Messages in this thread | | | Date | Wed, 3 Sep 2008 09:18:41 -0500 | From | "Serge E. Hallyn" <> | Subject | Re: [PATCH 0/9] OpenVZ kernel based checkpointing/restart |
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Quoting Cedric Le Goater (clg@fr.ibm.com): > Andrey Mirkin wrote: > > This patchset introduces kernel based checkpointing/restart as it is > > implemented in OpenVZ project. This patchset has limited functionality and > > are able to checkpoint/restart only single process. Recently Oren Laaden > > sent another kernel based implementation of checkpoint/restart. The main > > differences between this patchset and Oren's patchset are: > > > > * In this patchset checkpointing initiated not from the process > > (right now we do not have a container, only namespaces), Oren's patchset > > performs checkpointing from the process context. > > > > * Restart in this patchset is initiated from process, which restarts a new > > process (in new namespaces) with saved state. Oren's patchset uses the same > > process from which restart was initiated and restore saved state over it. > > > > * Checkpoint/restart functionality in this patchset is implemented as a kernel > > module > > why ? Do we really think that C/R implementations will be so different that > we will need C/R ops to support all of them ? I imagine that there could be > different models :
At the mini-summit two reasons were brought up to make it a module:
1. So sysadmins worried about security implications can completely unload the module
2. So developers can unload and reload the module while testing.
> 1. brute force : dump it all and kill > 2. incremental > 3. live migration > ...
Actually I don't think we expected to use different implementations for those.
> But I see all of them really tied to the kernel internals. > > The first issues I see with this direction are some EXPORT_SYMBOL() that would > be useless without a module. > > > As checkpointing is initiated not from the process which state should be saved > > we should freeze a process before saving its state. Right now Container Freezer > > from Matt Helsley can be used for this. > > OK that's integrated and Daniel's tools : > > http://lxc.cvs.sourceforge.net/lxc/ > > one more reason to work on integration :) > > C. > > > > This patchset introduce only a concept how kernel based checkpointing/restart > > can be implemented and are able to checkpoint/restart only a single process > > with simple VMAs. > > > > I've tried to split my patchset in small patches to make review more easier. > > _______________________________________________ > > Containers mailing list > > Containers@lists.linux-foundation.org > > https://lists.linux-foundation.org/mailman/listinfo/containers > > > > _______________________________________________ > Containers mailing list > Containers@lists.linux-foundation.org > https://lists.linux-foundation.org/mailman/listinfo/containers
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