// handleJoinRequest handles a request to join the cluster
func (r *rpc) handleJoinRequest(req *internal.JoinRequest) (*internal.JoinResponse, error) {
r.traceCluster("join request from: %v", *req.Addr)
node, err := func() (*NodeInfo, error) {
// attempt to create the node
node, err := r.store.CreateNode(*req.Addr)
// if it exists, return the existing node
if err == ErrNodeExists {
node, err = r.store.NodeByHost(*req.Addr)
if err != nil {
return node, err
}
r.logger.Printf("existing node re-joined: id=%v addr=%v", node.ID, node.Host)
} else if err != nil {
return nil, fmt.Errorf("create node: %v", err)
}
peers, err := r.store.Peers()
if err != nil {
return nil, fmt.Errorf("list peers: %v", err)
}
// If we have less than 3 nodes, add them as raft peers if they are not
// already a peer
if len(peers) < MaxRaftNodes && !raft.PeerContained(peers, *req.Addr) {
r.logger.Printf("adding new raft peer: nodeId=%v addr=%v", node.ID, *req.Addr)
if err = r.store.AddPeer(*req.Addr); err != nil {
return node, fmt.Errorf("add peer: %v", err)
}
}
return node, err
}()
nodeID := uint64(0)
if node != nil {
nodeID = node.ID
}
if err != nil {
return nil, err
}
// get the current raft peers
peers, err := r.store.Peers()
if err != nil {
return nil, fmt.Errorf("list peers: %v", err)
}
return &internal.JoinResponse{
Header: &internal.ResponseHeader{
OK: proto.Bool(true),
},
EnableRaft: proto.Bool(raft.PeerContained(peers, *req.Addr)),
RaftNodes: peers,
NodeID: proto.Uint64(nodeID),
}, err
}
func (r *localRaft) open() error {
r.closing = make(chan struct{})
s := r.store
// Setup raft configuration.
config := raft.DefaultConfig()
config.LogOutput = ioutil.Discard
if s.clusterTracingEnabled {
config.Logger = s.Logger
}
config.HeartbeatTimeout = s.HeartbeatTimeout
config.ElectionTimeout = s.ElectionTimeout
config.LeaderLeaseTimeout = s.LeaderLeaseTimeout
config.CommitTimeout = s.CommitTimeout
// If no peers are set in the config or there is one and we are it, then start as a single server.
if len(s.peers) <= 1 {
config.EnableSingleNode = true
// Ensure we can always become the leader
config.DisableBootstrapAfterElect = false
// Don't shutdown raft automatically if we renamed our hostname back to a previous name
config.ShutdownOnRemove = false
}
// Build raft layer to multiplex listener.
r.raftLayer = newRaftLayer(s.RaftListener, s.RemoteAddr)
// Create a transport layer
r.transport = raft.NewNetworkTransport(r.raftLayer, 3, 10*time.Second, config.LogOutput)
// Create peer storage.
r.peerStore = raft.NewJSONPeers(s.path, r.transport)
peers, err := r.peerStore.Peers()
if err != nil {
return err
}
// For single-node clusters, we can update the raft peers before we start the cluster if the hostname
// has changed.
if config.EnableSingleNode {
if err := r.peerStore.SetPeers([]string{s.RemoteAddr.String()}); err != nil {
return err
}
peers = []string{s.RemoteAddr.String()}
}
// If we have multiple nodes in the cluster, make sure our address is in the raft peers or
// we won't be able to boot into the cluster because the other peers will reject our new hostname. This
// is difficult to resolve automatically because we need to have all the raft peers agree on the current members
// of the cluster before we can change them.
if len(peers) > 0 && !raft.PeerContained(peers, s.RemoteAddr.String()) {
s.Logger.Printf("%v is not in the list of raft peers. Please update %v/peers.json on all raft nodes to have the same contents.", s.RemoteAddr.String(), s.Path())
return fmt.Errorf("peers out of sync: %v not in %v", s.RemoteAddr.String(), peers)
}
// Create the log store and stable store.
store, err := raftboltdb.NewBoltStore(filepath.Join(s.path, "raft.db"))
if err != nil {
return fmt.Errorf("new bolt store: %s", err)
}
r.raftStore = store
// Create the snapshot store.
snapshots, err := raft.NewFileSnapshotStore(s.path, raftSnapshotsRetained, os.Stderr)
if err != nil {
return fmt.Errorf("file snapshot store: %s", err)
}
// Create raft log.
ra, err := raft.NewRaft(config, (*storeFSM)(s), store, store, snapshots, r.peerStore, r.transport)
if err != nil {
return fmt.Errorf("new raft: %s", err)
}
r.raft = ra
r.wg.Add(1)
go r.logLeaderChanges()
return nil
}