6.10.7 Working with a Cluster's Routers

You can bootstrap multiple instances of MySQL Router against InnoDB Cluster or InnoDB ReplicaSet. To show a list of all registered MySQL Router instances, issue:

Cluster.listRouters()

The result provides information about each registered MySQL Router instance, such as its name in the metadata, the hostname, ports, and so on. For example, issue the following JavaScript command:

mysql-js> Cluster.listRouters()
{
    "clusterName": "example",
    "routers": {
        "ic-1:3306": {
            "hostname": "ic-1:3306",
            "lastCheckIn": "2020-01-16 11:43:45",
            "roPort": 6447,
            "roXPort": 64470,
            "rwPort": 6446,
            "rwXPort": 64460,
            "version": "8.0.19"
        }
    }
}

Or issue the following Python command:

mysql-py> Cluster.list_routers()
{
    "clusterName": "example",
    "routers": {
        "ic-1:3306": {
            "hostname": "ic-1:3306",
            "lastCheckIn": "2020-01-16 11:43:45",
            "roPort": 6447,
            "roXPort": 64470,
            "rwPort": 6446,
            "rwXPort": 64460,
            "rwSplitPort": 6450,
            "version": "8.0.19"
        }
    }
}

The returned information shows:

• The name of the MySQL Router instance.

• Last check-in timestamp, which is generated by a periodic ping from the MySQL Router stored in the metadata.

• Hostname where the MySQL Router instance is running.

• Read-Only (roPort) and Read-Write (rwPort) ports, which the MySQL Router publishes for classic MySQL protocol connections.

• Read-Only (roXPort) and Read-Write (rwXPort) ports, which the MySQL Router publishes for X Protocol connections.

• Read-Write splitting (rwSplitPort) ports, which the MySQL Router publishes for split classic MySQL protocol connections.

  See Read/Write Splitting.

• Version of this MySQL Router instance. If this operation is run against an version of MySQL Router earlier than 8.0.19, the version field is null.

Additionally, the Cluster.listRouters() operation can show a list of instances that do not support the metadata version supported by MySQL Shell. Use the onlyUpgradeRequired option. For example, by issuing Cluster.listRouters({'onlyUpgradeRequired':'true'}).

The returned list shows only the MySQL Router instances registered with the Cluster, which require an upgrade of their metadata. For more information, see Section 6.11, “Upgrade Metadata Schema”.

MySQL Router instances are not automatically removed from the metadata, so for example as you bootstrap more instances the InnoDB Cluster metadata contains a growing number of references to instances. To remove a registered MySQL Router instance from a cluster's metadata, use the Cluster.removeRouterMetadata(router) operation.

Use the Cluster.listRouters() operation to get the name of the MySQL Router instance you want to remove, and pass it in as router. For example, suppose the MySQL Router instances registered with a cluster were:

mysql-js> Cluster.listRouters(){

    "clusterName": "testCluster",
    "routers": {
        "myRouter1": {
            "hostname": "example1.com",
            "lastCheckIn": null,
            "routerId": "1",
            "roPort": "6447",
            "rwPort": "6446"
            "version": null
        },
        "myRouter2": {
            "hostname": "example2.com",
            "lastCheckIn": "2019-11-27 16:25:00",
            "routerId": "3",
            "roPort": "6447",
            "rwPort": "6446"
            "version": "8.0.19"
        }
    }
}

Based on the fact that the instance named “myRouter1” has null for “lastCheckIn” and “version”. Remove this old instance from the metadata by issuing the following JavaScript command:

mysql-js> cluster.removeRouterMetadata('myRouter1')

Or, by issuing the following Python command:

mysql-py> cluster.remove_router_metadata('myRouter1')

The MySQL Router instance specified is unregistered from the cluster by removing it from the InnoDB Cluster metadata.