Travis CI ignoring MAVEN_OPTS?

问题:

My Scala project (Maven-managed) is failing to build on Travis, throwing a GC overhead limit exceeded error despite compiling fine locally with the same MAVEN_OPTS=-Xmx3g -XX:MaxPermSize=512m. I suspect that Travis is somehow ignoring my MAVEN_OPTS: When I try to test against Oracle JDK 8, Travis logs:

$ Setting environment variables from .travis.yml
$ export MAVEN_OPTS="-XX:MaxPermSize=512m -Xmx3g"

which looks good. However, soon after it logs:

Java HotSpot(TM) 64-Bit Server VM warning: ignoring option MaxPermSize=192m; support was removed in 8.0

which is troubling since NOWHERE am I specifying -XX:MaxPermSize=192m, only 512m. (This leads me to believe my -Xmx3g is also being ignored, causing the compilation failure.)

I tried specifying the MAVEN_OPTS in many additional places in my pom, to no avail. For example, for the maven-scala-plugin, I have:

<configuration>
  ...
  <jvmArgs>
    <jvmArg>-Xmx3g</jvmArg>
    <jvmArg>-XX:MaxPermSize=512m</jvmArg>
  </jvmArgs>
</configuration>

And I also have the following under the maven-surefire-plugin and scalatest plugin, though the build is failing during compilation not tests:

<configuration>
  <argLine>-Xmx3g -XX:MaxPermSize=512m</argLine>
</configuration>

The following is the entirety of my .travis.yml:

language: java
env:
  global:
    - MAVEN_OPTS="-XX:MaxPermSize=512m -Xmx3g"
script: mvn clean install
jdk:
    - oraclejdk8
    - oraclejdk7

I'm using Scala 2.11.2 and scala-maven-plugin 3.2.0.

回答1:

UPDATE (11/2/15):

This was finally fully resolved here. Quoting:

If you want to use container-based builds (not relying on sudo), you can echo what you want into a $HOME/.mavenrc file and that will take precedence over /etc/mavenrc, like so:

in .travis.yml:

before_script:
  - echo "MAVEN_OPTS='-Xmx2g -XX:MaxPermSize=512m'" > ~/.mavenrc

(you could also put this in before_install depending on your setup).

Old answer:

I finally found the answer here, which references this (closed but not resolved) issue on the Travis CI github.

It seems like Travis exports a MAVEN_OPTS environment variable as root via the file /etc/mavenrc, which then does not get overridden by any other MAVEN_OPTS definitions (e.g. via env/global settings in the travis config). The workaround is to delete /etc/mavenrc before setting custom MAVEN_OPTS.

I was able to set custom MAVEN_OPTS and build successfully using the following in my .travis.yml:

script:
  - sudo rm /etc/mavenrc
  - export MAVEN_OPTS="-Xmx2469m -XX:MaxPermSize=512m"
  - mvn clean install

Note that I am NOT using language: java in my travis config, just calling maven directly via the script directive.

回答2:

export MAVEN_SKIP_RC=true is the recommended way of doing this when dealing with a system that has an /etc/mavenrc. This will make it ignore the defaults and read the MAVEN_OPTS variable.

回答3:

While it is possible to set -Xmx3g in Travis CI builds, its servers have limited memory to be free for JVM heap in forked surefire tests.

Here is project that use -Xmx2560m for max speed on Travis CI: https://github.com/plokhotnyuk/actors/blob/8f22977981e0c4d21b67beee994b339eb787ee9a/pom.xml#L151

You can check available memory by - sudo cat /proc/meminfo line added to .travis.yml. Here is output from some Travis CI build: https://travis-ci.org/plokhotnyuk/actors/jobs/55013090#L923

If your project requires bigger heap size then try https://www.shippable.com

Or it is better to use Wercker (much faster builds and without waiting in queue at all) http://wercker.com

回答4:

This is what finally worked for me.

language: java
sudo: false
jdk:
  - oraclejdk8
install: MAVEN_SKIP_RC=true MAVEN_OPTS="-Xss4M" mvn install -DskipTests=true
script: MAVEN_SKIP_RC=true MAVEN_OPTS="-Xss4M" mvn

The MAVEN_SKIP_RC is needed as @adam says and the MAVEN_OPTS are what I needed to get javac to stop blowing out the stack.