mirror of https://github.com/status-im/consul.git
352 lines
10 KiB
Go
352 lines
10 KiB
Go
package consul
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import (
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"fmt"
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"net"
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"path/filepath"
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"strings"
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"time"
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"github.com/hashicorp/consul/agent/metadata"
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"github.com/hashicorp/consul/lib"
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"github.com/hashicorp/raft"
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"github.com/hashicorp/serf/serf"
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)
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const (
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// StatusReap is used to update the status of a node if we
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// are handling a EventMemberReap
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StatusReap = serf.MemberStatus(-1)
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// userEventPrefix is pre-pended to a user event to distinguish it
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userEventPrefix = "consul:event:"
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// maxPeerRetries limits how many invalidate attempts are made
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maxPeerRetries = 6
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// peerRetryBase is a baseline retry time
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peerRetryBase = 1 * time.Second
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)
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// setupSerf is used to setup and initialize a Serf
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func (s *Server) setupSerf(conf *serf.Config, ch chan serf.Event, path string, wan bool, wanPort int,
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segment string, listener net.Listener) (*serf.Serf, error) {
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conf.Init()
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if wan {
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conf.NodeName = fmt.Sprintf("%s.%s", s.config.NodeName, s.config.Datacenter)
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} else {
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conf.NodeName = s.config.NodeName
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conf.Tags["wan_join_port"] = fmt.Sprintf("%d", wanPort)
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}
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conf.Tags["role"] = "consul"
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conf.Tags["dc"] = s.config.Datacenter
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conf.Tags["segment"] = segment
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if segment == "" {
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for _, s := range s.config.Segments {
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conf.Tags["sl_"+s.Name] = net.JoinHostPort(s.Advertise, fmt.Sprintf("%d", s.Port))
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}
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}
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conf.Tags["id"] = string(s.config.NodeID)
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conf.Tags["vsn"] = fmt.Sprintf("%d", s.config.ProtocolVersion)
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conf.Tags["vsn_min"] = fmt.Sprintf("%d", ProtocolVersionMin)
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conf.Tags["vsn_max"] = fmt.Sprintf("%d", ProtocolVersionMax)
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conf.Tags["raft_vsn"] = fmt.Sprintf("%d", s.config.RaftConfig.ProtocolVersion)
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conf.Tags["build"] = s.config.Build
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addr := listener.Addr().(*net.TCPAddr)
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conf.Tags["port"] = fmt.Sprintf("%d", addr.Port)
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if s.config.Bootstrap {
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conf.Tags["bootstrap"] = "1"
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}
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if s.config.BootstrapExpect != 0 {
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conf.Tags["expect"] = fmt.Sprintf("%d", s.config.BootstrapExpect)
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}
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if s.config.NonVoter {
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conf.Tags["nonvoter"] = "1"
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}
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if s.config.UseTLS {
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conf.Tags["use_tls"] = "1"
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}
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if s.logger == nil {
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conf.MemberlistConfig.LogOutput = s.config.LogOutput
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conf.LogOutput = s.config.LogOutput
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}
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conf.MemberlistConfig.Logger = s.logger
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conf.Logger = s.logger
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conf.EventCh = ch
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conf.ProtocolVersion = protocolVersionMap[s.config.ProtocolVersion]
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conf.RejoinAfterLeave = s.config.RejoinAfterLeave
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if wan {
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conf.Merge = &wanMergeDelegate{}
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} else {
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conf.Merge = &lanMergeDelegate{
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dc: s.config.Datacenter,
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nodeID: s.config.NodeID,
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nodeName: s.config.NodeName,
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segment: segment,
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}
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}
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// Until Consul supports this fully, we disable automatic resolution.
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// When enabled, the Serf gossip may just turn off if we are the minority
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// node which is rather unexpected.
