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connection refused - AWS (HDPCD practice exam) : getting this error eventhouth i restarted ambari-agent

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Rising Star

Hi there,

I'm trying to work with AWS for HDPCD practice exam. I ran " hdfs dfs -ls / " cmd on the terminal and getting " connection refused error". I could see all the services are not running and displays with red colour rectangle icon. I ran the below command

ssh root@namenode

password: hadoop

service ambari-agent restart

exit

~/start-all-services.sh

but, no services are running except Zookeeper and Ganglia services. Please let me know to solve this issue. Thanks! @rich

1 ACCEPTED SOLUTION

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Guru

If you startup one of our practice exams and the cluster services are not running, here are some things to try first:

1. Run the start_all_services.sh script. You can watch the progress of this script in Ambari - it uses the Ambari REST API to start all HDP services.

2. Login to Ambari and try to start services that way

3. Restart the ambari-agent process on each node in the cluster (password for root is hadoop), then run start_all_services.sh again:

ssh root@namenode "ambari-agent restart"
ssh root@resourcemanager "ambari-agent restart"   # This only applies the HDPCA exam
ssh root@hiveserver "ambari-agent restart"	# This only applies to the HDPCA exam

If none of the steps above fix the issue, then it is likely an issue with the Docker containers not starting properly. Since you do not have root access on your practice exam, the quickest solution is to simply terminate your EC2 instance and startup another one.

-Rich

View solution in original post

30 REPLIES 30

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Guru

Which Amazon region are getting the AMI from? Perhaps there is an AMI that is not working. Try starting up one in a different region and see if that works.

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New Contributor

I am using us-west-2c. Will this be a issue?

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Guru

I don't know, but try a different a region and see if you have any success.

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Explorer

my region is N virginia and public ip is ec2-54-210-61-32.compute-1.amazonaws.com

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Guru

Did you try this:

ssh root@namenode "ambari-agent restart"

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Explorer

yes I executed the command

The log files indicate same error on host

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Guru

Try this:

1. Run /home/horton/start_all_services.sh

2. Wait 5 minutes

3. If Hadoop services are not started after 5 minutes, terminate your EC2 instance and create a new one because something failed in your VM

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Explorer

it works now.. thanks for all your help

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New Contributor

It worked for me by restarting the ambari service. But as Rich suggested we need to wait for 5 mins to get all service restarted. Thanks Rich.

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New Contributor

Hello, can someone tell me how to scp to the practice EC2, copy my notes to my local before I terminate the instance.

I use the Public DNS:22, and chose the key file, but it still prompts me the user name and password, i tried U: horton and P: hadoop, cannot pass the authentication.