We cannot remove a '(MISSING)' instance under Multi-Primary mode.

[佳晃 富田]

Hello,

We are using MySQL InnoDB Cluster(version 8.0.18).
We are trying to remove a '(MISSING)' instance under Multi-Primary mode,but we cannot.


①
This is the current cluster's status.
Instance '172.18.0.31:3306' has a status '(MISSING)'.

----------------------------------------------------------------------------------------------
MySQL 172.18.0.33:33060+ ssl JS > cluster.status()
{
"clusterName": "qkdb_cluster",
"defaultReplicaSet": {
"name": "default",
"ssl": "REQUIRED",
"status": "OK_NO_TOLERANCE",
"statusText": "Cluster is NOT tolerant to any failures. 1 member is not active",
"topology": {
"172.18.0.31:3306": {
"address": "172.18.0.31:3306",
"mode": "R/W",
"readReplicas": {},
"role": "HA",
"status": "(MISSING)"
},
"172.18.0.32:3306": {
"address": "172.18.0.32:3306",
"mode": "R/W",
"readReplicas": {},
"replicationLag": null,
"role": "HA",
"status": "ONLINE",
"version": "8.0.18"
},
"172.18.0.33:3306": {
"address": "172.18.0.33:3306",
"mode": "R/W",
"readReplicas": {},
"replicationLag": null,
"role": "HA",
"status": "ONLINE",
"version": "8.0.18"
}
},
"topologyMode": "Multi-Primary"
},
"groupInformationSourceMember": "172.18.0.33:3306"
}
----------------------------------------------------------------------------------------------


②
We would like to force remove instance '172.18.0.31:3306', but some error messages are shown as below.

----------------------------------------------------------------------------------------------
MySQL 172.18.0.33:33060+ ssl JS > cluster.removeInstance('172.18.0.31:3306',{force:true})
The instance will be removed from the InnoDB cluster. Depending on the instance
being the Seed or not, the Metadata session might become invalid. If so, please
start a new session to the Metadata Storage R/W instance.

NOTE: The recovery user name for instance '172.18.0.31:3306' does not match the expected format for users created automatically by InnoDB Cluster. Skipping its removal.
Cluster.removeInstance: The table does not comply with the requirements by an external plugin. (MySQL Error 3098)
----------------------------------------------------------------------------------------------

How can we force remove the '(MISSING)' instance ?
Please give us some advice.