How to pass System property to docker containers?

Question

So I know you can pass Environment variables to a docker container using -e like:

docker run -it -e "var=var1" myDockerImage

But I need to pass a System Property to a docker container, because this is how I run my JAR:

java -Denvironment=dev -jar myjar.jar 

So how can I pass a -D System property in Docker? Like:

docker run -it {INSERT Denvironment here} myDockerImage

Answer 1

Use the variable you passed into the container on the java command:

docker run -it -e "ENV=dev" myDockerImage
java -Denvironment=$ENV -jar myjar.jar

Answer 2

One more way to do it, if running under Tomcat, is setting your system variables in your Dockerfile using ENV JAVA_OPTS like this:

ENV JAVA_OPTS="-Djavax.net.ssl.trustStore=C:/tomcatDev.jks -D_WS_URL=http://some/url/"

Hope it helps!