@Override
    public boolean checkMasterStatus() throws IllegalStateException {
        if (masterFlag) {
            try {
                jdbcLockRegistry.renewLock(MASTER_LOCK_KEY);
            } catch (IllegalStateException e) {
                masterFlag = false;
                throw e;
            }
        }
        return masterFlag;
    }
The cluster select master service jdbc impl.
shenyu-admin/src/main/java/org/apache/shenyu/admin/mode/cluster/impl/jdbc/ClusterSelectMasterServiceJdbcImpl.java