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Posted to commits@cassandra.apache.org by al...@apache.org on 2016/08/31 19:29:10 UTC

[2/6] cassandra git commit: Forward writes to replacement node when replace_address != broadcast_address

Forward writes to replacement node when replace_address != broadcast_address

Patch by Paulo Motta; reviewed by Richard Low for CASSANDRA-8523


Project: http://git-wip-us.apache.org/repos/asf/cassandra/repo
Commit: http://git-wip-us.apache.org/repos/asf/cassandra/commit/b39d984f
Tree: http://git-wip-us.apache.org/repos/asf/cassandra/tree/b39d984f
Diff: http://git-wip-us.apache.org/repos/asf/cassandra/diff/b39d984f

Branch: refs/heads/cassandra-3.0
Commit: b39d984f7bd682c7638415d65dcc4ac9bcb74e5f
Parents: 6eff082
Author: Paulo Motta <pa...@gmail.com>
Authored: Fri Jun 17 21:09:31 2016 -0300
Committer: Aleksey Yeschenko <al...@apache.org>
Committed: Wed Aug 31 20:21:30 2016 +0100

----------------------------------------------------------------------
 CHANGES.txt                                     |   1 +
 src/java/org/apache/cassandra/gms/Gossiper.java |   5 +-
 .../apache/cassandra/gms/VersionedValue.java    |   6 +
 .../apache/cassandra/locator/TokenMetadata.java |  54 ++++++-
 .../cassandra/service/LoadBroadcaster.java      |   2 +-
 .../cassandra/service/StorageService.java       | 139 +++++++++++++++----
 6 files changed, 177 insertions(+), 30 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/cassandra/blob/b39d984f/CHANGES.txt
----------------------------------------------------------------------
diff --git a/CHANGES.txt b/CHANGES.txt
index 0f7cf0e..d7e9394 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,5 @@
 2.2.8
+ * Forward writes to replacement node when replace_address != broadcast_address (CASSANDRA-8523)
  * Enable repair -pr and -local together (fix regression of CASSANDRA-7450) (CASSANDRA-12522)
  * Fail repair on non-existing table (CASSANDRA-12279)
  * cqlsh copy: fix missing counter values (CASSANDRA-12476)

http://git-wip-us.apache.org/repos/asf/cassandra/blob/b39d984f/src/java/org/apache/cassandra/gms/Gossiper.java
----------------------------------------------------------------------
diff --git a/src/java/org/apache/cassandra/gms/Gossiper.java b/src/java/org/apache/cassandra/gms/Gossiper.java
index 00e3da8..a8f9524 100644
--- a/src/java/org/apache/cassandra/gms/Gossiper.java
+++ b/src/java/org/apache/cassandra/gms/Gossiper.java
@@ -76,6 +76,7 @@ public class Gossiper implements IFailureDetectionEventListener, GossiperMBean
     static {
         SILENT_SHUTDOWN_STATES.addAll(DEAD_STATES);
         SILENT_SHUTDOWN_STATES.add(VersionedValue.STATUS_BOOTSTRAPPING);
+        SILENT_SHUTDOWN_STATES.add(VersionedValue.STATUS_BOOTSTRAPPING_REPLACE);
     }
 
     private volatile ScheduledFuture<?> scheduledGossipTask;
@@ -333,10 +334,12 @@ public class Gossiper implements IFailureDetectionEventListener, GossiperMBean
         if (epState == null)
             return;
 
-        logger.debug("Convicting {} with status {} - alive {}", endpoint, getGossipStatus(epState), epState.isAlive());
         if (!epState.isAlive())
             return;
 
+        logger.debug("Convicting {} with status {} - alive {}", endpoint, getGossipStatus(epState), epState.isAlive());
+
+
         if (isShutdown(endpoint))
         {
             markAsShutdown(endpoint);

http://git-wip-us.apache.org/repos/asf/cassandra/blob/b39d984f/src/java/org/apache/cassandra/gms/VersionedValue.java
----------------------------------------------------------------------
diff --git a/src/java/org/apache/cassandra/gms/VersionedValue.java b/src/java/org/apache/cassandra/gms/VersionedValue.java
index 3ea7bb4..661d3ba 100644
--- a/src/java/org/apache/cassandra/gms/VersionedValue.java
+++ b/src/java/org/apache/cassandra/gms/VersionedValue.java
@@ -65,6 +65,7 @@ public class VersionedValue implements Comparable<VersionedValue>
 
