MySQL Shell 8.4
Once you have prepared your instances, use the
dba.createCluster() function to create the
cluster, using the instance which MySQL Shell is connected to
as the seed instance for the cluster. The seed instance is
replicated to the other instances that you add to the cluster,
making them replicas of the seed instance. In this procedure the
ic-1 instance is used as the seed. When you issue
dba.createCluster(
MySQL Shell creates a classic MySQL protocol session to the server
instance connected to the MySQL Shell's current global session.
For example, to create a cluster called
name)testCluster and assign the returned
cluster to a variable called cluster:
mysql-js> var cluster = dba.createCluster('testCluster')
Validating instance at icadmin@ic-1:3306...
This instance reports its own address as ic-1
Instance configuration is suitable.
Creating InnoDB cluster 'testCluster' on 'icadmin@ic-1:3306'...
Adding Seed Instance...
Cluster successfully created. Use Cluster.addInstance() to add MySQL instances.
At least 3 instances are needed for the cluster to be able to withstand up to
one server failure.
The Cluster's name must be non-empty and no greater than 63 characters long. It can only start with an alphanumeric character or with _ (underscore), and can only contain alphanumeric, _ ( underscore), . (period), or - (hyphen) characters.
This pattern of assigning the returned cluster to a variable enables you to then execute further operations against the cluster using the Cluster object's methods. The returned Cluster object uses a new session, independent from the MySQL Shell's global session. This ensures that if you change the MySQL Shell global session, the Cluster object maintains its session to the instance.
To be able to administer a cluster, you must ensure that you
have a suitable user which has the required privileges. The
recommended approach is to create an administration user. If you
did not create an administration user when configuring your
instances, use the
Cluster.setupAdminAccount()icadmin that can administer the
InnoDB Cluster assigned to the variable
cluster, issue:
mysql-js> cluster.setupAdminAccount("icadmin")
See Configuring InnoDB Cluster Administrator Accounts Manually for more information on InnoDB Cluster administrator accounts.
When you run dba.createCluster(), and when
you add a further server instance to the InnoDB Cluster by
running
Cluster.addInstance()
2020-02-10T10:53:43.727246Z 12 [ERROR] [MY-011685] [Repl] Plugin group_replication reported: 'The group name option is mandatory' 2020-02-10T10:53:43.727292Z 12 [ERROR] [MY-011660] [Repl] Plugin group_replication reported: 'Unable to start Group Replication on boot'
If you encounter an error related to metadata being inaccessible you might have the loopback network interface configured. For correct InnoDB Cluster usage disable the loopback interface.
To check the cluster has been created, use the cluster
instance's status() function. See
Checking a cluster's Status with
Cluster.status()
Once server instances belong to a cluster it is important to
only administer them using MySQL Shell and AdminAPI.
Attempting to manually change the configuration of Group
Replication on an instance once it has been added to a cluster
is not supported. Similarly, modifying server variables
critical to InnoDB Cluster, such as
server_uuid, after an
instance is configured using AdminAPI is not supported.
When you create a cluster using MySQL Shell, you can set the
amount of time to wait before instances are expelled from the
cluster, for example when they become unreachable. Pass the
expelTimeout option to the
dba.createCluster() operation, which
configures the
group_replication_member_expel_timeout
variable on the seed instance. The
expelTimeout option can take an integer value
in the range of 0 to 3600. All instances running MySQL server
8.0.13 and later which are added to a cluster with
expelTimeout configured are automatically
configured to have the same expelTimeout
value as configured on the seed instance.
For information on the other options which you can pass to
dba.createCluster(), see
Section 7.9, “Modifying or Dissolving an InnoDB Cluster”.
It is possible to enable or disable
group_replication_paxos_single_leader
using dba.createCluster().
This can only be set by MySQL Shell on MySQL Server 8.0.31,
or higher, because MySQL Shell requires the information
provided by
WRITE_CONSENSUS_SINGLE_LEADER_CAPABLE in
the
replication_group_communication_information
table, which was introduced in MySQL 8.0.31.
When you create a cluster, if you have security requirements
that all accounts created automatically by AdminAPI have
strict authentication requirements, you can set a value for
the replicationAllowedHost cluster
configuration option. The
replicationAllowedHost option means that
all accounts created automatically can only connect from
allowed hosts, using strict subnet-based filtering.
Previously, the
Internal User Accounts Created by InnoDB Cluster, by
default, were accessible from anywhere.
The replicationAllowedHost option can take
a string value. For example, to create a cluster called
testCluster and set the
replicationAllowedHost option to
192.0.2.0/24, issue:
mysql-js> dba.createCluster('testCluster', {replicationAllowedHost:'192.0.2.0/24'})
InnoDB Cluster supports the MySQL communication stack introduced for Group Replication in MySQL 8.0.27.
The option, communicationStack: XCOM|MYSQL
sets the value of the Group Replication system variable
group_replication_communication_stack.
For example:
mysql-js> dba.createCluster("testCluster", {communicationStack: "xcom"})
The MYSQL communication stack is the
default for all new clusters created for MySQL 8.0.27, or
higher.
For more information, see Section 7.5.9, “Configuring the Group Replication Communication Stack”.