Proposed F19 Feature: Checkpoint/Restore

[Josh Boyer]

On Thu, Jan 24, 2013 at 10:58 AM, Adrian Reber <adrian at lisas.de> wrote:
> On Wed, Jan 23, 2013 at 03:37:46PM -0500, Josh Boyer wrote:
>> On Wed, Jan 23, 2013 at 2:35 PM, Jaroslav Reznik <jreznik at redhat.com> wrote:
>> > To offer the checkpoint/restore functionality the package crtools has been
>> > imported into Fedora and changes are still necessary to the kernel RPM.
>>
>> The CRIU page doesn't say you need CONFIG_NAMESPACES enabled to use CRIU.
>> Also, there is nothing in the kernel Kconfig dependencies that would
>> select or require that set to turn on CONFIG_CHECKPOINT_RESTORE.  Could
>> you be more explicit as to why you need namespaces turned on?
>
> CONFIG_NAMESPACES took me some time to find out. I actually need
> CONFIG_CHECKPOINT_RESTORE which requires CONFIG_EXPERT. I also need (for
> restore) CONFIG_PID_NS which is enabled in config-generic

Why does restore need PID_NS?  The kernel doesn't think it does, so is
this a requirement based on the userspace tooling?

> config-generic:CONFIG_PID_NS=y
>
> Looking at the config of a built kernel I see that it is not enabled.
> Looking at init/Kconfig I see that CONFIG_PID_NS is only enabled if
> CONFIG_NAMESPACES is enabled.

Right.

> CONFIG_NAMESPACES seems to be required to make all those activated _NS
> options actually enabled:
>
> config-generic:CONFIG_PID_NS=y
> config-generic:CONFIG_UTS_NS=y
> config-generic:CONFIG_IPC_NS=y
> config-generic:CONFIG_NET_NS=y

Those might be doable.  I take it you very clearly don't need USER_NS,
right?  Because that option is not going to be enabled at the expense of
the things I listed.

josh