     // values for ApplicationState.STATUS
     public final static String STATUS_BOOTSTRAPPING = "BOOT";
+    public final static String STATUS_BOOTSTRAPPING_REPLACE = "BOOT_REPLACE";
     public final static String STATUS_NORMAL = "NORMAL";
     public final static String STATUS_LEAVING = "LEAVING";
     public final static String STATUS_LEFT = "LEFT";
@@ -133,6 +134,11 @@ public class VersionedValue implements Comparable<VersionedValue>
             return new VersionedValue(value.value);
         }
 
+        public VersionedValue bootReplacing(InetAddress oldNode)
+        {
+            return new VersionedValue(versionString(VersionedValue.STATUS_BOOTSTRAPPING_REPLACE, oldNode.getHostAddress()));
+        }
+
         public VersionedValue bootstrapping(Collection<Token> tokens)
         {
             return new VersionedValue(versionString(VersionedValue.STATUS_BOOTSTRAPPING,

http://git-wip-us.apache.org/repos/asf/cassandra/blob/b39d984f/src/java/org/apache/cassandra/locator/TokenMetadata.java
----------------------------------------------------------------------
diff --git a/src/java/org/apache/cassandra/locator/TokenMetadata.java b/src/java/org/apache/cassandra/locator/TokenMetadata.java
index de16fda..b06c9c8 100644
--- a/src/java/org/apache/cassandra/locator/TokenMetadata.java
+++ b/src/java/org/apache/cassandra/locator/TokenMetadata.java
@@ -26,6 +26,7 @@ import java.util.concurrent.atomic.AtomicReference;
 import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 
+import com.google.common.base.Optional;
 import com.google.common.collect.*;
 import org.apache.commons.lang3.StringUtils;
 import org.slf4j.Logger;
@@ -79,6 +80,9 @@ public class TokenMetadata
     // means we can detect and reject the addition of multiple nodes at the same token
     // before one becomes part of the ring.
     private final BiMultiValMap<Token, InetAddress> bootstrapTokens = new BiMultiValMap<>();
+
+    private final BiMap<InetAddress, InetAddress> replacementToOriginal = HashBiMap.create();
+
     // (don't need to record Token here since it's still part of tokenToEndpointMap until it's done leaving)
     private final Set<InetAddress> leavingEndpoints = new HashSet<>();
     // this is a cache of the calculation from {tokenToEndpointMap, bootstrapTokens, leavingEndpoints}
@@ -185,6 +189,7 @@ public class TokenMetadata
                 tokenToEndpointMap.removeValue(endpoint);
                 topology.addEndpoint(endpoint);
                 leavingEndpoints.remove(endpoint);
+                replacementToOriginal.remove(endpoint);
                 removeFromMoving(endpoint); // also removing this endpoint from moving
 
                 for (Token token : tokens)
@@ -297,13 +302,17 @@ public class TokenMetadata
 
     public void addBootstrapTokens(Collection<Token> tokens, InetAddress endpoint)
     {
+        addBootstrapTokens(tokens, endpoint, null);
+    }
+
+    private void addBootstrapTokens(Collection<Token> tokens, InetAddress endpoint, InetAddress original)
+    {
         assert tokens != null && !tokens.isEmpty();
         assert endpoint != null;
 
         lock.writeLock().lock();
         try
         {
-
             InetAddress oldEndpoint;
 
             for (Token token : tokens)
@@ -313,7 +322,7 @@ public class TokenMetadata
                     throw new RuntimeException("Bootstrap Token collision between " + oldEndpoint + " and " + endpoint + " (token " + token);
 
                 oldEndpoint = tokenToEndpointMap.get(token);
-                if (oldEndpoint != null && !oldEndpoint.equals(endpoint))
+                if (oldEndpoint != null && !oldEndpoint.equals(endpoint) && !oldEndpoint.equals(original))
                     throw new RuntimeException("Bootstrap Token collision between " + oldEndpoint + " and " + endpoint + " (token " + token);
             }
 