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conf.EnableNameConflictResolution = false
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if !s.config.DevMode {
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conf.SnapshotPath = filepath.Join(s.config.DataDir, path)
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}
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if err := lib.EnsurePath(conf.SnapshotPath, false); err != nil {
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return nil, err
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}
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return serf.Create(conf)
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}
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// userEventName computes the name of a user event
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func userEventName(name string) string {
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return userEventPrefix + name
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}
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// isUserEvent checks if a serf event is a user event
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func isUserEvent(name string) bool {
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return strings.HasPrefix(name, userEventPrefix)
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}
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// rawUserEventName is used to get the raw user event name
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func rawUserEventName(name string) string {
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return strings.TrimPrefix(name, userEventPrefix)
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}
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// lanEventHandler is used to handle events from the lan Serf cluster
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func (s *Server) lanEventHandler() {
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for {
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select {
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case e := <-s.eventChLAN:
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switch e.EventType() {
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case serf.EventMemberJoin:
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s.lanNodeJoin(e.(serf.MemberEvent))
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s.localMemberEvent(e.(serf.MemberEvent))
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case serf.EventMemberLeave, serf.EventMemberFailed:
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s.lanNodeFailed(e.(serf.MemberEvent))
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s.localMemberEvent(e.(serf.MemberEvent))
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case serf.EventMemberReap:
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s.localMemberEvent(e.(serf.MemberEvent))
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case serf.EventUser:
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s.localEvent(e.(serf.UserEvent))
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case serf.EventMemberUpdate:
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s.localMemberEvent(e.(serf.MemberEvent))
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case serf.EventQuery: // Ignore
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default:
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s.logger.Printf("[WARN] consul: Unhandled LAN Serf Event: %#v", e)
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}
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case <-s.shutdownCh:
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return
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}
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}
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}
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// localMemberEvent is used to reconcile Serf events with the strongly
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// consistent store if we are the current leader
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func (s *Server) localMemberEvent(me serf.MemberEvent) {
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// Do nothing if we are not the leader
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if !s.IsLeader() {
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return
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}
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// Check if this is a reap event
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isReap := me.EventType() == serf.EventMemberReap
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// Queue the members for reconciliation
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for _, m := range me.Members {
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// Change the status if this is a reap event
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if isReap {
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m.Status = StatusReap
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}
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select {
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case s.reconcileCh <- m:
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default:
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}
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}
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}
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// localEvent is called when we receive an event on the local Serf
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func (s *Server) localEvent(event serf.UserEvent) {
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// Handle only consul events
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if !strings.HasPrefix(event.Name, "consul:") {
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return
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}
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switch name := event.Name; {
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case name == newLeaderEvent:
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s.logger.Printf("[INFO] consul: New leader elected: %s", event.Payload)
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// Trigger the callback
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if s.config.ServerUp != nil {
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s.config.ServerUp()
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}
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case isUserEvent(name):
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event.Name = rawUserEventName(name)
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s.logger.Printf("[DEBUG] consul: User event: %s", event.Name)
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// Trigger the callback
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if s.config.UserEventHandler != nil {
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s.config.UserEventHandler(event)
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}
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default:
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s.logger.Printf("[WARN] consul: Unhandled local event: %v", event)
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}
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}
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// lanNodeJoin is used to handle join events on the LAN pool.
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func (s *Server) lanNodeJoin(me serf.MemberEvent) {
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for _, m := range me.Members {
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ok, serverMeta := metadata.IsConsulServer(m)
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if !ok || serverMeta.Segment != "" {
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continue
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}
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s.logger.Printf("[INFO] consul: Adding LAN server %s", serverMeta)
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// Update server lookup
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s.serverLookup.AddServer(serverMeta)
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// If we're still expecting to bootstrap, may need to handle this.
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if s.config.BootstrapExpect != 0 {
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s.maybeBootstrap()
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}
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// Kick the join flooders.
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s.FloodNotify()
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}
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}
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// maybeBootstrap is used to handle bootstrapping when a new consul server joins.
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func (s *Server) maybeBootstrap() {
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// Bootstrap can only be done if there are no committed logs, remove our
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// expectations of bootstrapping. This is slightly cheaper than the full
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// check that BootstrapCluster will do, so this is a good pre-filter.
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index, err := s.raftStore.LastIndex()
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if err != nil {
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s.logger.Printf("[ERR] consul: Failed to read last raft index: %v", err)
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return
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}
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if index != 0 {
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s.logger.Printf("[INFO] consul: Raft data found, disabling bootstrap mode")
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s.config.BootstrapExpect = 0
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return
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}
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// Scan for all the known servers.
