Lab4B: Sharded Key/Value Server

[hhow09]

Part B: Sharded Key/Value Server (60 points)

• http://nil.csail.mit.edu/6.824/2021/labs/lab-shard.html

Task

Your first task is to pass the very first shardkv test. 
In this test, there is only a single assignment of shards, so your code should be very similar to that of your Lab 3 server. 
The biggest modification will be to have your server detect when a configuration happens and start accepting requests whose keys match shards that it now owns. 

Task

Implement shard migration during configuration changes. 
Make sure that all servers in a replica group do the migration at the same point in the sequence of operations they execute, so that they all either accept or reject concurrent client requests. 
You should focus on passing the second test ("join then leave") before working on the later tests. 
You are done with this task when you pass all tests up to, but not including, TestDelete.