@@ -328,6 +337,43 @@ public class TokenMetadata
         }
     }
 
+    public void addReplaceTokens(Collection<Token> replacingTokens, InetAddress newNode, InetAddress oldNode)
+    {
+        assert replacingTokens != null && !replacingTokens.isEmpty();
+        assert newNode != null && oldNode != null;
+
+        lock.writeLock().lock();
+        try
+        {
+            Collection<Token> oldNodeTokens = tokenToEndpointMap.inverse().get(oldNode);
+            if (!replacingTokens.containsAll(oldNodeTokens) || !oldNodeTokens.containsAll(replacingTokens))
+            {
+                throw new RuntimeException(String.format("Node %s is trying to replace node %s with tokens %s with a " +
+                                                         "different set of tokens %s.", newNode, oldNode, oldNodeTokens,
+                                                         replacingTokens));
+            }
+
+            logger.debug("Replacing {} with {}", newNode, oldNode);
+            replacementToOriginal.put(newNode, oldNode);
+
+            addBootstrapTokens(replacingTokens, newNode, oldNode);
+        }
+        finally
+        {
+            lock.writeLock().unlock();
+        }
+    }
+
+    public Optional<InetAddress> getReplacementNode(InetAddress endpoint)
+    {
+        return Optional.fromNullable(replacementToOriginal.inverse().get(endpoint));
+    }
+
+    public Optional<InetAddress> getReplacingNode(InetAddress endpoint)
+    {
+        return Optional.fromNullable((replacementToOriginal.get(endpoint)));
+    }
+
     public void removeBootstrapTokens(Collection<Token> tokens)
     {
         assert tokens != null && !tokens.isEmpty();
@@ -391,6 +437,10 @@ public class TokenMetadata
             tokenToEndpointMap.removeValue(endpoint);
             topology.removeEndpoint(endpoint);
             leavingEndpoints.remove(endpoint);
+            if (replacementToOriginal.remove(endpoint) != null)
+            {
+                logger.debug("Node {} failed during replace.", endpoint);
+            }
             endpointToHostIdMap.remove(endpoint);
             sortedTokens = sortTokens();
             invalidateCachedRings();

http://git-wip-us.apache.org/repos/asf/cassandra/blob/b39d984f/src/java/org/apache/cassandra/service/LoadBroadcaster.java
----------------------------------------------------------------------
diff --git a/src/java/org/apache/cassandra/service/LoadBroadcaster.java b/src/java/org/apache/cassandra/service/LoadBroadcaster.java
index 69fa93d..945dd2f 100644
--- a/src/java/org/apache/cassandra/service/LoadBroadcaster.java
+++ b/src/java/org/apache/cassandra/service/LoadBroadcaster.java
@@ -32,7 +32,7 @@ import org.apache.cassandra.gms.*;
 
 public class LoadBroadcaster implements IEndpointStateChangeSubscriber
 {
-    static final int BROADCAST_INTERVAL = 60 * 1000;
+    static final int BROADCAST_INTERVAL = Integer.getInteger("cassandra.broadcast_interval_ms", 60 * 1000);
 
     public static final LoadBroadcaster instance = new LoadBroadcaster();
 

http://git-wip-us.apache.org/repos/asf/cassandra/blob/b39d984f/src/java/org/apache/cassandra/service/StorageService.java
----------------------------------------------------------------------
diff --git a/src/java/org/apache/cassandra/service/StorageService.java b/src/java/org/apache/cassandra/service/StorageService.java
index 48a291b..9197ab1 100644
--- a/src/java/org/apache/cassandra/service/StorageService.java
+++ b/src/java/org/apache/cassandra/service/StorageService.java
@@ -32,6 +32,7 @@ import javax.management.openmbean.TabularData;
 import javax.management.openmbean.TabularDataSupport;
 
 import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Optional;
 import com.google.common.base.Predicate;
 import com.google.common.collect.*;
 import com.google.common.util.concurrent.*;
@@ -185,6 +186,7 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
     private boolean useStrictConsistency = Boolean.parseBoolean(System.getProperty("cassandra.consistent.rangemovement", "true"));
     private static final boolean allowSimultaneousMoves = Boolean.valueOf(System.getProperty("cassandra.consistent.simultaneousmoves.allow","false"));
     private boolean replacing;
+    private UUID replacingId;
 
     private final StreamStateStore streamStateStore = new StreamStateStore();
 
@@ -194,9 +196,9 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
         if (logger.isDebugEnabled())
             logger.debug("Setting tokens to {}", tokens);
         SystemKeyspace.updateTokens(tokens);
-        tokenMetadata.updateNormalTokens(tokens, FBUtilities.getBroadcastAddress());
         Collection<Token> localTokens = getLocalTokens();
         setGossipTokens(localTokens);
+        tokenMetadata.updateNormalTokens(tokens, FBUtilities.getBroadcastAddress());
         setMode(Mode.NORMAL, false);
     }
 
@@ -431,11 +433,10 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
         // make magic happen
         Gossiper.instance.doShadowRound();
 
