ZooKeeper is always used, simplify

4 files changed, 19 insertions, 61 deletions

diff --git a/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/FleetController.java b/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/FleetController.java
index 01e9a173d64..d996253627f 100644
--- a/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/FleetController.java
+++ b/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/FleetController.java
@@ -488,7 +488,6 @@ public class FleetController implements NodeListener, SlobrokListener, SystemSta
 
         masterElectionHandler.setFleetControllerCount(options.fleetControllerCount());
         masterElectionHandler.setMasterZooKeeperCooldownPeriod(options.masterZooKeeperCooldownPeriod());
-        masterElectionHandler.setUsingZooKeeper(options.zooKeeperServerAddress() != null && !options.zooKeeperServerAddress().isEmpty());
 
         if (rpcServer != null) {
             rpcServer.setMasterElectionHandler(masterElectionHandler);
@@ -560,7 +559,7 @@ public class FleetController implements NodeListener, SlobrokListener, SystemSta
 
             if ( ! isRunning()) { return; }
 
-            if (masterElectionHandler.isFirstInLine()) {
+            if (masterElectionHandler.isFirstInLine() || options.fleetControllerCount() == 1) {
                 didWork |= resyncLocallyCachedState(); // Calls to metricUpdate.forWork inside method
             } else {
                 stepDownAsStateGatherer();
diff --git a/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/MasterElectionHandler.java b/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/MasterElectionHandler.java
index fa303533355..df95b4c8fe5 100644
--- a/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/MasterElectionHandler.java
+++ b/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/MasterElectionHandler.java
@@ -26,7 +26,6 @@ public class MasterElectionHandler implements MasterInterface {
     private Map<Integer, Integer> nextMasterData;
     private long masterGoneFromZooKeeperTime; // Set to time master fleet controller disappears from zookeeper
     private long masterZooKeeperCooldownPeriod; // The period in ms that we won't take over unless master come back.
-    private boolean usingZooKeeper = false; // Unit tests may not use ZooKeeper at all.
 
     public MasterElectionHandler(FleetControllerContext context, int index, int totalCount, Object monitor, Timer timer) {
         this.context = context;
@@ -43,25 +42,12 @@ public class MasterElectionHandler implements MasterInterface {
 
     public void setFleetControllerCount(int count) {
         totalCount = count;
-        if (count == 1 && !usingZooKeeper) {
-            masterCandidate = 0;
-            followers = 1;
-            nextInLineCount = 0;
-        }
     }
 
     public void setMasterZooKeeperCooldownPeriod(int period) {
         masterZooKeeperCooldownPeriod = period;
     }
 
-    public void setUsingZooKeeper(boolean usingZK) {
-        if (!usingZooKeeper && usingZK) {
-            // Reset any shortcuts taken by non-ZK election logic.
-            resetElectionProgress();
-        }
-        usingZooKeeper = usingZK;
-    }
-
     @Override
     public boolean isMaster() {
         Integer master = getMaster();
@@ -121,15 +107,13 @@ public class MasterElectionHandler implements MasterInterface {
     public boolean isFirstInLine() { return (nextInLineCount < 1); }
 
     public boolean watchMasterElection(DatabaseHandler database, DatabaseHandler.DatabaseContext dbContext) {
-        if (totalCount == 1 && !usingZooKeeper) {
-            return false; // Allow single configured node to become master implicitly if no ZK configured
-        }
         if (nextMasterData == null) {
             if (masterCandidate == null) {
                 context.log(logger, Level.FINEST, () -> "No current master candidate. Waiting for data to do master election.");
             }
             return false; // Nothing have happened since last time.
         }
+
         // Move next data to temporary, such that we don't need to keep lock, and such that we don't retry
         // if we happen to fail processing the data.
         Map<Integer, Integer> state;
@@ -140,6 +124,7 @@ public class MasterElectionHandler implements MasterInterface {
         }
         context.log(logger, Level.INFO, "Got master election state " + toString(state) + ".");
         if (state.isEmpty()) throw new IllegalStateException("Database has no master data. We should at least have data for ourselves.");
+
         Map.Entry<Integer, Integer> first = state.entrySet().iterator().next();
         Integer currentMaster = getMaster();
         if (currentMaster != null && first.getKey().intValue() != currentMaster.intValue()) {
@@ -238,10 +223,8 @@ public class MasterElectionHandler implements MasterInterface {
     }
 
