In fact, in MVP, 'status' won't be called for nested containers.
Containerizer will enforce that.

On Fri, Sep 16, 2016 at 9:01 PM, Avinash Sridharan <avin...@mesosphere.io>
wrote:

>
>
> On Fri, Sep 16, 2016 at 8:53 PM, Jie Yu <yujie....@gmail.com> wrote:
>
>> containers should be able to operate even if the parent container goes
>>> away
>>
>>
>> This should never happen. One of the nesting feature is: if the parent
>> container goes way, all its child containers will go away too. The
>> containerizer will enforce it.
>>
>> Reason being that during recovery the containers need to be re-populated
>>> in the `infos` structure. Otherwise there would be descripancy between the
>>> containers present in `infos` before and after recovery.
>>
>>
>> Ok, in that case its my bad. I misunderstood, thinking that in future the
> kill policy might allow reincarnation of the parents without killing the
> children. So using the parents network files directly should just work.
>
>> We already have that discrepancy. If a container joining the host network
>> has a rootfs, we'll construct an Info, but we will not recover it. I think
>> we just need to follow the same.
>>
>> In retrospect, we probably should not create 'Info' for that case, we
>> probably should use a different map. We can clean that up later.
>>
>> Ok, for MVP, I will keep the current behavior (with the discrepancy).
> Won't create a containerDir for this child containers. Will need to
> implement some extra checks in `status` to get correct `ContainerStatus`
> for containers not in `infos`, but that should be trivial.
>
>> - Jie
>>
>> On Fri, Sep 16, 2016 at 8:01 PM, Avinash sridharan <avin...@mesosphere.io
>> > wrote:
>>
>>>
>>>
>>> > On Sept. 17, 2016, 1 a.m., Jie Yu wrote:
>>> > > src/slave/containerizer/mesos/isolators/network/cni/cni.cpp, lines
>>> 816-820
>>> > > <https://reviews.apache.org/r/51871/diff/5/?file=1500794#fil
>>> e1500794line816>
>>> > >
>>> > >     Any reason we need to copy the network files, instead of just
>>> using it? Do we really need to have a containerDir for nested container? I
>>> like the invariant that we only have a containerDir if we actually create
>>> network for the container.
>>>
>>> That is a good point. The only reason I was thinking about maintaining a
>>> copy of each of the network files is that the containers should be able to
>>> operate even if the parent container goes away. This is not an issue for
>>> the MVP, but I was thinking this might be an issue later on when we have
>>> different kill policies enforced.
>>>
>>> That said, after seeing you comment, I am realizing that just copying
>>> the network files is not enough, we need to copy the entire parentDir if we
>>> want to maintain the container operation in the abscene of the parent
>>> container. Which gets complicated. So if we shouldn't worry too much about
>>> this case, then I agree we can just do without using the parent files, and
>>> keep it much simpler.
>>>
>>> Irrespective of whether we use parent's network files, or copy over the
>>> files, I think we still need a `containerDir` for each container. Reason
>>> being that during recovery the containers need to be re-populated in the
>>> `infos` structure. Otherwise there would be descripancy between the
>>> containers present in `infos` before and after recovery. This, I think,
>>> would convolute the logic we would have in `status`, which is critical to
>>> retrieve the container's IP address.
>>>
>>>
>>> - Avinash
>>>
>>>
>>> -----------------------------------------------------------
>>> This is an automatically generated e-mail. To reply, visit:
>>> https://reviews.apache.org/r/51871/#review149310
>>> -----------------------------------------------------------
>>>
>>>
>>> On Sept. 16, 2016, 11:31 p.m., Avinash sridharan wrote:
>>> >
>>> > -----------------------------------------------------------
>>> > This is an automatically generated e-mail. To reply, visit:
>>> > https://reviews.apache.org/r/51871/
>>> > -----------------------------------------------------------
>>> >
>>> > (Updated Sept. 16, 2016, 11:31 p.m.)
>>> >
>>> >
>>> > Review request for mesos, Gilbert Song, Jie Yu, Joseph Wu, and Qian
>>> Zhang.
>>> >
>>> >
>>> > Bugs: MESOS-6156
>>> >     https://issues.apache.org/jira/browse/MESOS-6156
>>> >
>>> >
>>> > Repository: mesos
>>> >
>>> >
>>> > Description
>>> > -------
>>> >
>>> > The network file setup in the `network/cni` isolator is now nesting
>>> > aware. Since the children share the network and UTS namespace with the
>>> > parent, the network files need to be created only for the parent
>>> > container. For the child containers, the network files will be simply
>>> > a symlink to a parents network files.
>>> >
>>> >
>>> > Diffs
>>> > -----
>>> >
>>> >   src/slave/containerizer/mesos/isolators/network/cni/cni.cpp
>>> 822f11eab5b00c014563322a8c3b2c14cb440e0b
>>> >
>>> > Diff: https://reviews.apache.org/r/51871/diff/
>>> >
>>> >
>>> > Testing
>>> > -------
>>> >
>>> > make
>>> > make check
>>> > sudo ./bin/mesos-tests.sh
>>> >
>>> >
>>> > Thanks,
>>> >
>>> > Avinash sridharan
>>> >
>>> >
>>>
>>>
>>
>
>
> --
> Avinash Sridharan, Mesosphere
> +1 (323) 702 5245
>

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