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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