Difference between revisions of "Applying images"
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(Created page with "The page describes thoughts about how to take an existing process and apply images into it, instead of turn CRIU process into target one.") |
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The page describes thoughts about how to take an existing process and apply images into it, instead of turn CRIU process into target one. | The page describes thoughts about how to take an existing process and apply images into it, instead of turn CRIU process into target one. | ||
+ | |||
+ | == What for == | ||
+ | |||
+ | This feature is useful for | ||
+ | |||
+ | ;Reverting to snapshot | ||
+ | :In case process keep running after a snapshot, reverting back might be faster if not restoring from images, but applying those directly on the running tasks | ||
+ | |||
+ | ;FT case | ||
+ | :In fault tolerant systems master node would send updates to slave one(s) and the latter guys would benefit from ability to "add" the snapshot update onto existing tasks | ||
+ | |||
+ | == Problem == | ||
+ | |||
+ | There's a technical problem in it -- currently CRIU restores data from images into itself. Only a small portion of code is executed in a PIE mode (called "[[restorer context]]") and that is run in a target task environment. In apply-images mode we'd have to push parasite into target task and run ''all'' the restoration code in it. This is a lot of patching. | ||
+ | |||
+ | [[Category:Plans]] |
Latest revision as of 14:55, 27 January 2015
The page describes thoughts about how to take an existing process and apply images into it, instead of turn CRIU process into target one.
What for[edit]
This feature is useful for
- Reverting to snapshot
- In case process keep running after a snapshot, reverting back might be faster if not restoring from images, but applying those directly on the running tasks
- FT case
- In fault tolerant systems master node would send updates to slave one(s) and the latter guys would benefit from ability to "add" the snapshot update onto existing tasks
Problem[edit]
There's a technical problem in it -- currently CRIU restores data from images into itself. Only a small portion of code is executed in a PIE mode (called "restorer context") and that is run in a target task environment. In apply-images mode we'd have to push parasite into target task and run all the restoration code in it. This is a lot of patching.