Move ENV HADOOP_CLIENT_OPTS to end, document override

Author: hegyibalint

Dockerfile

@@ -5,8 +5,6 @@ WORKDIR /opt
 RUN apk add bash curl maven python
 RUN curl -L 'http://archive.apache.org/dist/hadoop/core/hadoop-2.6.0/hadoop-2.6.0.tar.gz' | tar -xz
 
-ENV HADOOP_CLIENT_OPTS '-Xmx8G'
-
 # Copy the project
 COPY . /opt/ldbc_snb_datagen
 WORKDIR /opt/ldbc_snb_datagen
@@ -15,4 +13,5 @@ RUN rm params*.ini
 # Build jar bundle
 RUN mvn -DskipTests clean assembly:assembly
 
+ENV HADOOP_CLIENT_OPTS '-Xmx8G'
 CMD /opt/ldbc_snb_datagen/docker_run.sh

README.md

@@ -57,6 +57,8 @@ mkdir datagen_output
 docker run --rm --mount type=bind,source="$(pwd)/datagen_output/",target="/opt/ldbc_snb_datagen/social_network/" --mount type=bind,source="$(pwd)/params.ini",target="/opt/ldbc_snb_datagen/params.ini" ldbc/datagen
 ```
 
+If the memory limit has to be raised, the `-e HADOOP_CLIENT_OPTS="-Xmx..."` parameter can override the default `-Xmx8G` value.
+
 <!-- Publicly available datasets can be found at the LDBC-SNB Amazon Bucket. These datasets are the official SNB datasets and were  generated using version 0.2.6. They are available in the three official supported serializers: CSV, CSVMergeForeign and TTL. The bucket is configured in "Requester Pays" mode, thus in order to access them you need a properly set up AWS client.
 * http://ldbc-snb.s3.amazonaws.com/ -->