-        UUID hostId = null;
         // now that we've gossiped at least once, we should be able to find the node we're replacing
         if (Gossiper.instance.getEndpointStateForEndpoint(DatabaseDescriptor.getReplaceAddress())== null)
             throw new RuntimeException("Cannot replace_address " + DatabaseDescriptor.getReplaceAddress() + " because it doesn't exist in gossip");
-        hostId = Gossiper.instance.getHostId(DatabaseDescriptor.getReplaceAddress());
+        replacingId = Gossiper.instance.getHostId(DatabaseDescriptor.getReplaceAddress());
         try
         {
             VersionedValue tokensVersionedValue = Gossiper.instance.getEndpointStateForEndpoint(DatabaseDescriptor.getReplaceAddress()).getApplicationState(ApplicationState.TOKENS);
@@ -443,7 +444,10 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
                 throw new RuntimeException("Could not find tokens for " + DatabaseDescriptor.getReplaceAddress() + " to replace");
             Collection<Token> tokens = TokenSerializer.deserialize(getPartitioner(), new DataInputStream(new ByteArrayInputStream(tokensVersionedValue.toBytes())));
 
-            SystemKeyspace.setLocalHostId(hostId); // use the replacee's host Id as our own so we receive hints, etc
+            if (isReplacingSameAddress())
+            {
+                SystemKeyspace.setLocalHostId(replacingId); // use the replacee's host Id as our own so we receive hints, etc
+            }
             Gossiper.instance.resetEndpointStateMap(); // clean up since we have what we need
             return tokens;
         }
@@ -472,7 +476,7 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
                 // ignore local node or empty status
                 if (entry.getKey().equals(FBUtilities.getBroadcastAddress()) || entry.getValue().getApplicationState(ApplicationState.STATUS) == null)
                     continue;
-                String[] pieces = entry.getValue().getApplicationState(ApplicationState.STATUS).value.split(VersionedValue.DELIMITER_STR, -1);
+                String[] pieces = splitValue(entry.getValue().getApplicationState(ApplicationState.STATUS));
                 assert (pieces.length > 0);
                 String state = pieces[0];
                 if (state.equals(VersionedValue.STATUS_BOOTSTRAPPING) || state.equals(VersionedValue.STATUS_LEAVING) || state.equals(VersionedValue.STATUS_MOVING))
@@ -681,8 +685,15 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
                 if (!DatabaseDescriptor.isAutoBootstrap())
                     throw new RuntimeException("Trying to replace_address with auto_bootstrap disabled will not work, check your configuration");
                 bootstrapTokens = prepareReplacementInfo();
-                appStates.put(ApplicationState.TOKENS, valueFactory.tokens(bootstrapTokens));
-                appStates.put(ApplicationState.STATUS, valueFactory.hibernate(true));
+                if (isReplacingSameAddress())
+                {
+                    logger.warn("Writes will not be forwarded to this node during replacement because it has the same address as " +
+                                "the node to be replaced ({}). If the previous node has been down for longer than max_hint_window_in_ms, " +
+                                "repair must be run after the replacement process in order to make this node consistent.",
+                                DatabaseDescriptor.getReplaceAddress());
+                    appStates.put(ApplicationState.TOKENS, valueFactory.tokens(bootstrapTokens));
+                    appStates.put(ApplicationState.STATUS, valueFactory.hibernate(true));
+                }
             }
             else if (shouldBootstrap())
             {
@@ -799,7 +810,7 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
             }
             else
             {
-                if (!DatabaseDescriptor.getReplaceAddress().equals(FBUtilities.getBroadcastAddress()))
+                if (!isReplacingSameAddress())
                 {
                     try
                     {
@@ -885,17 +896,14 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
         {
             if (dataAvailable)
             {
-                // start participating in the ring.
-                SystemKeyspace.setBootstrapState(SystemKeyspace.BootstrapState.COMPLETED);
-                setTokens(bootstrapTokens);
+                finishJoiningRing();
+
                 // remove the existing info about the replaced node.
                 if (!current.isEmpty())
                 {
                     for (InetAddress existing : current)
                         Gossiper.instance.replacedEndpoint(existing);
                 }
-                assert tokenMetadata.sortedTokens().size() > 0;
-                doAuthSetup();
             }
             else
             {
@@ -908,6 +916,11 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
         }
     }
 
