扩展计算节点时偶遇 gpexpand --rollback问题

场景：

(1)在使用gpexpand -i config_file文件时,遇到如下错误信息，并伴随整个集群服务全部启停止

20161111:09:44:36:005874 gpstart:ETL:gpadmin-[ERROR]:-gpstart error: Found a System Expansion Setup in progress. Please run 'gpexpand --rollback'

(2)在此过程中尝试使用gpexpand --rollback时，由于集群服务已经停止的原因，所以使用此命令也是无效的

20161111:09:44:49:005951 gpexpand:ETL:gpadmin-[INFO]:-local Greenplum Version: 'postgres (Greenplum Database) 4.3.8.0 build 1'

20161111:09:44:49:005951 gpexpand:ETL:gpadmin-[ERROR]:-gpexpand failed: could not connect to server: Connection refused

        Is the server running on host "localhost" (::1) and accepting

        TCP/IP connections on port 5432?

could not connect to server: Connection refused

        Is the server running on host "localhost" (127.0.0.1) and accepting

        TCP/IP connections on port 5432?

(3) 尝试使用gpstart -a 命令重新启动集群，但是由于扩展节点的失败，又报如下错误

20161111:09:44:36:005874 gpstart:ETL:gpadmin-[ERROR]:-gpstart error: Found a System Expansion Setup in progress. Please run 'gpexpand --rollback

(4) 尝试使用gpstart -m试着只启动master节点，发现确实可行。

(5)启动master成功后，再次执行gpexpand --rollback命令，确实可行。回滚完成后，再次重新启动集群，又恢复到了之前的状态。