fabric8/java-jboss-openjdk8-jdk
Fabric8 Java Base Image (JBoss, OpenJDK 8)
100K+
** This image is deprecated and not maintained anymore. Please select one of the other flavors (alpine, centos).**
This image is based on JBoss with OpenJDK and provides OpenJDK 8 (JDK)
It includes:
An Agent Bond agent with Jolokia and Prometheus' jmx_exporter. The agent is installed as /opt/agent-bond/agent-bond.jar
. See below for configuration options.
A startup script /deployments/run-java.sh
for starting up Java applications.
In order to enable Jolokia for your application you should use this image as a base image (via FROM
) and use the output of agent-bond-opts
in your startup scripts to include it in for the Java startup options.
For example, the following snippet can be added to a script starting up your Java application
# ...
export JAVA_OPTIONS="$JAVA_OPTIONS $(agent-bond-opts)"
# .... use JAVA_OPTIONS when starting your app, e.g. as Tomcat does
The following versions and defaults are used:
You can influence the behaviour of agent-bond-opts
by setting various environment variables:
Agent bond itself can be influenced with the following environment variables:
jolokia
and jmx_exporter
.
By default both are enabled.Jolokia configuration
/opt/jolokia/jolokia.properties
.0.0.0.0
)8778
)serverCert
configuration is given in AB_JOLOKIA_OPTS
$HOSTNAME
by default, which is the container id)Some options for integration in various environments:
/var/run/secrets/kubernetes.io/serviceaccount/ca.crt
jmx_exporter configuration
jmx_exporter
(in the format <port>:<path to config>
)9779
jmx_exporter
: Default: /opt/agent-bond/jmx_exporter_config.json
The default command for this image is /deployments/run-java.sh. Its purpose it to fire up Java applications which are provided as fat-jars, including all dependencies or more classical from a main class, where the classpath is build up from all jars within a directory.
For these images the variable JAVA_APP_DIR has the default value /deployments
This general purpose startup script is optimized for running Java application from within containers. It is called like
./run-java.sh <sub-command> <options>
run-java.sh
knows two sub-commands:
options
to print out JVM option which can be used for own invocation of Java apps (like Maven or Tomcat). It respects container constraints and includes all magic which is used by this scriptrun
executes a Java application as described below. This is also the default command so you can skip adding this command.When no subcommand is given (or when you provide the default subcommand run
), then by default this scripts starts up Java application.
The startup process is configured mostly via environment variables:
classpath
file which holds the classpath. Either as a single line classpath (colon separated) or with jar files listed line-by-line. If not set JAVA_LIB_DIR is the same as JAVA_APP_DIR.java
JAVA_VERSION
variable, the release
file or parsing the java -version
command output.-Xmx
option is given in JAVA_OPTIONS
. This is used to calculate a default maximal Heap Memory based on a containers restriction. If used in a Docker container without any memory constraints for the container then this option has no effect. If there is a memory constraint then -Xmx
is set to a ratio of the container available memory as set here. The default is 25
when the maximum amount of memory available to the container is below 300M, 50
otherwise, which means in that case that 50% of the available memory is used as an upper boundary. You can skip this mechanism by setting this value to 0 in which case no -Xmx
option is added.-Xms
option is given in JAVA_OPTIONS
. This is used to calculate a default initial Heap Memory based on a containers restriction. If used in a Docker container without any memory constraints for the container then this option has no effect. If there is a memory constraint then -Xms
is set to a ratio of the container available memory as set here. By default this value is not set.java
. When this environment variable is given, all jar files in $JAVA_APP_DIR
are added to the classpath as well as $JAVA_LIB_DIR
.java -jar
if no $JAVA_MAIN_CLASS
is set. In all cases this jar file is added to the classpath, too.${JAVA_APP_DIR}/classpath
and use its content literally as classpath. If this file doesn't exists all jars in the app dir are added (classes:${JAVA_APP_DIR}/*
).http.proxyHost
and http.proxyPort
system properties.https.proxyHost
and https.proxyPort
system properties.http.nonProxyHosts
system property.If neither $JAVA_APP_JAR
nor $JAVA_MAIN_CLASS
is given, $JAVA_APP_DIR
is checked for a single JAR file which is taken as $JAVA_APP_JAR
. If no or more then one jar file is found, an error is thrown.
The classpath is build up with the following parts:
$JAVA_CLASSPATH
is set, this classpath is taken.$JAVA_APP_DIR
, $JAVA_APP_DIR
is added.$JAVA_MAIN_CLASS
is set, then
$JAVA_APP_JAR
is added if set$JAVA_APP_DIR/classpath
exists, its content is appended to the classpath. This file
can be either a single line with the jar files colon separated or a multi-line file where each line
holds the path of the jar file relative to $JAVA_LIB_DIR
(which by default is the $JAVA_APP_DIR
)${JAVA_APP_DIR}/*
is added which effectively adds all
jars in this directory in alphabetical order.These variables can be also set in a shell config file run-env.sh
, which will be sourced by the startup script. This file can be located in the directory where the startup script is located and in ${JAVA_APP_DIR}
, whereas environment variables in the latter override the ones in run-env.sh
from the script directory.
This startup script also checks for a command run-java-options
. If existent it will be called and the output is added to the environment variable $JAVA_OPTIONS
.
The startup script also exposes some environment variables describing container limits which can be used by applications:
Any arguments given to the script are given through directly as argument to the Java application.
Example:
# Set the application directory directly
export JAVA_APP_DIR=/deployments
# Set -Xmx based on container constraints
export JAVA_MAX_MEM_RATIO=40
# Start the jar in JAVA_APP_DIR with the given arguments
./run-java.sh --user maxmorlock --password secret
This script can also be used to calculate reasonable, best-practice options for starting Java apps in general. For example, when running Maven in a container it makes sense to respect container Memory constraints.
The subcommand options
can be used to print options to standard output so that is can be easily used to feed it to another, Java based application.
When no extra arguments are given, all defaults will be used, which can be influenced with the environment variables described above.
You can select specific sets of options by providing additional arguments:
--debug
: Java debug options if JAVA_DEBUG
is set--memory
: Memory settings based on the environment variables given--proxy
: Evaluate proxy environments variables--cpu
: Tuning when the number of cores is limited--gc
: GC tuning parameters--jit
: JIT options--diagnostics
: Print diagnostics options when JAVA_DIAGNOSTICS
is set--java-default
: Same as --memory --jit --diagnostic --cpu --gc
Example:
# Call Maven with the proper memory settings when running in an container
export MAVEN_OPTS="$(run-java.sh options --memory)"
mvn clean install
docker pull fabric8/java-jboss-openjdk8-jdk