Just wondering whether Abmari does anything additional, when start HDFS/YARN, comparing to from command line directly.
I noted below case while testing rack awareness which prompts this questions.
- I have 4 node cluster installed by Ambari
By default, it seems Ambari has already has rack awareness enabled.
core-site.xml: <name>net.topology.script.file.name</name>core-site.xml: <value>/etc/hadoop/conf/topology_script.py</value>
topology_script.py reads config data from topology_mappings.data
topology_script.py:DATA_FILE_NAME = os.path.dirname(os.path.abspath(__file__)) + "/topology_mappings.data"
For testing purpose, I modified the rack info in topology_mappings.data
a: when restart the HDFS and YARN manually, the change takes effect
b. when restart by Ambari, the change is NOT take effect. And further, the topology_mappings.data content is over-written with 'default' value and all my change has gone. (Is Ambari collecting the rack info automatically somewhere ? )