protected void notifyWatchers(List<RemoteInstance> remoteInstances) {
        if (log.isDebugEnabled()) {
            log.debug("Notify watchers and update cluster instances:{}", remoteInstances.toString());
        }
        this.clusterWatchers.forEach(
            clusterWatcher -> clusterWatcher.onClusterNodesChanged(remoteInstances));
    }
Initialize the required resources, such as healthy checker and listener.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/cluster/ClusterCoordinator.java