lightdb WARNING: could not establish connection after 30000 ms

 看issue https://github.com/citusdata/citus/discussions/7206应该是网络不通，但是连接本地节点，那唯一的可能应该就是被kill或者工作节点挂了。模拟参见：https://blog.csdn.net/fm0517/article/details/79397826