[#409] node: Fetch last bootstrap info on startup

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

cmd/frostfs-node/netmap.go

@@ -256,21 +256,10 @@ func initNetmapState(c *cfg) {
 	epoch, err := c.cfgNetmap.wrapper.Epoch()
 	fatalOnErrDetails("could not initialize current epoch number", err)
 
-	ni, err := c.netmapLocalNodeState(epoch)
+	ni, err := c.netmapInitLocalNodeState(epoch)
 	fatalOnErrDetails("could not init network state", err)
 
-	stateWord := "undefined"
-
-	if ni != nil {
-		switch {
-		case ni.IsOnline():
-			stateWord = "online"
-		case ni.IsOffline():
-			stateWord = "offline"
-		case ni.IsMaintenance():
-			stateWord = "maintenance"
-		}
-	}
+	stateWord := nodeState(ni)
 
 	c.log.Info(logs.FrostFSNodeInitialNetworkState,
 		zap.Uint64("epoch", epoch),
@@ -282,6 +271,55 @@ func initNetmapState(c *cfg) {
 	c.handleLocalNodeInfo(ni)
 }
 
+func nodeState(ni *netmapSDK.NodeInfo) string {
+	if ni != nil {
+		switch {
+		case ni.IsOnline():
+			return "online"
+		case ni.IsOffline():
+			return "offline"
+		case ni.IsMaintenance():
+			return "maintenance"
+		}
+	}
+	return "undefined"
+}
+
+func (c *cfg) netmapInitLocalNodeState(epoch uint64) (*netmapSDK.NodeInfo, error) {
+	nmNodes, err := c.cfgNetmap.wrapper.GetCandidates()
+	if err != nil {
+		return nil, err
+	}
+
+	var candidate *netmapSDK.NodeInfo
+	for i := range nmNodes {
+		if bytes.Equal(nmNodes[i].PublicKey(), c.binPublicKey) {
+			candidate = &nmNodes[i]
+			break
+		}
+	}
+
+	node, err := c.netmapLocalNodeState(epoch)
+	if err != nil {
+		return nil, err
+	}
+
+	if candidate == nil {
+		return node, nil
+	}
+
+	nmState := nodeState(node)
+	candidateState := nodeState(candidate)
+	if nmState != candidateState {
+		// This happens when the node was switched to maintenance without epoch tick.
+		// We expect it to continue staying in maintenance.
+		c.log.Info("candidate status is different from the netmap status, the former takes priority",
+			zap.String("netmap", nmState),
+			zap.String("candidate", candidateState))
+	}
+	return candidate, nil
+}
+
 func (c *cfg) netmapLocalNodeState(epoch uint64) (*netmapSDK.NodeInfo, error) {
 	// calculate current network state
 	nm, err := c.cfgNetmap.wrapper.GetNetMapByEpoch(epoch)