What we've done is modified the CRIU source to simply drop these
>> unrestorable connections, rather than error out. Perhaps that could be
>> turned into an option.
>>
>> On Tue, May 3, 2016 at 12:08 PM Ross Boucher <rboucher at gmail.com> wrote:
>>
>>> You should be able to request the same IP when creating the new docker
>>> container. Similarly, you could do the same for any linked containers.
>>>
>>> On Tue, May 3, 2016 at 12:07 PM Weicheng SUN <sunweicheng0001 at gmail.com>
>>> wrote:
>>>
>>>> I know what you mean. But I just want to migrate some containers to
>>>> another host, all of those application can deal tcp reconnection.
>>>> You say if there are some packets cannot deliver into new container's
>>>> location, the restore will broken.
>>>> So, If there is* a method to skip this progress, just to bind the old
>>>> ip address to the container on the new host.*
>>>> Everytime I checkpoint a container with tcp connection, scp to another
>>>> host, then restore, the restore log always say that
>>>>
>>>> (00.294516)      1: Found id pipe:[6392267] (fd 1) in inherit fd list
>>>> (00.294520)      1: File pipe:[6392267] will be restored from fd 3
>>>> dumped from inherit fd 1
>>>> (00.294535)      1: Found fd 1 (id pipe:[6392267]) in inherit fd list
>>>> (caller inherit_fd_resolve_clash)
>>>> (00.294538)      1: Inherit fd 1 moved to 3 to resolve clash
>>>> (00.294541)      1:             Create fd for 1
>>>> (00.294544)      1:     Restoring fd 2 (state -> create)
>>>> (00.294545)      1:             Creating pipe pipe_id=0x6189cc id=0x3
>>>> (00.294547)      1: Found id pipe:[6392268] (fd 2) in inherit fd list
>>>> (00.294548)      1: File pipe:[6392268] will be restored from fd 4
>>>> dumped from inherit fd 2
>>>> (00.294554)      1: Found fd 2 (id pipe:[6392268]) in inherit fd list
>>>> (caller inherit_fd_resolve_clash)
>>>> (00.294555)      1: Inherit fd 2 moved to 4 to resolve clash
>>>> (00.294558)      1:             Create fd for 2
>>>> (00.294560)      1:     Restoring fd 4 (state -> create)
>>>> (00.294569)      1:     Restore: family 10 type 1 proto 6 port 6379
>>>> state 10 src_addr ::
>>>> (00.294592)      1: 5 restore sndbuf 16384 rcv buf 87380
>>>> (00.294595)      1:     restore priority 0 for socket
>>>> (00.294596)      1:     restore rcvlowat 1 for socket
>>>> (00.294598)      1:     restore mark 0 for socket
>>>> (00.294611)      1: Found fd 4 (id pipe:[6392268]) in inherit fd list
>>>> (caller inherit_fd_resolve_clash)
>>>> (00.294616)      1: Inherit fd 4 moved to 6 to resolve clash
>>>> (00.294619)      1:             Create fd for 4
>>>> (00.294622)      1:     Restoring fd 5 (state -> create)
>>>> (00.294625)      1:     Restore: family 2 type 1 proto 6 port 6379
>>>> state 10 src_addr 0.0.0.0
>>>> (00.294633)      1: 5 restore sndbuf 16384 rcv buf 87380
>>>> (00.294635)      1:     restore priority 0 for socket
>>>> (00.294636)      1:     restore rcvlowat 1 for socket
>>>> (00.294638)      1:     restore mark 0 for socket
>>>> (00.294640)      1:             Create fd for 5
>>>> (00.294642)      1:     Restoring fd 6 (state -> create)
>>>> (00.294644)      1:     Restore: family 2 type 1 proto 6 port 6379
>>>> state 1 src_addr 172.17.128.2
>>>> (00.294646)      1: Restoring TCP connection
>>>> (00.294649)      1: Restoring TCP connection id 7 ino 619526
>>>> (00.294657)      1:     Setting 1 queue seq to 2786935679
>>>> (00.294659)      1:     Setting 2 queue seq to 919486667
>>>> (00.294679)      1: Error (sk-inet.c:721): Can't bind inet socket (id
>>>> 7): Cannot assign requested address
>>>>
>>>> You see, 172.17.128.2 is the old ip, criu tried to bind this ip to new
>>>> container, but failed.
>>>>
>>>> Regards,
>>>>
>>>> David Sun 孙炜程
>>>> School of Software Engineering, Shanghai Jiaotong University
>>>>
>>>> Mobile:  15921638078
>>>>
>>>> E-mail:  SunWeicheng0001 at gmail.com
>>>>
>>>> 2016-04-28 18:33 GMT+08:00 Pavel Emelyanov <xemul at virtuozzo.com>:
>>>>
>>>>> On 04/28/2016 08:01 AM, Weicheng SUN wrote:
>>>>> > Hi Everyone,
>>>>> >
>>>>> > The latest release of cr-combined said that it supports network.
>>>>> Then I do some experiments. I use
>>>>> > 1. docker run -d -v demo:/data --name=redis redis:latest
>>>>> > 2. docker run -d -e USE_REDIS_HOST=redis --link redis:redis -p 80:80
>>>>> --name=app binocarlos/moby-counter:latest
>>>>> > which is a demo of simple website and redis is its storage. I first
>>>>> run them on host A
>>>>> >
>>>>> > I try to checkpoint them and copy to another host(host B). I create
>>>>> two containers with same configuration
>>>>> > of them and applied the change of file system to the new created
>>>>> container. Then I tried to restore them,
>>>>> > which sometimes came out a wrong result.
>>>>> > I notice that when redis and app have same ip address on host A and
>>>>> B, then the restore will success. But,
>>>>> > when they have different IP on two hosts, the restore progress will
>>>>> certainly broken.
>>>>> >
>>>>> > The reason I guess is that the state of tcp connection in checkpoint
>>>>> image didn't match the new environment
>>>>> > in host B. For example, redis in host A is 17.172.20.1 and app in
>>>>> host A is 17.172.20.2, then for app there
>>>>> > is a connection whose remote host is 17.172.20.1. Then come to host
>>>>> B, if redis in host B is 17.172.20.3 and
>>>>> > when I try to restore app, criu will confuse where is
>>>>> 17.172.20.1(redis)?
>>>>>
>>>>> After migration all the sockets get restored with the IP addresses
>>>>> they had on source node,
>>>>> so if for some reason packets to former container IP cannot be
>>>>> delivered into container's
>>>>> new location, the container would get broken. This is unavoidable
>>>>> limitation of TCP protocol
>>>>> itself. There can be workarounds to this (DNAT-like for example), but
>>>>> this is out of CRIU's
>>>>> scope and should be done on Docker level.
>>>>>
>>>>> > Generally, is there always a problem to checkpoint and restore a
>>>>> container, who has a link with other
>>>>> > containers, on the another host?
>>>>> >
>>>>> > And who knows that how to use a specific IP address while start a
>>>>> new container? For the latest release of
>>>>> > cr-combined doesn't support docker run --ip. Even --ip is supported,
>>>>> it requires a user defined network,
>>>>> > default network is not supported.
>>>>> >
>>>>> > Hopes for your kindly response & wish all of you a great day!
>>>>> >
>>>>> > Regards,
>>>>> >
>>>>> > David Sun
>>>>> >
>>>>> >
>>>>> >
>>>>> > _______________________________________________
>>>>> > CRIU mailing list
>>>>> > CRIU at openvz.org
>>>>> > https://lists.openvz.org/mailman/listinfo/criu
>>>>> >
>>>>>
>>>>>
>>>>
>
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