Falchion

Falchion is an antifragile JVM container. Falchion container requires JDK9 because it's using SO_REUSEPORT flag. JDK9 supports SO_REUSEPORT only on Linux.

When the container has started, it forks JVM processes until the given pool size. If the container catch a HUP signal, it creates a new JVM processes and kill old processes.

Usage

Download the falchion script and run.

% falchion [mainClass] -cp classpath

Options

• -cp Classpath
• -basedir The base directory of jar files
• -v application version
• -p The pool size of JVM processes. (default value is 1)
• --lifetime LIFETIME SECONDS The lifetime of one jvm process. If you set the option to 3600, container will kill all old JVMs and create new JVMs gracefully.
• -m MONITORS Adds monitors for monitoring a jvm process. Available monitors:
  • JSTAT_GCUTIL GC statistics using jstat
  • METRICS_JMX Metrics using JMX
• --auto-tuning tuning JVM parameters automatically.
• --evaluator EVALUATOR

When using the options "-basedir" and "-v", Falchion container generates classpath using basedir and aplVersion. Please set the folder hierarchy like the example below.

• applicationBaseDir <- basedir
  • 0.1.0 <- application version
    • applicationA.jar
    • applicationB.jar
    • subDir
      • applicationC.jar
  • 0.1.1

REST API

Falchion container provides HTTP APIs for getting the information of JVM processes or refreshing JVM processes.

GET /jvms

% curl -i http://localhost:44010/jvms
HTTP/1.1 200 OK
Date: Mon, 02 May 2016 10:11:24 GMT
Content-type: application/json
Content-length: 28

[{"id":"5jiic","pid":21914}]

GET /jvm/{id}

% curl -i http://localhost:44010/jvm/5jiic
HTTP/1.1 200 OK
Date: Mon, 02 May 2016 10:12:23 GMT
Content-type: application/json
Content-length: 182

{"id":"5jiic","pid":21914,"uptime":258357,"stats":[{"type":"gcutil","S0":0.0,"S1":100.0,"E":16.88,"O":3.1,"M":94.86,"CCS":80.13,"YGC":1,"YGCT":0.004,"FGC":0,"FGCT":0.0,"GCT":0.004}]}

POST /container/refresh

Kill all old JVMs and create new JVMs gracefully.

POST /container/refresh/{version}

Kill all old JVMs and create new JVMs gracefully. Change classpath using new version.

Auto tuning

Falchion can optimize JVM options automatically.