+    public static boolean isReplacingSameAddress()
+    {
+        return DatabaseDescriptor.getReplaceAddress().equals(FBUtilities.getBroadcastAddress());
+    }
+
     public void gossipSnitchInfo()
     {
         IEndpointSnitch snitch = DatabaseDescriptor.getEndpointSnitch();
@@ -933,16 +946,22 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
         }
         else if (isSurveyMode)
         {
-            setTokens(SystemKeyspace.getSavedTokens());
-            SystemKeyspace.setBootstrapState(SystemKeyspace.BootstrapState.COMPLETED);
             isSurveyMode = false;
             logger.info("Leaving write survey mode and joining ring at operator request");
-            assert tokenMetadata.sortedTokens().size() > 0;
-
-            doAuthSetup();
+            finishJoiningRing();
         }
     }
 
+    private void finishJoiningRing()
+    {
+        // start participating in the ring.
+        SystemKeyspace.setBootstrapState(SystemKeyspace.BootstrapState.COMPLETED);
+        setTokens(bootstrapTokens);
+
+        assert tokenMetadata.sortedTokens().size() > 0;
+        doAuthSetup();
+    }
+
     private void doAuthSetup()
     {
         maybeAddOrUpdateKeyspace(AuthKeyspace.definition());
@@ -1000,7 +1019,7 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
 
     public boolean isJoined()
     {
-        return tokenMetadata.isMember(FBUtilities.getBroadcastAddress());
+        return tokenMetadata.isMember(FBUtilities.getBroadcastAddress()) && !isSurveyMode;
     }
 
     public void rebuild(String sourceDc)
@@ -1122,12 +1141,15 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
     {
         isBootstrapMode = true;
         SystemKeyspace.updateTokens(tokens); // DON'T use setToken, that makes us part of the ring locally which is incorrect until we are done bootstrapping
-        if (!replacing)
+
+        if (!replacing || !isReplacingSameAddress())
         {
             // if not an existing token then bootstrap
             List<Pair<ApplicationState, VersionedValue>> states = new ArrayList<>();
             states.add(Pair.create(ApplicationState.TOKENS, valueFactory.tokens(tokens)));
-            states.add(Pair.create(ApplicationState.STATUS, valueFactory.bootstrapping(tokens)));
+            states.add(Pair.create(ApplicationState.STATUS, replacing?
+                                                            valueFactory.bootReplacing(DatabaseDescriptor.getReplaceAddress()) :
+                                                            valueFactory.bootstrapping(tokens)));
             Gossiper.instance.addLocalApplicationStates(states);
             setMode(Mode.JOINING, "sleeping " + RING_DELAY + " ms for pending range setup", true);
             Uninterruptibles.sleepUninterruptibly(RING_DELAY, TimeUnit.MILLISECONDS);
@@ -1138,6 +1160,7 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
             tokenMetadata.updateNormalTokens(tokens, FBUtilities.getBroadcastAddress());
             SystemKeyspace.removeEndpoint(DatabaseDescriptor.getReplaceAddress());
         }
+
         if (!Gossiper.instance.seenAnySeed())
             throw new IllegalStateException("Unable to contact any seeds!");
 
@@ -1575,14 +1598,16 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
     {
         if (state == ApplicationState.STATUS)
         {
-            String apStateValue = value.value;
-            String[] pieces = apStateValue.split(VersionedValue.DELIMITER_STR, -1);
+            String[] pieces = splitValue(value);
             assert (pieces.length > 0);
 
             String moveName = pieces[0];
 
             switch (moveName)
             {
+                case VersionedValue.STATUS_BOOTSTRAPPING_REPLACE:
+                    handleStateBootreplacing(endpoint, pieces);
+                    break;
                 case VersionedValue.STATUS_BOOTSTRAPPING:
                     handleStateBootstrap(endpoint);
                     break;
@@ -1656,6 +1681,11 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
         }
     }
 
+    private static String[] splitValue(VersionedValue value)
+    {
+        return value.value.split(VersionedValue.DELIMITER_STR, -1);
+    }
+
     public void updateTopology(InetAddress endpoint)
     {
         if (getTokenMetadata().isMember(endpoint))
@@ -1820,6 +1850,43 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
         tokenMetadata.updateHostId(Gossiper.instance.getHostId(endpoint), endpoint);
     }
 
