My cluster: 1 master, 11 slaves, each node has 6 GB memory.
My settings:
spark.executor.memory=4g, Dspark.akka.frameSize=512
Have a look at the start up scripts a Java heap size is set there, it looks like you're not setting this before running Spark worker.
# Set SPARK_MEM if it isn't already set since we also use it for this process
SPARK_MEM=${SPARK_MEM:-512m}
export SPARK_MEM
# Set JAVA_OPTS to be able to load native libraries and to set heap size
JAVA_OPTS="$OUR_JAVA_OPTS"
JAVA_OPTS="$JAVA_OPTS -Djava.library.path=$SPARK_LIBRARY_PATH"
JAVA_OPTS="$JAVA_OPTS -Xms$SPARK_MEM -Xmx$SPARK_MEM"
You can find the documentation to deploy scripts here.