@Override
    public boolean selectMaster() {
        masterFlag = clusterMasterLock.tryLock();
        LOG.info("select master result: {}", masterFlag);
        return masterFlag;
    }
The cluster select master service jdbc impl.
shenyu-admin/src/main/java/org/apache/shenyu/admin/mode/cluster/impl/jdbc/ClusterSelectMasterServiceJdbcImpl.java