Dockerfile.k8s

# syntax=docker/dockerfile:1.3-labs

FROM example-spring-boot-checkpoint
RUN apt-get update && apt-get install -y ncat
ENV CRAC_FILES_DIR=/cr

# This script is going to be used in the checkpointing job
COPY <<'EOF' /checkpoint.sh
#!/bin/sh

mkdir -p $CRAC_FILES_DIR
rm $CRAC_FILES_DIR/* || true

# After receiving connection on port 1111 trigger the checkpoint (using numeric address to avoid IPv6 problems)
(nc -v -l -p 1111 && jcmd example-spring-boot.jar JDK.checkpoint) &
# we cannot exec java ... because the pod would be marked as failed when it exits
# with exit code 137 after checkpoint
java -XX:CRaCCheckpointTo=$CRAC_FILES_DIR -XX:CRaCMinPid=128 -jar /example-spring-boot.jar &
PID=$!
trap "kill $PID" SIGINT SIGTERM
wait $PID || true
EOF

COPY <<'EOF' /restore-or-start.sh
#!/bin/sh

if [ -z "$(ls -A $CRAC_FILES_DIR 2> /dev/null)" ]; then
  echo "No checkpoint found, starting the application normally..."
  exec java -jar /example-spring-boot.jar
else
  echo "Checkpoint is present, restoring the application..."
  exec java -XX:CRaCRestoreFrom=$CRAC_FILES_DIR
fi
EOF

ENTRYPOINT [ "bash" ]
CMD [ "/restore-or-start.sh" ]