HA HDFS on Apache Mesos

Starts 1 active NameNode (with JournalNode and ZKFC), 1 standby NN (+JN,ZKFC), 1 JN, and everything else is DataNodes.

Building HDFS-Mesos

1. ./bin/build-hdfs
2. Run ./bin/build-hdfs nocompile to skip the mvn clean package step and just re-bundle the binaries.
3. To remove the project build output and downloaded binaries, run ./bin/build-hdfs clean

Installing HDFS-Mesos on your Cluster

1. Upload hdfs-mesos-*.tgz to a node in your Mesos cluster.
2. Extract it with tar zxvf hdfs-mesos-*.tgz
3. Customize configuration in hdfs-mesos-*/etc/hadoop/*-site.xml
4. Check that hostname on that node resolves to a non-localhost IP; update /etc/hosts if necessary

Starting HDFS-Mesos

1. cd hdfs-mesos-*
2. ./bin/hdfs-mesos
3. Check the Mesos web console to wait until all tasks are RUNNING (monitor status in JN sandboxes)

Using HDFS

See some of the many HDFS tutorials out there for more details and explore the web UI at
http://<ActiveNameNode>:50070.
Also here is a quick sanity check:

1. hadoop fs -ls hdfs://<ActiveNameNode>:50071/ should show nothing for starters
2. hadoop fs -put /path/to/src_file hdfs://<ActiveNameNode>:50071/
3. hadoop fs -ls hdfs://<ActiveNameNode>:50071/ should now list src_file

Resource Reservation Instructions (Optional)

1. In mesos-site.xml, change mesos.hdfs.role to hdfs.
2. On master, add the role for HDFS, by running echo hdfs > /etc/mesos-master/role or by setting the —-role=hdfs.
3. Then restart the master by running sudo service mesos-master restart.
4. On each slave where you want to reserve resources, add specific resource reservations for the HDFS role. Here is one example:
   cpus(*):4;cpus(hdfs):2;mem(*):8192;mem(hdfs):4096 > /etc/mesos-slave/resources
   or by setting —-resources=cpus(*):4;cpus(hdfs):2;mem(*):8192;mem(hdfs):4096.
5. On each slave with the new settings, stop the mesos slave by running
   sudo service mesos-slave stop
   .
6. On each slave with the new settings, remove the old slave state by running
   rm -f /tmp/mesos/meta/slaves/latest
   .
   Note: This will also remove task state, so you will want to manually kill any running tasks as a precaution.
   
7. On each slave with the new settings, start the mesos slave by running
   sudo service mesos-slave start
   .