How to check if Hadoop daemons are running?

Question

What are simple commands to check if Hadoop daemons are running?

For example if I\'m trying to figure out why HDFS is not setup correctly I\'ll want to know a way to ch

Answer 1

To check whether Hadoop Nodes are running or not:

sudo -u hdfs hdfs dfsadmin -report

Configured Capacity: 28799380685 (26.82 GB)
Present Capacity: 25104842752 (23.38 GB)
DFS Remaining: 25012056064 (23.29 GB)
DFS Used: 92786688 (88.49 MB)
DFS Used%: 0.37%
Under replicated blocks: 436
Blocks with corrupt replicas: 0
Missing blocks: 0

---

Datanodes available: 1 (1 total, 0 dead)

Live datanodes:
Name: 127.0.0.1:50010 (localhost.localdomain)
Hostname: localhost.localdomain
Rack: /default
Decommission Status : Normal
Configured Capacity: 28799380685 (26.82 GB)
DFS Used: 92786688 (88.49 MB)
Non DFS Used: 3694537933 (3.44 GB)
DFS Remaining: 25012056064 (23.29 GB)
DFS Used%: 0.32%
DFS Remaining%: 86.85%
Last contact: Thu Mar 01 22:01:38 IST 2018