Not able to access HDFS, getting Connection exception.

[#1]

I started the Cloudera VM normally, But when I am doing a list on the files in HDFS, I am getting a Connection Exception as follows:

[cloudera@quickstart ~]$ hadoop fs -ls /user/
ls: Call From quickstart.cloudera/127.0.0.1 to quickstart.cloudera:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused

I guess it is because of the Hadoop services not running but can somebody please suggest, when i am starting the CLoudera VM as required why getting this error?

[#2]

I have the same problem, tail command is getting this output:

2015-08-06 07:47:26,459 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Problem connecting to server: 0.0.0.0/0.0.0.0:8022
2015-08-06 07:47:32,462 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:8022. Already tried 0 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-08-06 07:47:33,463 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:8022. Already tried 1 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-08-06 07:47:34,464 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:8022. Already tried 2 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-08-06 07:47:35,465 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:8022. Already tried 3 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-08-06 07:47:36,466 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:8022. Already tried 4 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-08-06 07:47:37,467 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:8022. Already tried 5 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-08-06 07:47:38,468 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:8022. Already tried 6 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-08-06 07:47:39,469 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:8022. Already tried 7 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-08-06 07:47:40,471 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:8022. Already tried 8 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-08-06 07:47:41,472 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: 0.0.0.0/0.0.0.0:8022. Already tried 9 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-08-06 07:47:41,473 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Problem connecting to server: 0.0.0.0/0.0.0.0:8022

Before i notice this problem i updated the centos image doing sudo yum update, 3GB of new data...

Is there any way to see whats going on with a graphical user interface?

[#3]

You can check the status of a service with

sudo service <service-name> status

and you can restart a service with

sudo service <service-name> restart

If you run the above command without sudo, you might get error message like Error: Root User required. 

[#4]

Try hdfs dfs -ls /