     public void lostDatabaseConnection() {
-        if (totalCount > 1 || usingZooKeeper) {
-            context.log(logger, Level.INFO, "Clearing master data as we lost connection on node " + index);
-            resetElectionProgress();
-        }
+        context.log(logger, Level.INFO, "Clearing master data as we lost connection on node " + index);
+        resetElectionProgress();
     }
 
     private void resetElectionProgress() {
diff --git a/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/database/DatabaseHandler.java b/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/database/DatabaseHandler.java
index efb97a4a69e..ed194776d78 100644
--- a/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/database/DatabaseHandler.java
+++ b/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/database/DatabaseHandler.java
@@ -15,6 +15,7 @@ import org.apache.zookeeper.KeeperException;
 import java.io.PrintWriter;
 import java.io.StringWriter;
 import java.util.Map;
+import java.util.Objects;
 import java.util.TreeMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -101,8 +102,7 @@ public class DatabaseHandler {
         this.timer = timer;
         pendingStore.masterVote = fleetControllerContext.id().index(); // To begin with we'll vote for ourselves.
         this.monitor = monitor;
-        // TODO: Require non-null, not possible now since at least ClusterFeedBlockTest uses null address
-        this.zooKeeperAddress = zooKeeperAddress;
+        this.zooKeeperAddress = Objects.requireNonNull(zooKeeperAddress, "zooKeeperAddress cannot be null");
     }
 
     private boolean isDatabaseClosedSafe() {
@@ -161,11 +161,9 @@ public class DatabaseHandler {
     }
 
     public void setZooKeeperAddress(String address, DatabaseContext databaseContext) {
-        if (address == null && zooKeeperAddress == null) return;
-        if (address != null && address.equals(zooKeeperAddress)) return;
-        if (zooKeeperAddress != null) {
-            fleetControllerContext.log(logger, Level.INFO, "" + (address == null ? "Stopped using ZooKeeper." : "Got new ZooKeeper address to use: " + address));
-        }
+        Objects.requireNonNull(address, "address cannot be null");
+        if (address.equals(zooKeeperAddress)) return;
+        fleetControllerContext.log(logger, Level.INFO, "Got new ZooKeeper address to use: " + address);
         zooKeeperAddress = address;
         reset(databaseContext);
     }
@@ -177,8 +175,6 @@ public class DatabaseHandler {
         reset(databaseContext);
     }
 
-    private boolean usingZooKeeper() { return (zooKeeperAddress != null); }
-
     private void connect(long currentTime) {
         try {
             lastZooKeeperConnectionAttempt = currentTime;
@@ -245,7 +241,7 @@ public class DatabaseHandler {
                 didWork = true;
             }
         }
-        if (isDatabaseClosedSafe() && zooKeeperIsConfigured()) {
+        if (isDatabaseClosedSafe()) {
             long currentTime = timer.getCurrentTimeInMillis();
             if (currentTime - lastZooKeeperConnectionAttempt < minimumWaitBetweenFailedConnectionAttempts) {
                 return false; // Not time to attempt connection yet.
@@ -270,11 +266,6 @@ public class DatabaseHandler {
         return didWork;
     }
 
-    private boolean zooKeeperIsConfigured() {
-        // This should only ever be null during unit testing.
-        return zooKeeperAddress != null;
-    }
-
     private void relinquishDatabaseConnectivity(DatabaseContext databaseContext) {
         // reset() will handle both session clearing and trigger a database loss callback into the CC.
         reset(databaseContext);
@@ -383,9 +374,7 @@ public class DatabaseHandler {
         }
         Integer version = currentlyStored.lastSystemStateVersion;
         if (version == null) {
-            if (usingZooKeeper()) {
-                fleetControllerContext.log(logger, Level.WARNING, "Failed to retrieve latest system state version from ZooKeeper. Returning version 0.");
-            }
+            fleetControllerContext.log(logger, Level.WARNING, "Failed to retrieve latest system state version from ZooKeeper. Returning version 0.");
             return 0; // FIXME "fail-oblivious" is not a good error handling mode for such a critical component!
         }
         return version;
@@ -395,22 +384,13 @@ public class DatabaseHandler {
         fleetControllerContext.log(logger, Level.FINE, () -> "Scheduling bundle " + clusterStateBundle + " to be saved to ZooKeeper");
         pendingStore.clusterStateBundle = clusterStateBundle;
         doNextZooKeeperTask(databaseContext);
-        // FIXME this is a nasty hack to get around the fact that a massive amount of unit tests
-        // set up the system with a null ZooKeeper server address. If we don't fake that we have
-        // written the state version, the tests will never progress past waiting for state broadcasts.
-        if (zooKeeperAddress == null) {
-            logger.warning(() -> "Simulating ZK write of version " + clusterStateBundle.getVersion() + 
-                                 ". This should not happen in production!");
-            lastKnownStateBundleVersionWrittenBySelf = clusterStateBundle.getVersion();
-        }
     }
 
