jvmctl

jvmctl is a tool for deploying and managing Java applications on EL7 servers. It wraps systemd, git, jstack and other tools to provide a friendly command-line interface to common deployment, process management and debugging tasks.

Installation

Install Python 2.7 (you probably already have it)
cd jvmctl && python setup.py install

Depending on the applications you want to run you may also want to install a JDK, version control (git, svn) and build tools (Maven, Gradle).

Configuration

Application configuration files look like:

REPO=svn://svn.example.org/myapp/trunk
PORT=1234
HEAP_SIZE=512m

Basic shell-style $VARIABLE substition is supported:

JAVA_OPTS=-Dmyapp.port=$PORT

For backwards compatibility reasons lines can be prefixed with "export " (this has no effect). All options are passed to the deployment script and application as environment variables.

Deployment Options

Option	Default	Description
REPO		svn or git repository url to deploy from
GIT_BRANCH	master	git branch to deploy from

Process Options

Option	Default	Description
USER	webapp	unix account to run the application under
JAVA_HOME	/usr/lib/jvm/java-1.8.0	path of the Java runtime to use
JAVA_OPTS		extra options to pass to java (system properties, GC options etc)
HEAP_DUMP_PATH	/var/tmp/${NODE}.hprof	file or directory to store heap dumps
HEAP_SIZE	128m	amount of memory allocated to the jvm
OOM_EMAIL	root@localhost	address to email out of memory errors to
EXEC_PREFIX		prefix to append to the executed command-line (use for wrapper scripts)

Webapp Options

Option	Default	Description
CONTAINER	jetty	Servlet container to use or `none`
JETTY_VERSION	9.2.5.v20141112	Version of jetty to use (will be downloaded automatically)
PORT		HTTP port for servlet container
ROOT_URL_PREFIX	/	path to mount web application under
NLA_ENVIRON	devel	(deprecated) application environment profile
WEBAPPS_PATH	/apps/$node	Directory to search for webapps and war files

FAQ

Where did my logs go??

jvmctl delegates log handling to the systemd journald. Logs are stored in an annotated binary format in /var/log/jornal and can be viewed, tailed and searched using journalctl:

sudo jvmctl myapp log
sudo journalctl -u jvm:myapp -f
sudo journalctl -u jvm:myapp -n 100

See man journalctl for more options. You can also configure journald to forward logs to syslog to write to text files or a remote logserver. See man journald.conf.

Why Python 2 and not Python 3/Perl/Ruby/Java/bash/...?

It's installed by default on most servers, starts fast and has a large standard library with good error handling and APIs for interacting with OS services. And I know it much better than Perl. ;-)

How about other OSes?

jvmctl delegates to systemd for process and log management to systemd. While it would be possible to add support for other systems (and indeed our previous generation tool did) standardising on one platform has made the code considerably simpler. In future we may consider adding Solaris support again as SMF also provides much of the required functionality.

nla / jvmctl

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