public void lostDatabaseConnection() {
        verifyInControllerThread();
        boolean wasMaster = isMaster;
        masterElectionHandler.lostDatabaseConnection();
        if (wasMaster) {
            // Enforce that we re-fetch all state information from ZooKeeper upon the next tick if we're still master.
            dropLeadershipState();
            metricUpdater.updateMasterState(false);
        }
    }
Called when we can no longer contact database.
clustercontroller-core/src/main/java/com/yahoo/vespa/clustercontroller/core/FleetController.java