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members := s.serfLAN.Members()
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var servers []metadata.Server
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for _, member := range members {
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valid, p := metadata.IsConsulServer(member)
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if !valid {
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continue
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}
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if p.Datacenter != s.config.Datacenter {
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s.logger.Printf("[ERR] consul: Member %v has a conflicting datacenter, ignoring", member)
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continue
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}
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if p.Expect != 0 && p.Expect != s.config.BootstrapExpect {
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s.logger.Printf("[ERR] consul: Member %v has a conflicting expect value. All nodes should expect the same number.", member)
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return
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}
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if p.Bootstrap {
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s.logger.Printf("[ERR] consul: Member %v has bootstrap mode. Expect disabled.", member)
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return
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}
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servers = append(servers, *p)
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}
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// Skip if we haven't met the minimum expect count.
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if len(servers) < s.config.BootstrapExpect {
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return
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}
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// Query each of the servers and make sure they report no Raft peers.
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for _, server := range servers {
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var peers []string
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// Retry with exponential backoff to get peer status from this server
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for attempt := uint(0); attempt < maxPeerRetries; attempt++ {
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if err := s.connPool.RPC(s.config.Datacenter, server.Addr, server.Version,
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"Status.Peers", server.UseTLS, &struct{}{}, &peers); err != nil {
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nextRetry := time.Duration((1 << attempt) * peerRetryBase)
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s.logger.Printf("[ERR] consul: Failed to confirm peer status for %s: %v. Retrying in "+
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"%v...", server.Name, err, nextRetry.String())
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time.Sleep(nextRetry)
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} else {
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break
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}
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}
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// Found a node with some Raft peers, stop bootstrap since there's
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// evidence of an existing cluster. We should get folded in by the
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// existing servers if that's the case, so it's cleaner to sit as a
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// candidate with no peers so we don't cause spurious elections.
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// It's OK this is racy, because even with an initial bootstrap
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// as long as one peer runs bootstrap things will work, and if we
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// have multiple peers bootstrap in the same way, that's OK. We
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// just don't want a server added much later to do a live bootstrap
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// and interfere with the cluster. This isn't required for Raft's
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// correctness because no server in the existing cluster will vote
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// for this server, but it makes things much more stable.
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if len(peers) > 0 {
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s.logger.Printf("[INFO] consul: Existing Raft peers reported by %s, disabling bootstrap mode", server.Name)
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s.config.BootstrapExpect = 0
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return
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}
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}
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// Attempt a live bootstrap!
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var configuration raft.Configuration
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var addrs []string
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minRaftVersion, err := ServerMinRaftProtocol(members)
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if err != nil {
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s.logger.Printf("[ERR] consul: Failed to read server raft versions: %v", err)
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}
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for _, server := range servers {
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addr := server.Addr.String()
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addrs = append(addrs, addr)
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var id raft.ServerID
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if minRaftVersion >= 3 {
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id = raft.ServerID(server.ID)
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} else {
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id = raft.ServerID(addr)
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}
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peer := raft.Server{
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ID: id,
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Address: raft.ServerAddress(addr),
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}
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configuration.Servers = append(configuration.Servers, peer)
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}
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s.logger.Printf("[INFO] consul: Found expected number of peers, attempting bootstrap: %s",
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strings.Join(addrs, ","))
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future := s.raft.BootstrapCluster(configuration)
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if err := future.Error(); err != nil {
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s.logger.Printf("[ERR] consul: Failed to bootstrap cluster: %v", err)
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}
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// Bootstrapping complete, or failed for some reason, don't enter this
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// again.
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s.config.BootstrapExpect = 0
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}
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// lanNodeFailed is used to handle fail events on the LAN pool.
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func (s *Server) lanNodeFailed(me serf.MemberEvent) {
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for _, m := range me.Members {
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ok, serverMeta := metadata.IsConsulServer(m)
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if !ok || serverMeta.Segment != "" {
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continue
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}
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s.logger.Printf("[INFO] consul: Removing LAN server %s", serverMeta)
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// Update id to address map
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s.serverLookup.RemoveServer(serverMeta)
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}
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}
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