Features/Checkpoint Restore

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== How To Test ==
 
== How To Test ==
<!-- This does not need to be a full-fledged document.  Describe the dimensions of tests that this feature is expected to pass when it is done.  If it needs to be tested with different hardware or software configurations, indicate them.  The more specific you can be, the better the community testing can be.
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A process should be able to be dumped with following command:
  
Remember that you are writing this how to for interested testers to use to check out your feature - documenting what you do for testing is OK, but it's much better to document what *I* can do to test your feature.
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<pre>crtools dump -D <destination-directory> -t <PID></pre>
  
A good "how to test" should answer these four questions:
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and restored with following command:
  
0. What special hardware / data / etc. is needed (if any)?
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<pre>crtools restore -D <destination-directory> -t <PID></pre>
1. How do I prepare my system to test this feature? What packages
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need to be installed, config files edited, etc.?
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2. What specific actions do I perform to check that the feature is
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working like it's supposed to?
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3. What are the expected results of those actions?
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== User Experience ==
 
== User Experience ==

Revision as of 12:31, 24 October 2012

= Checkpoint/Restore

Contents

Summary

Add support to checkpoint and restore processes. Checkpointing processes can be used for fault tolerance and/or load balancing.

Checkpointing a process in regular intervals can help to restart a process if it might crash to resume/restart/restore the calculation without too much data lost. Providing this ability transparent at the OS level removes the need to implement this functionality for all processes manually.

Checkpointing and restoring a process to another system can be used to migrate a process, process tree or container to another system to distribute the load during the runtime and also for maintenance without service interruption like it is possible with virtual machines.

Owner

  • Email: <adrian@lisas.de>

Current status

  • Targeted release: Fedora 19
  • Last updated: 2012-10-24
  • Percentage of completion: 0%

Detailed Description

Checkpointing/restore, as mentioned above, can be used for fault tolerance and load distribution.

Fedora can offer checkpoint/restore by using CRIU (Checkpoint/Restore In Userspace). CRIU has been developed with the goal to be accepted by upstream and most patches necessary have already been accepted (as of 2012-10-24) in the kernel. The current release (0.2) of the userspace tools (crtools) offers the ability to checkpoint/restore containers and thus offering the ability to migrate containers.

To offer the checkpoint/restore functionality the package crtools has to be imported into Fedora and following changes are necessary to the kernel RPM:

diff --git a/config-x86_64-generic b/config-x86_64-generic
index 342b862..c5f8cf9 100644
--- a/config-x86_64-generic
+++ b/config-x86_64-generic
@@ -1,5 +1,8 @@
 CONFIG_64BIT=y
 
+CONFIG_EXPERT=y
+CONFIG_CHECKPOINT_RESTORE=y
+CONFIG_NAMESPACES=y
 # CONFIG_X86_X32 is not set
 # CONFIG_MK8 is not set
 # CONFIG_MPSC is not set

Benefit to Fedora

Fedora offers possibility to checkpoint/restore processes.

Scope

  • add the crtools package to Fedora
  • activate the three kernel options mentioned above (CONFIG_EXPERT, CONFIG_NAMESPACES, CONFIG_CHECKPOINT_RESTORE)

How To Test

A process should be able to be dumped with following command:

crtools dump -D <destination-directory> -t <PID>

and restored with following command:

crtools restore -D <destination-directory> -t <PID>

User Experience

Users can easily checkpoint and restore processes with the crtools package:

crtools dump -D <destination-directory> -t <PID>
crtools restore -D <destination-directory> -t <PID>

Dependencies

  • add the crtools package to Fedora
  • activate the three kernel options mentioned above (CONFIG_EXPERT, CONFIG_NAMESPACES, CONFIG_CHECKPOINT_RESTORE)

Contingency Plan

  • disable kernel options

Documentation

Users can easily checkpoint and restore processes with the crtools package:

crtools dump -D <destination-directory> -t <PID>
crtools restore -D <destination-directory> -t <PID>

http://criu.org/

Release Notes

Comments and Discussion