Before this PR, the timeout caused by leader election returns:
```
14:45:37 etcd2 | 2015-08-12 14:45:37.786349 E | etcdhttp: got unexpected
response error (etcdserver: request timed out)
```
After this PR:
```
15:52:54 etcd1 | 2015-08-12 15:52:54.389523 E | etcdhttp: etcdserver:
request timed out, possibly due to leader down
```
Conflicts:
etcdserver/raft.go
Before this PR, it may error like this:
```
--- FAIL: TestUpdateMember-2 (0.00s)
server_test.go:950: action =
[{ApplyConfChange:ConfChangeUpdateNode []}
{ProposeConfChange:ConfChangeUpdateNode []}], want
[{ProposeConfChange:ConfChangeUpdateNode []}
{ApplyConfChange:ConfChangeUpdateNode []}]
```
This fixes the test by recording the proposal event in time.
ForceGosched() performs bad when GOMAXPROCS>1. When GOMAXPROCS=1, it
could promise that other goroutines run long enough
because it always yield the processor to other goroutines. But it cannot
yield processor to goroutine running on other processors. So when
GOMAXPROCS>1, the yield may finish when goroutine on the other
processor just runs for little time.
Here is a test to confirm the case:
```
package main
import (
"fmt"
"runtime"
"testing"
)
func ForceGosched() {
// possibility enough to sched up to 10 go routines.
for i := 0; i < 10000; i++ {
runtime.Gosched()
}
}
var d int
func loop(c chan struct{}) {
for {
select {
case <-c:
for i := 0; i < 1000; i++ {
fmt.Sprintf("come to time %d", i)
}
d++
}
}
}
func TestLoop(t *testing.T) {
c := make(chan struct{}, 1)
go loop(c)
c <- struct{}{}
ForceGosched()
if d != 1 {
t.Fatal("d is not incremented")
}
}
```
`go test -v -race` runs well, but `GOMAXPROCS=2 go test -v -race` fails.
Change the functionality to waiting for schedule to happen.
After this PR, only cluster's interface Cluster is exposed, which makes
code much cleaner. And it avoids external packages to rely on cluster
struct in the future.
1. Persist the cluster version change through raft. When the member is restarted, it can recover
the previous known decided cluster version.
2. When there is a new leader, it is forced to do a version checking immediately. This helps to
update the first cluster version fast.
Add remotes to rafthttp, who help newly joined members catch up the
progress of the cluster. It supports basic message sending to remote, and
has no stream connection for simplicity. remotes will not be used
after the latest peers have been added into rafthttp.
Encoding store into json snapshot has quite high CPU cost. And it
will block for a while. This commit makes the encoding process non-
blocking by running it in another go-routine.
raft relies on the link layer to report the status of the sent snapshot.
If the snapshot is still sending, the replication to that remote peer will
be paused. If the snapshot finish sending, the replication will begin
optimistically after electionTimeout. If the snapshot fails, raft will
try to resend it.
WAL should control the cut logic itself. We want to do falloc to
per allocate the space for a segmented wal file at the beginning
and cut it when it size reaches the limit.
* coreos/master:
rafthttp: fix import
raft: should not decrease match and next when handling out of order msgAppResp
Fix migration to allow snapshots to have the right IDs
add snapshotted integration test
fix test import loop
fix import loop, add set to types, and fix comments
etcdserver: autodetect v0.4 WALs and upgrade them to v0.5 automatically
wal: add a bench for write entry
rafthttp: add streaming server and client
dep: use vendored imports in codegangsta/cli
dep: bump golang.org/x/net/context
Conflicts:
etcdserver/server.go
etcdserver/server_test.go
migrate/snapshot.go
Yicheng Qin