Setting up High availability for HANA Cloud Connector
The HANA Cloud Connector is a crucial component when it comes to exposing your on-premise business data the HANA Cloud Platform. In the last few months, I have been asked few questions around this topic. Hence, in this blog post, I am going to explain how to setup and configure HANA Cloud Connector for High availability.
I am going to setup two HANA Cloud Connectors – Master and Shadow. For demonstration purposes, I am going to have both the SCCs on my laptop but running from different ports. Ideally, they will be installed on different machines.
Install the Master HANA Cloud Connector
Download and install SCC from SAP Development Tools
Proceed with the Installation wizard. Ensure that you select “Master” for the first SCC which you install.
I have given the port as 8443 (default port). There is a How-To-Guide on how to install and configure HANA Cloud Connector.
In the below screen you can see that I have configured my Master SCC to point to my HCP Trial account and I have also configured a connection to one of my ABAP backend systems.
To enable High availability, we need to first go to the setting (top right-hand corner) and enable the checkbox shown below
Install the Shadow HANA Cloud Connector
Follow the same steps as mentioned above to install the HANA Cloud Connector. The only difference being, select “Shadow” for installation type and chose a different port. Since I have both on the same machine (for demonstration purpose), I have given a different port – 8434
Once you login to the Shadow SCC, you will see limited options. The first activity would be to connect to the master SCC.
Provide the host name and port where the master SCC is running and click on connect.
Check Interval – represents the time-frequency in which the Shadow pings the master. If the master is not reachable for a while (represented by the takeover delay), the Shadow tries to take over the master role and to establish the tunnel to SAP HANA Cloud Platform. I personally think 60 seconds is a long time and should be carefully considered. I am going to accept the defaults and proceed.
Once this your provide the Administrators detail and successfully connect to the master, you will notice all the settings (including mappings/rules) will be copied across. This will be in read-only mode.
Notice all the system mappings are copied across.
Test the failover
Before I test the failover, I am first going to my HCP account to check the connectivity. I can see a “Shadow Instance” showing up in the connectivity. For demonstration purposes, I have got my Shadow SCC on 2.8 version and master on 2.7 version. Ideally, we should have them on the latest versions.
I am first going to check if my changes in master configuration replicate to the salve. Hence, I am going to change the resources of U3F system.
I am going to change the resources from “/” to “sap/opu/odata”
When I login to my Shadow SCC, I should be able to see the changes being reflected.
I will shut down my master SCC instance to check if the Shadow SCC connects. Since I have given the check interval as 60 seconds and takeover delay as 30 seconds, it will few take seconds for the Shadow to take over.
If I quickly go to my HCP account and check the SCC connectivity, there should be none for few seconds.
After few seconds, once the Shadow has identified that the master has gone down, it assumes the role of a master and the salve SCC establishes a connection to the HCP account.
Notice that the Shadow has already taken the role of a master SCC. I could confirm this with the version of the SCC.
Now when I login into the Shadow SCC, I will get to see a different UI. Yes, you will start to the see the same screen which you used to see in the master SCC. From here on, the Shadow SCC acts as a Master SCC and when the original master SCC comes online, it will take the role as a Shadow SCC.
The original Master SCC, will be read-only when it comes back online
When the original master SCC comes online and if you want to switch the roles, you can click on the “switch roles” button.
Hope you found this info useful.