package cluster // import "github.com/docker/docker/daemon/cluster" import ( "context" "fmt" "path/filepath" "strings" "sync" "time" types "github.com/docker/docker/api/types/swarm" "github.com/docker/docker/daemon/cluster/executor/container" lncluster "github.com/docker/docker/libnetwork/cluster" swarmapi "github.com/docker/swarmkit/api" swarmallocator "github.com/docker/swarmkit/manager/allocator/cnmallocator" swarmnode "github.com/docker/swarmkit/node" "github.com/pkg/errors" "github.com/sirupsen/logrus" "google.golang.org/grpc" "google.golang.org/grpc/codes" "google.golang.org/grpc/status" ) // nodeRunner implements a manager for continuously running swarmkit node, restarting them with backoff delays if needed. type nodeRunner struct { nodeState mu sync.RWMutex done chan struct{} // closed when swarmNode exits ready chan struct{} // closed when swarmNode becomes active reconnectDelay time.Duration config nodeStartConfig repeatedRun bool cancelReconnect func() stopping bool cluster *Cluster // only for accessing config helpers, never call any methods. TODO: change to config struct } // nodeStartConfig holds configuration needed to start a new node. Exported // fields of this structure are saved to disk in json. Unexported fields // contain data that shouldn't be persisted between daemon reloads. type nodeStartConfig struct { // LocalAddr is this machine's local IP or hostname, if specified. LocalAddr string // RemoteAddr is the address that was given to "swarm join". It is used // to find LocalAddr if necessary. RemoteAddr string // ListenAddr is the address we bind to, including a port. ListenAddr string // AdvertiseAddr is the address other nodes should connect to, // including a port. AdvertiseAddr string // DataPathAddr is the address that has to be used for the data path DataPathAddr string // DefaultAddressPool contains list of subnets DefaultAddressPool []string // SubnetSize contains subnet size of DefaultAddressPool SubnetSize uint32 // DataPathPort contains Data path port (VXLAN UDP port) number that is used for data traffic. DataPathPort uint32 // JoinInProgress is set to true if a join operation has started, but // not completed yet. JoinInProgress bool joinAddr string forceNewCluster bool joinToken string lockKey []byte autolock bool availability types.NodeAvailability } func (n *nodeRunner) Ready() chan error { c := make(chan error, 1) n.mu.RLock() ready, done := n.ready, n.done n.mu.RUnlock() go func() { select { case <-ready: case <-done: } select { case <-ready: default: n.mu.RLock() c <- n.err n.mu.RUnlock() } close(c) }() return c } func (n *nodeRunner) Start(conf nodeStartConfig) error { n.mu.Lock() defer n.mu.Unlock() n.reconnectDelay = initialReconnectDelay return n.start(conf) } func (n *nodeRunner) start(conf nodeStartConfig) error { var control string if isWindows { control = `\\.\pipe\` + controlSocket } else { control = filepath.Join(n.cluster.runtimeRoot, controlSocket) } joinAddr := conf.joinAddr if joinAddr == "" && conf.JoinInProgress { // We must have been restarted while trying to join a cluster. // Continue trying to join instead of forming our own cluster. joinAddr = conf.RemoteAddr } // Hostname is not set here. Instead, it is obtained from // the node description that is reported periodically swarmnodeConfig := swarmnode.Config{ ForceNewCluster: conf.forceNewCluster, ListenControlAPI: control, ListenRemoteAPI: conf.ListenAddr, AdvertiseRemoteAPI: conf.AdvertiseAddr, NetworkConfig: &swarmallocator.NetworkConfig{ DefaultAddrPool: conf.DefaultAddressPool, SubnetSize: conf.SubnetSize, VXLANUDPPort: conf.DataPathPort, }, JoinAddr: joinAddr, StateDir: n.cluster.root, JoinToken: conf.joinToken, Executor: container.NewExecutor( n.cluster.config.Backend, n.cluster.config.PluginBackend, n.cluster.config.ImageBackend, n.cluster.config.VolumeBackend, ), HeartbeatTick: n.cluster.config.RaftHeartbeatTick, // Recommended value in etcd/raft is 10 x (HeartbeatTick). // Lower values were seen to have caused instability because of // frequent leader elections when running on flakey networks. ElectionTick: n.cluster.config.RaftElectionTick, UnlockKey: conf.lockKey, AutoLockManagers: conf.autolock, PluginGetter: n.cluster.config.Backend.PluginGetter(), } if conf.availability != "" { avail, ok := swarmapi.NodeSpec_Availability_value[strings.ToUpper(string(conf.availability))] if !ok { return fmt.Errorf("invalid Availability: %q", conf.availability) } swarmnodeConfig.Availability = swarmapi.NodeSpec_Availability(avail) } node, err := swarmnode.New(&swarmnodeConfig) if err != nil { return err } if err := node.Start(context.Background()); err != nil { return err } n.done = make(chan struct{}) n.ready = make(chan struct{}) n.swarmNode = node if conf.joinAddr != "" { conf.JoinInProgress = true } n.config = conf savePersistentState(n.cluster.root, conf) ctx, cancel := context.WithCancel(context.Background()) go func() { n.handleNodeExit(node) cancel() }() go n.handleReadyEvent(ctx, node, n.ready) go n.handleControlSocketChange(ctx, node) return nil } func (n *nodeRunner) handleControlSocketChange(ctx context.Context, node *swarmnode.Node) { for conn := range node.ListenControlSocket(ctx) { n.mu.Lock() if n.grpcConn != conn { if conn == nil { n.controlClient = nil n.logsClient = nil } else { n.controlClient = swarmapi.NewControlClient(conn) n.logsClient = swarmapi.NewLogsClient(conn) // push store changes to daemon go n.watchClusterEvents(ctx, conn) } } n.grpcConn = conn n.mu.Unlock() n.cluster.SendClusterEvent(lncluster.EventSocketChange) } } func (n *nodeRunner) watchClusterEvents(ctx context.Context, conn *grpc.ClientConn) { client := swarmapi.NewWatchClient(conn) watch, err := client.Watch(ctx, &swarmapi.WatchRequest{ Entries: []*swarmapi.WatchRequest_WatchEntry{ { Kind: "node", Action: swarmapi.WatchActionKindCreate | swarmapi.WatchActionKindUpdate | swarmapi.WatchActionKindRemove, }, { Kind: "service", Action: swarmapi.WatchActionKindCreate | swarmapi.WatchActionKindUpdate | swarmapi.WatchActionKindRemove, }, { Kind: "network", Action: swarmapi.WatchActionKindCreate | swarmapi.WatchActionKindUpdate | swarmapi.WatchActionKindRemove, }, { Kind: "secret", Action: swarmapi.WatchActionKindCreate | swarmapi.WatchActionKindUpdate | swarmapi.WatchActionKindRemove, }, { Kind: "config", Action: swarmapi.WatchActionKindCreate | swarmapi.WatchActionKindUpdate | swarmapi.WatchActionKindRemove, }, }, IncludeOldObject: true, }) if err != nil { logrus.WithError(err).Error("failed to watch cluster store") return } for { msg, err := watch.Recv() if err != nil { // store watch is broken errStatus, ok := status.FromError(err) if !ok || errStatus.Code() != codes.Canceled { logrus.WithError(err).Error("failed to receive changes from store watch API") } return } select { case <-ctx.Done(): return case n.cluster.watchStream <- msg: } } } func (n *nodeRunner) handleReadyEvent(ctx context.Context, node *swarmnode.Node, ready chan struct{}) { select { case <-node.Ready(): n.mu.Lock() n.err = nil if n.config.JoinInProgress { n.config.JoinInProgress = false savePersistentState(n.cluster.root, n.config) } n.mu.Unlock() close(ready) case <-ctx.Done(): } n.cluster.SendClusterEvent(lncluster.EventNodeReady) } func (n *nodeRunner) handleNodeExit(node *swarmnode.Node) { err := detectLockedError(node.Err(context.Background())) if err != nil { logrus.Errorf("cluster exited with error: %v", err) } n.mu.Lock() n.swarmNode = nil n.err = err close(n.done) select { case <-n.ready: n.enableReconnectWatcher() default: if n.repeatedRun { n.enableReconnectWatcher() } } n.repeatedRun = true n.mu.Unlock() } // Stop stops the current swarm node if it is running. func (n *nodeRunner) Stop() error { n.mu.Lock() if n.cancelReconnect != nil { // between restarts n.cancelReconnect() n.cancelReconnect = nil } if n.swarmNode == nil { // even though the swarm node is nil we still may need // to send a node leave event to perform any cleanup required. if n.cluster != nil { n.cluster.SendClusterEvent(lncluster.EventNodeLeave) } n.mu.Unlock() return nil } n.stopping = true ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second) defer cancel() n.mu.Unlock() if err := n.swarmNode.Stop(ctx); err != nil && !strings.Contains(err.Error(), "context canceled") { return err } n.cluster.SendClusterEvent(lncluster.EventNodeLeave) <-n.done return nil } func (n *nodeRunner) State() nodeState { if n == nil { return nodeState{status: types.LocalNodeStateInactive} } n.mu.RLock() defer n.mu.RUnlock() ns := n.nodeState if ns.err != nil || n.cancelReconnect != nil { if errors.Is(ns.err, errSwarmLocked) { ns.status = types.LocalNodeStateLocked } else { ns.status = types.LocalNodeStateError } } else { select { case <-n.ready: ns.status = types.LocalNodeStateActive default: ns.status = types.LocalNodeStatePending } } return ns } func (n *nodeRunner) enableReconnectWatcher() { if n.stopping { return } n.reconnectDelay *= 2 if n.reconnectDelay > maxReconnectDelay { n.reconnectDelay = maxReconnectDelay } logrus.Warnf("Restarting swarm in %.2f seconds", n.reconnectDelay.Seconds()) delayCtx, cancel := context.WithTimeout(context.Background(), n.reconnectDelay) n.cancelReconnect = cancel go func() { <-delayCtx.Done() if delayCtx.Err() != context.DeadlineExceeded { return } n.mu.Lock() defer n.mu.Unlock() if n.stopping { return } if err := n.start(n.config); err != nil { n.err = err } }() } // nodeState represents information about the current state of the cluster and // provides access to the grpc clients. type nodeState struct { swarmNode *swarmnode.Node grpcConn *grpc.ClientConn controlClient swarmapi.ControlClient logsClient swarmapi.LogsClient status types.LocalNodeState actualLocalAddr string err error } // IsActiveManager returns true if node is a manager ready to accept control requests. It is safe to access the client properties if this returns true. func (ns nodeState) IsActiveManager() bool { return ns.controlClient != nil } // IsManager returns true if node is a manager. func (ns nodeState) IsManager() bool { return ns.swarmNode != nil && ns.swarmNode.Manager() != nil } // NodeID returns node's ID or empty string if node is inactive. func (ns nodeState) NodeID() string { if ns.swarmNode != nil { return ns.swarmNode.NodeID() } return "" }