My Solutions to course MIT-6.824 2014 Spring labs.

pkg:main, mapreduce

Because the project runs on Windows environment, I send RPCs via "TCP" rather than UNIX-domain sockets. So we should modify some code. On linux, we don't have to do the following.

In woker.go, close the net.Listener when the worker is shut down:

func (wk *Worker) Shutdown(args *ShutdownArgs, res *ShutdownReply) error {
	DPrintf("Shutdown %s\n", wk.name)
	res.Njobs = wk.nJobs
	res.OK = true
	wk.nRPC = 1 // OK, because the same thread reads nRPC
	wk.nJobs--  // Don't count the shutdown RPC
	//** close the port
	wk.l.Close()
	return nil
}

In test_test.go, modify port() function to the real port.

func port(suffix int) string {
	/*s := "/var/tmp/824-"
	s += strconv.Itoa(os.Getuid()) + "/"
	os.Mkdir(s, 0777)
	s += "mr"
	s += strconv.Itoa(os.Getpid()) + "-"
	s += suffix*/
	p := suffix + 5101
	return ":" + strconv.Itoa(p)
}

When we use the function call in common.go, we should dial the right IP:

c, errx := rpc.Dial("tcp", "127.0.0.1"+srv)

run go test to get the result.

pkg:viewservice, pbservice

Use a primary/backup replication for the key/value database, assisted by a view service that decides which machines are alive.

(Developing in Windows is like **, so move to Linux.)

pkg:paxos, kvpaxos

Use Paxos to manage the replication of a key/value store.

pkg:shardmaster, shardkv

Build a key/value storage system that "shards," or partitions, the keys over a set of replica groups.