What if your Hadoop application get stuck

In a multiple application environment (MapReduce, Tez, others), it can appear that some application get stuck (blocked, deadlocked), it is likely your YARN / MAPREDUCE settings need to be reviewed. First of all, setup YARN queue, check the value of mapreduce.job.reduce.slowstart.completedmaps (interesting to change it to 0.9) and enable preemption.