HA: Caching API: Vsam implementation

[jandadav]

Is your feature request related to a problem? Please describe.
The feature supports the overall Zowe HA plan.

Describe the solution you'd like
Caching API service is developed, based on VSAM as the first implementation. More details about caching api can be found in the HA draft.

Prerequisites

• Update zowe-install-packaging to create the VSAM cluster - @jackjia-ibm
• Set up VSAM cluster on internal testing environment - @balhar-jakub

Tasks

• Implement VSAM storage support - @jandadav
• Document VSAM setup and Caching service - @taban03
• Set up internal test environment to test the VSAM - @balhar-jakub
• Modify/add integration tests to verify concurrency - @achmelo
• Integration tests for install packaging - @taban03
• Integration tests for internal pipeline - @jandadav
• Vsam Concurrent use - @jandadav
• Deploy the Caching Service on Marist - @taban03
• Refactor Vsam Storage implementation after IT are running (@jandadav)

Acceptance Criteria

• ability to configure storage solution for VSAM or in memory
• restart of the caching service won't loose the data (if with persistent storage - VSAM)
• concurrent work with VSAM (multiple caching services and concurrent clients getting data out of VSAM)

[MarkAckert]

This needs a little more runway - which type of VSAM clusters to use? Any other consideration that we're unaware w/ VSAM data?

• Nayer can help with the runway item.
• APIML can take lead on implementation. If possible to write this with Java, use that.
• Review design with TSC and/or Architecture call

@balhar-jakub @jalel01

[CarsonCook]

The Zowe HA plan states change desktop/gateway to utilize Caching API and convert them to be stateless. What stateful information is in the gateway that isn't security sensitive?

[balhar-jakub]

The only state which is actually kept within the Gateway is the list of the invalidated JWT tokens.

For the tokens I don't think that there is any issue with the Caching Service having the access towards the invalidated tokens.

As for other services accessing this information. I don't think that the other services should have access to the data.

I think that the key switch is in the desktop as there are stored data around the user behavior and state of the virtual desktop.