     // TODO should we expand this to cover _any_ pending ZK write?
     public boolean hasPendingClusterStateMetaDataStore() {
         synchronized (databaseMonitor) {
-            return ((zooKeeperAddress != null) &&
-                    ((pendingStore.clusterStateBundle != null) ||
-                     (pendingStore.lastSystemStateVersion != null)));
+            return ((pendingStore.clusterStateBundle != null) ||
+                    (pendingStore.lastSystemStateVersion != null));
         }
     }
 
@@ -458,11 +438,9 @@ public class DatabaseHandler {
         }
         Map<Node, NodeState> wantedStates = currentlyStored.wantedStates;
         if (wantedStates == null) {
-            if (usingZooKeeper()) {
-                // We get here if the ZooKeeper client has lost the connection to ZooKeeper.
-                // TODO: Should instead fail the tick until connected!?
-                fleetControllerContext.log(logger, Level.FINE, () -> "Failed to retrieve wanted states from ZooKeeper. Assuming UP for all nodes.");
-            }
+            // We get here if the ZooKeeper client has lost connection to ZooKeeper.
+            // TODO: Should instead fail the tick until connected!?
+            fleetControllerContext.log(logger, Level.FINE, () -> "Failed to retrieve wanted states from ZooKeeper. Assuming UP for all nodes.");
             wantedStates = new TreeMap<>();
         }
         boolean altered = false;
@@ -510,9 +488,7 @@ public class DatabaseHandler {
         }
         Map<Node, Long> startTimestamps = currentlyStored.startTimestamps;
         if (startTimestamps == null) {
-            if (usingZooKeeper()) {
-                fleetControllerContext.log(logger, Level.WARNING, "Failed to retrieve start timestamps from ZooKeeper. Cluster state will be bloated with timestamps until we get them set.");
-            }
+            fleetControllerContext.log(logger, Level.WARNING, "Failed to retrieve start timestamps from ZooKeeper. Cluster state will be bloated with timestamps until we get them set.");
             startTimestamps = new TreeMap<>();
         }
         for (Map.Entry<Node, Long> e : startTimestamps.entrySet()) {
diff --git a/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/status/LegacyIndexPageRequestHandler.java b/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/status/LegacyIndexPageRequestHandler.java
index 5aae401e157..7a9bea91b9c 100644
--- a/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/status/LegacyIndexPageRequestHandler.java
+++ b/clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/status/LegacyIndexPageRequestHandler.java
@@ -228,7 +228,7 @@ public class LegacyIndexPageRequestHandler implements StatusPageServer.RequestHa
         sb.append("<tr><td><nobr>RPC port</nobr></td><td align=\"right\">").append(options.rpcPort() == 0 ? "Pick random available" : options.rpcPort()).append("</td></tr>");
         sb.append("<tr><td><nobr>HTTP port</nobr></td><td align=\"right\">").append(options.httpPort() == 0 ? "Pick random available" : options.httpPort()).append("</td></tr>");
         sb.append("<tr><td><nobr>Master cooldown period</nobr></td><td align=\"right\">").append(RealTimer.printDuration(options.masterZooKeeperCooldownPeriod())).append("</td></tr>");
-        String zooKeeperAddress = (options.zooKeeperServerAddress() == null ? "Not using Zookeeper" : splitZooKeeperAddress(options.zooKeeperServerAddress()));
+        String zooKeeperAddress = splitZooKeeperAddress(options.zooKeeperServerAddress());
         sb.append("<tr><td><nobr>Zookeeper server address</nobr></td><td align=\"right\">").append(zooKeeperAddress).append("</td></tr>");
         sb.append("<tr><td><nobr>Zookeeper session timeout</nobr></td><td align=\"right\">").append(RealTimer.printDuration(options.zooKeeperSessionTimeout())).append("</td></tr>");