Smart Data Streaming on HANA : Data service discovery not working when running SDS on multiple host

[former_member183029]

Hi,

I previously had set up SDS on HANA where streaming-server was running on one node and I was able to run ESP projects on that successfully.

No I want to check how it works when there are multiple node as streaming node. So I did the following :

1. I have three hosts, let's assume their DNS full names are hana, sds1 and sds2. I installed HANA and SDS in hana system and added sds1 and sds2 as streaming host.
   ./hdblcm - -action=add_hosts - -addhosts=< Smart_Data_Streaming _host_full_DNS>:role=streaming
   Everything works out pretty well and HANA system was up and running with two streaming host.
   
   
2. Next I installed unixODBC driver in sds1 host, as mentioned in the admin and configuration guide of SDS and then created the symbolic link as stated there. Also added the line LD_LIBRARY_PATH="/usr/local/lib":$LD_LIBRARY_PATH export LD_LIBRARY_PATH in the file /hana/shared/<SID>/streaming/STREAMING.sh as per the document. After that restarted the HANA system. Also created a datasource in the .odbc.ini file of /usr/sap/<SID>/home as mentioned in the document.
3. Now I added the streaming host sds1 in the eclipse server view and then created a service using the datasource. When I try to discover schemas from that service, it throws an error(see the attached image).

While setting up the same for one host which I did previously, I followed exactly the same steps and it worked! Is there something that I am missing here ?

Also my intention of setting up multiple streaming server was to create a streaming cluster and see how the load balancing and failover works. I saw in the document that ESP cockpit can be opened in web browser with the link as https://<sds1>/cockpit

It does not work for me. What all needs to be done for this cluster configuration ? I have followed the steps mentioned in the document regarding running the cockpit.sh file. Even after that the link does not work for me.

Regards,

Subhankar

[RobertWaywell · Accepted solution]

Hi Subhankar,

I was able to test this today. I started with a working HANA SDS system with a working ODBC data service. The system initially had a single streaming node. I added the 2nd streaming node/host then tested stopping & starting a project and running Discover against the existing ODBC data service. For my system everything is working cleanly. Note that at this point, I haven't even configured the ODBC connection on the 2nd node.

Given the test I just did, I expect that you have an ODBC configuration issue that is independent of using multiple SDS nodes in a cluster. As a diagnostic step you may want to try removing the 2nd streaming host and verifying whether or not your ODC Data Service discovery works on this system with a single streaming host.

Thanks

[former_member183029 · Accepted solution]

Hi Robert,

Thank you for your reply. I have removed the 2nd host and checked. But the 1st host discovery didn't work. However I had some doubt regarding the LD_LIBRARY_PATH configuration so I reverted that and now discovery works!

            Which means that the host is getting connected and I only have .odbc.ini file in /usr/sap/<SID>/home having the service configured, but I don't have the LD_LIBRARY_PATH configured as per the document.

Could you please tell me when is this LD_LIBRARY_PATH configuration necessary ?

[RobertWaywell · Accepted solution]

If you followed the instructions in the product documentation or in the document here on the SCN for installing the ODBC Driver Manager, then the ODBC Driver Manager will be located in the /usr/local/lib directory. That location is not in the LD_LIBRARY_PATH by default. The instructions to update the LD_LIBRARY_PATH setting the STREAMING.sh are there to make the /usr/local/lib directory part of that path and hence make the ODBC Driver Manager visible to the Streaming server.

If you already have an ODBC Driver Manager installed on the system and/or you place the ODBC Driver Manager in a different directory location that is already included in the LD_LIBRARY_PATH then you would not need to edit the STREAMING.sh to add the /usr/local/lib directory to the path.

[RobertWaywell]

For your second question on using ESP Cockpit, check out the documentation on

Starting SAP ESP Cockpit - SAP HANA Smart Data Streaming: Configuration and Administration Guide - S...

The ESP Cockpit is not started automatically so you will need to start the process before you can connect from the browser.

Also note that SAP ESP Cockpit is listening on an SSL connection so the default URL will have the form: https://<hostname>:4283/cockpit

[former_member183029]

I am following the same guide for this. Briefly, I did the following :

1.     First I logged in to HANA host as <sid>adm user and logged in to streamingcluster admin utility as described in the document. Screenshot for the whole operation is below.

2.     Next I logged in to the 1st streaming host again as <sid>adm user and execute ./cockpit.sh as per the document. See the screenshot below.

After this I am trying to open the following url :

https://<first sds host dns full name>:4283/cockpit

But this url is not accessible. Am I missing something here ?

[former_member183029]

This was a proxy issue and thanks to Robert, I was able to resolve it.