问题
I have a single server cluster installation of MemSQL on Ubuntu 14 LTS. I am unable to connect to memsql on port 3306 but the cluster is running on port 9000. Looks like a leaf is down. When i tried to upgrade memsql to version 4.0.1 I got this error:-
Starting MemSQL Upgrade
Currently on state OfflineClusterUpgrade.Init
Currently on state OfflineClusterUpgrade.SnapshottingDatabases
Currently on state OfflineClusterUpgrade.OfflineClusterUpgradeFail
MemSQL node 8D84F89D6716F03A44EACB9E3AF6565FA76B9DE9 failed to upgrade: Could not connect to MemSQL node 8D84F89D6716F03A44EACB9E3AF6565FA76B9DE9. Is the MemSQL node online?
What can I do to bring MemSql up again?
回答1:
The cluster manager provided the help on port 9000. Firstly it clearly showed the status of all nodes.
There was an alert icon clicking it showed the solution.
I ran the command
memsql-ops cluster-start
It caused the node to recover and start again. This is really good.
来源：https://stackoverflow.com/questions/31423480/memsql-leaf-down-on-single-server-cluster