This account is used to create and configure the member servers of an InnoDB Cluster and InnoDB ClusterSet deployment. Each member server has only one server configuration account. The same user account name and password must be used on every member server in the cluster. You can use the root account on the servers for this purpose, but if you do this, the root account on every member server in the cluster must have the same password. This is not recommended for security reasons.

The preferred approach is to create the InnoDB Cluster server configuration account using a dba.configureInstance() command with the clusterAdmin option. For better security, specify the password at the interactive prompt, otherwise specify it using the clusterAdminPassword option. Create the same account, with the same user name and password, in the same way on every server instance that will be part of the InnoDB Cluster - both the instance to which you connect to create the cluster, and the instances that will join the cluster after that.

The dba.configureInstance() command grants the account the required permissions automatically. You may set up the account manually if you prefer, granting it the permissions listed in Configuring InnoDB Cluster Administrator Accounts Manually. The account needs full read and write privileges on the InnoDB Cluster metadata tables, in addition to full MySQL administrator privileges.

The InnoDB Cluster server configuration account that you create using the dba.configureInstance() operation is not replicated to other servers in the InnoDB Cluster or in the InnoDB ClusterSet deployment. MySQL Shell disables binary logging for the dba.configureInstance() operation. This means that you must create the account on every server instance individually.

In an InnoDB ClusterSet deployment, the same InnoDB Cluster server configuration account must exist on every server instance that is used in the deployment. When you set up a replica cluster, you therefore need to issue a dba.configureInstance() command with the clusterAdmin option to create the account on every server instance that is going to be part of the replica cluster. The command must name the InnoDB Cluster server configuration account from the primary cluster, and you must specify the same password for it. You need to do this step before joining the instances into the replica cluster, so the account is available to configure the replica InnoDB Cluster and the InnoDB ClusterSet deployment metadata and replication.

These accounts can be used to administer InnoDB Cluster and InnoDB ClusterSet after you have completed the configuration process. You can set up more than one of them. Each account must exist on every member server in an InnoDB Cluster with the same user name and password, and on every member server of every cluster in an InnoDB ClusterSet deployment.

To create an InnoDB Cluster administrator account for an InnoDB ClusterSet deployment, you issue a cluster.setupAdminAccount() command on one member server in the primary cluster, after you have added all the instances to that cluster. This command creates an account with the user name and password that you specify, with all the required permissions. A transaction to create an account with cluster.setupAdminAccount() is sent to all the other server instances in the cluster to create the account on them.

If the primary InnoDB Cluster already existed when you began to set up the InnoDB ClusterSet deployment, an InnoDB Cluster administrator account likely already exists. In that case, you do not need to issue cluster.setupAdminAccount() again, unless you want to create further InnoDB Cluster administrator accounts.

The replica clusters in an InnoDB ClusterSet deployment must have the same set of InnoDB Cluster administrator accounts as the primary cluster. However, when you create the replica clusters, do not attempt to set up the InnoDB Cluster administrator accounts yourself. The transactions to create accounts with cluster.setupAdminAccount() are written to the binary log for the primary cluster, and they are automatically replicated from the primary cluster to the replica clusters during the provisioning process. When a replica cluster applies these transactions it creates the same accounts on the member servers in the replica cluster. If the accounts already exist on a server in the replica cluster, this causes a replication error, and the server cannot join the cluster. So you need to wait for them to be replicated.

If a transaction to create an InnoDB Cluster administrator account happened a while back on the primary cluster, it might take some time for the transaction to be replicated and for the account to appear on a replica cluster. Selecting cloning as the provisioning method for the replica cluster speeds up the process.

When the InnoDB ClusterSet deployment is complete, you may use cluster.setupAdminAccount() to create further InnoDB Cluster administrator accounts for the ClusterSet. You can do this while connected to any member server in the InnoDB ClusterSet deployment, either in the primary cluster or in a replica cluster. The transaction to create the account is routed to the primary cluster to be executed, then replicated to all the servers in the replica clusters, where it creates the account on all of them.

These accounts are used by MySQL Router to connect to server instances in an InnoDB Cluster and in an InnoDB ClusterSet deployment. You can set up more than one of them. Each account must exist on every member server in an InnoDB Cluster with the same user name and password, or SSL certificate, and on every member server of every cluster in an InnoDB ClusterSet deployment.

The process to create a MySQL Router account is the same as for an InnoDB Cluster administrator account, but using a cluster.setupRouterAccount() command. You create the accounts on one member server in the primary cluster, or use accounts that already exist, if the primary InnoDB Cluster already existed when you began to set up the InnoDB ClusterSet deployment. Then let the replica clusters apply the transactions to create the accounts on their member servers. For instructions to create or upgrade a MySQL Router account, see Section 7.2, “Configuring the MySQL Router User”.