+
+    private void handleStateBootreplacing(InetAddress newNode, String[] pieces)
+    {
+        InetAddress oldNode;
+        try
+        {
+            oldNode = InetAddress.getByName(pieces[1]);
+        }
+        catch (Exception e)
+        {
+            logger.error("Node {} tried to replace malformed endpoint {}.", newNode, pieces[1], e);
+            return;
+        }
+
+        if (FailureDetector.instance.isAlive(oldNode))
+        {
+            throw new RuntimeException(String.format("Node %s is trying to replace alive node %s.", newNode, oldNode));
+        }
+
+        Optional<InetAddress> replacingNode = tokenMetadata.getReplacingNode(newNode);
+        if (replacingNode.isPresent() && !replacingNode.get().equals(oldNode))
+        {
+            throw new RuntimeException(String.format("Node %s is already replacing %s but is trying to replace %s.",
+                                                     newNode, replacingNode.get(), oldNode));
+        }
+
+        Collection<Token> tokens = getTokensFor(newNode);
+
+        if (logger.isDebugEnabled())
+            logger.debug("Node {} is replacing {}, tokens {}", newNode, oldNode, tokens);
+
+        tokenMetadata.addReplaceTokens(tokens, newNode, oldNode);
+        PendingRangeCalculatorService.instance.update();
+
+        tokenMetadata.updateHostId(Gossiper.instance.getHostId(newNode), newNode);
+    }
+
     /**
      * Handle node move to normal state. That is, node is entering token ring and participating
      * in reads.
@@ -1844,11 +1911,31 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
                          endpoint,
                          Gossiper.instance.getEndpointStateForEndpoint(endpoint));
 
+        Optional<InetAddress> replacingNode = tokenMetadata.getReplacingNode(endpoint);
+        if (replacingNode.isPresent())
+        {
+            assert !endpoint.equals(replacingNode.get()) : "Pending replacement endpoint with same address is not supported";
+            logger.info("Node {} will complete replacement of {} for tokens {}", endpoint, replacingNode.get(), tokens);
+            if (FailureDetector.instance.isAlive(replacingNode.get()))
+            {
+                logger.error("Node {} cannot complete replacement of alive node {}.", endpoint, replacingNode.get());
+                return;
+            }
+            endpointsToRemove.add(replacingNode.get());
+        }
+
+        Optional<InetAddress> replacementNode = tokenMetadata.getReplacementNode(endpoint);
+        if (replacementNode.isPresent())
+        {
+            logger.warn("Node {} is currently being replaced by node {}.", endpoint, replacementNode.get());
+        }
+
         updatePeerInfo(endpoint);
         // Order Matters, TM.updateHostID() should be called before TM.updateNormalToken(), (see CASSANDRA-4300).
         UUID hostId = Gossiper.instance.getHostId(endpoint);
         InetAddress existing = tokenMetadata.getEndpointForHostId(hostId);
-        if (replacing && Gossiper.instance.getEndpointStateForEndpoint(DatabaseDescriptor.getReplaceAddress()) != null && (hostId.equals(Gossiper.instance.getHostId(DatabaseDescriptor.getReplaceAddress()))))
+        if (replacing && isReplacingSameAddress() && Gossiper.instance.getEndpointStateForEndpoint(DatabaseDescriptor.getReplaceAddress()) != null
+            && (hostId.equals(Gossiper.instance.getHostId(DatabaseDescriptor.getReplaceAddress()))))
             logger.warn("Not updating token metadata for {} because I am replacing it", endpoint);
         else
         {
@@ -1933,7 +2020,7 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
                 Gossiper.instance.replacementQuarantine(ep); // quarantine locally longer than normally; see CASSANDRA-8260
         }
         if (!tokensToUpdateInSystemKeyspace.isEmpty())
-            SystemKeyspace.updateTokens(endpoint, tokensToUpdateInSystemKeyspace);;
+            SystemKeyspace.updateTokens(endpoint, tokensToUpdateInSystemKeyspace);
 
         if (isMoving || operationMode == Mode.MOVING)
         {
@@ -2058,7 +2145,7 @@ public class StorageService extends NotificationBroadcasterSupport implements IE
                 PendingRangeCalculatorService.instance.update();
 
                 // find the endpoint coordinating this removal that we need to notify when we're done
-                String[] coordinator = Gossiper.instance.getEndpointStateForEndpoint(endpoint).getApplicationState(ApplicationState.REMOVAL_COORDINATOR).value.split(VersionedValue.DELIMITER_STR, -1);
+                String[] coordinator = splitValue(Gossiper.instance.getEndpointStateForEndpoint(endpoint).getApplicationState(ApplicationState.REMOVAL_COORDINATOR));
                 UUID hostId = UUID.fromString(coordinator[1]);
                 // grab any data we are now responsible for and notify responsible node
                 restoreReplicaCount(endpoint, tokenMetadata.getEndpointForHostId(hostId));