checkpointer - primitive CRaC implementation

checkpointer provides checkpoint/restore hooks on CRIU as org.crac interface.

Requirements

• JDK 8 or later
  • Unit tests require JDK 11 or later
• Maven
• org.crac
• CRIU
  • criu package in Fedora

How to build

mvn package

How to use

See example.

You can build example with mvn package. Note that you have to run mvn package for checkpointer.

You can specify following agent option:

• addr=<address>: Listen address. localhost:10095 is set by default.
• shutdown=<true|false>: Shutdown agent thread when restre request finished. true is set by default.
• shutdown_timeout=<seconds>: Shutdown timeout for agent thread. 10 is set by default.
• gc=<true|false>: true if invoke System.gc() at beforeCheckpoint. false is set by default.

You can concatenate them with ,:

-javaagent:/path/to/checkpointer-0.1.0.jar=addr=localhost:10095,shutdown=true,shutdown_timeout=10

1. Run example app

# Build checkpointer
mvn package

# Build example
cd example/simple
mvn package

# Run example
$JAVA_HOME/bin/java -javaagent:../../target/checkpointer-0.2.0.jar -jar target/checkpointer-example-0.1.0.jar

2. Do checkpoint

mkdir /path/to/checkpoint/dir
sudo ./bin/checkpointer.sh checkpoint [PID] /path/to/checkpoint/dir

3. Restore

sudo ./bin/checkpointer.sh restore /path/to/checkpoint/dir

Under the hood

• checkpointer provides org.crac implementation especially Resource and Context. You can create your beforeCheckpoint and afterRestore hook.
• checkpointer creates HTTP endpoint to accept hook request from externals.
• criu runs with --action-script bin/checkpointer-actions.sh. checkpointer-actions.sh requests checkpointer to call hooks via REST API on checkpointer Java Agent:
  • pre-dump: beforeCheckpoint
  • post-resume: afterRestore

License

The GNU Lesser General Public License, version 3.0