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| − | == What CRtools is ==
| + | See main article here [http://criu.org/CR_tools] |
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| − | '''CRtools''' is an utility to checkpoint/restore process tree. Unlike checkpoint/restore implemented completely in kernel space,
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| − | it tries to achieve the same target mostly in user space.
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| − | === Agenda ===
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| − | # Basic design (checkpoint == proc + SEIZE, restore == syscalls + execve)
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| − | # What's required from kernel
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| − | == Basic design ==
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| − | === Checkpoint ===
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| − | The checkpoint procedure relies heavily on '''/proc''' file system (it's a general place where crtools takes all the information it needs).
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| − | Which includes:
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| − | * Files descriptors information (via '''/proc/$pid/fd''' and '''/proc/$pid/fdinfo''')
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| − | * Pipes parameters
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| − | * Memory maps (via '''/proc/$pid/maps''')
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| − | The process dumper (lets call it simply the dumper further) does the following steps during checkpoint stage:
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| − | # A '''$pid''' of a process group leader is obtained from the command line
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| − | # By using this '''$pid''' the dumper walks though '''/proc/$pid/status''' and gathers children '''$pids''' recursively. At the end we will have a process tree.
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| − | # Then it takes every '''$pid''' from a process tree, sends ''SIGSTOP'' to every process found, and performs the following steps on each '''$pid'''
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| − | #* Collects VMA areas by parsing '''/proc/$pid/maps'''
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| − | #*
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Latest revision as of 20:31, 17 December 2011
See main article here [1]
