Were you checking the correct Node?

We have only one node. There are only limited agents rules are available in SMA. I can't see Systemworkindexer and SystemRuleindexer. What could be the reason?

Could you please check whether agents were enabled in search or not.

Pega Button -> System -> Search

I am working on PRPC 7.1.7 version. Your image says, your PRPC version is not 7.

I can't see them in search. From where i can enable them? What are the OOTB agents which should be always up and running to function the PRPC correctly?

I sent it from PRPC6.3SP1. In 7.1.7 view has been changed. Searching mechanism has been changed to Elastic from Lucene.

Look for the new agent in version 7 instead of the lucene search agents. Thanks.

you can check the status of these agents by following 

DStudio -> Records -> SysAdmin -> Agents - click on Pega-Rules rule set to see status of these agents. If status is enabled then agent should apear in SMA as well.