[HDDS-11116] OM state machine move to readonly mode on failure

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Won't Do
• Labels: pull-request-available
• Assignee: Sumit Agrawal
• Reporter: Sumit Agrawal
• Created: 08/Jul/24 06:23
• Updated: 14/Aug/24 05:19
• Resolved: 14/Aug/24 05:19

Description

When OM statemachine receives any unknown failure (other than IOException type), it results in termination of OM.

Its observed that same failure is applied to other om nodes, while applyTransaction, as raft log is already replicated to minimum number of nodes in quorum before applyTransaction.

 

Till recovery method is not applied, OM remains down. So as to provide read only service, can move OM to read only mode, where read operation is allowed over leader.

 

Few points in consideration:

1. Need block applyTransaction of raft log in readonly mode to avoid running transaction on previous failed operation
2. Need support Read operation over read only mode (as leader election will happen, but leader will not be ready till latest transaction is updated)

 

Issue Links

• links to: GitHub Pull Request #6928