Is there any way to pass parameters to a custom script in ambari ?

[#1]

I'm working on a POC to take NN metadata backup. For this, i'm compressing the NN's metadata using a custom script that i will call through ambari API. (https://community.hortonworks.com/articles/139788/running-custom-scripts-through-ambari.html) . If i simply hardcode the datadirectory name it will work. However, i'm looking to pass them as an argument while submitting the request. Anyone aware of the method ?

[#2 · Accepted solution]

Hi @Narendra Neerukonda,

As the Article Says :

Note: You can add comma separated inputs if you need any inputs for the script.

you can actually pass the parameters to the script like this :

curl -u <username>:<password> -X POST -H 'X-Requested-By:ambari' -d'{"RequestInfo":{"context":"Execute my action", "action":"my_action", "parameters" : {"my_input" : "value"}}, "Requests/resource_filters":[{"service_name":"", "component_name":"", "hosts":"<comma_separated_host_names>"}]' http://<ambari_host>:<port>/api/v1/clusters/<cluster_name>/requests

Where "my_input" is paramter name and "value" is the value to be passed.

Hope this helps. Please accept answer and vote up if it did.

[#3]

My previous comment is still under moderation but the solution is: Apparently, it's mandatory to pass value for service_name and component_name.

[#4]

Thanks @Akhil S Naik ,

I'm able to pass the parameters now.

However, there is a problem i'm facing when i'm submitting the request with "Requests/resource_filters".

If i do the below, the custom script is executed but, it gets executed on all hosts instead of only server1 and server2:

-d '{"RequestInfo":{"context":"Execute an action", "action" : "stream_file", "parameters" : {"file" : "/hadoop_mount/hdfs.tar.gz"},"service_name" : "", "component_name":"", "hosts":"server1,server2"}}' http://ambari-server:8080/api/v1/clusters/<clustername>/requests

To resolve this i added below as per from your above sample:

-d '{"RequestInfo":{"context":"Execute an action", "action" : "stream_file", "parameters" : {"file" : "/hadoop01/hdfs.tar.gz"}},"Requests/resource_filters":[{"service_name" : "", "component_name":"", "hosts":"server1,server2"}]}' http://ambari-server:8080/api/v1/clusters/<clustername>/requests

But when i submit this, even though the command goes to only the required hosts, it just goes into hung state (grey colored gears - Execution doesn't start at all.) Any idea on what might be blocking the execution ?

With Regards,

Narendra

To the users who will come here in future, the parameter you passed will be available from the configs (config = Script.get_config()) inside your code and at config['roleParams']['my_input'] to be precise.

[#5]

The above question and the entire response thread below was originally posted in the Community Help track. On Sat Jul 6 17:30 UTC 2019, a member of the HCC moderation staff moved it to the Cloud & Operations track. The Community Help Track is intended for questions about using the HCC site itself, not technical questions.