ClusterSet Class Reference

Represents an InnoDB ClusterSet. More...

Methods
str	get_name ()
	Returns the domain name of the clusterset. More...
None	disconnect ()
	Disconnects all internal sessions used by the ClusterSet object. More...
Cluster	create_replica_cluster (InstanceDef instance, str clusterName, dict options)
	Creates a new InnoDB Cluster that is a Replica of the Primary Cluster. More...
None	remove_cluster (str clusterName, dict options)
	Removes a Replica cluster from a ClusterSet. More...
None	rejoin_cluster (str clusterName, dict options)
	Rejoin an invalidated Cluster back to the ClusterSet and update replication. More...
None	set_primary_cluster (str clusterName, dict options)
	Performs a safe switchover of the PRIMARY Cluster of the ClusterSet. More...
None	force_primary_cluster (str clusterName, dict options)
	Performs a failover of the PRIMARY Cluster of the ClusterSet. More...
dict	status (dict options)
	Describe the status of the ClusterSet. More...
dict	describe ()
	Describe the structure of the ClusterSet. More...
None	dissolve (dict options)
	Dissolves the ClusterSet. More...
None	set_routing_option (str router, str option, str value)
	Changes the value of either a global Routing option or of a single Router instance. More...
None	setup_admin_account (str user, dict options)
	Create or upgrade an InnoDB ClusterSet admin account. More...
None	setup_router_account (str user, dict options)
	Create or upgrade a MySQL account to use with MySQL Router. More...
dict	routing_options (str router)
	Lists the ClusterSet Routers configuration options. More...
dict	list_routers (str router)
	Lists the Router instances of the ClusterSet, or a single Router instance. More...
None	set_option (str option, str value)
	Changes the value of an option for the whole ClusterSet. More...
dict	options ()
	Lists the ClusterSet configuration options. More...
dict	execute (str cmd, object instances, dict options)
	Executes a SQL statement at selected instances of the ClusterSet. More...

Properties
str	name
	Returns the domain name of the clusterset.

Detailed Description

Represents an InnoDB ClusterSet.

The clusterset object is the entry point to manage and monitor a MySQL InnoDB ClusterSet.

ClusterSets allow InnoDB Cluster deployments to achieve fault-tolerance at a whole Data Center / region or geographic location, by creating REPLICA clusters in different locations (Data Centers), ensuring Disaster Recovery is possible.

For more help on a specific function, use the \help shell command, e.g.: \help ClusterSet.create_replica_cluster

Member Function Documentation

get_name()

str get_name

(

)

Returns the domain name of the clusterset.

Returns

domain name of the clusterset.

disconnect()

void disconnect

(

)

Disconnects all internal sessions used by the ClusterSet object.

Returns

Nothing.

Disconnects the internal MySQL sessions used by the ClusterSet to query for metadata and replication information.

create_replica_cluster()

Cluster create_replica_cluster	(	InstanceDef	instance,
		str	clusterName,
		dict	options
	)

Creates a new InnoDB Cluster that is a Replica of the Primary Cluster.

Parameters

instance	host:port of the target instance to be used to create the Replica Cluster
clusterName	An identifier for the REPLICA cluster to be created.
options	optional Dictionary with additional parameters described below.

Returns

The created Replica Cluster object.

Creates a REPLICA InnoDB cluster of the current PRIMARY cluster with the given cluster name and options, at the target instance.

If the target instance meets the requirements for InnoDB Cluster a new cluster is created on it, replicating from the PRIMARY instance of the primary cluster of the ClusterSet.

Pre-requisites

The following is a list of requirements to create a REPLICA cluster:

• The target instance must comply with the requirements for InnoDB Cluster.
• The target instance must be a standalone instance.
• The target instance must running MySQL 8.0.27 or newer.
• Unmanaged replication channels are not allowed.
• The target instance 'server_id' and 'server_uuid' must be unique in the ClusterSet
• The target instance must have the same credentials used to manage the ClusterSet.

The Replica 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.

For the detailed list of requirements to create an InnoDB Cluster, please use \? createCluster

Options

The options dictionary can contain the following values:

• dryRun: boolean if true, all validations and steps for creating a Replica Cluster are executed, but no changes are actually made. An exception will be thrown when finished.
• recoveryMethod: Preferred method for state recovery/provisioning. May be auto, clone or incremental. Default is auto.
• recoveryProgress: Integer value to indicate the recovery process verbosity level.
• cloneDonor: host:port of an existing member of the PRIMARY cluster to clone from. IPv6 addresses are not supported for this option.
• manualStartOnBoot: boolean (default false). If false, Group Replication in cluster instances will automatically start and rejoin when MySQL starts, otherwise it must be started manually.
• memberSslMode: SSL mode for communication channels opened by Group Replication from one server to another.
• certSubject: instance's certificate subject to use when 'memberAuthType' contains "CERT_SUBJECT" or "CERT_SUBJECT_PASSWORD".
• ipAllowlist: The list of hosts allowed to connect to the instance for group replication. Only valid if communicationStack=XCOM.
• localAddress: string value with the Group Replication local address to be used instead of the automatically generated one.
• exitStateAction: string value indicating the group replication exit state action.
• memberWeight: integer value with a percentage weight for automatic primary election on failover.
• consistency: string value indicating the consistency guarantees that the cluster provides.
• expelTimeout: integer value to define the time period in seconds that cluster members should wait for a non-responding member before evicting it from the cluster.
• autoRejoinTries: integer value to define the number of times an instance will attempt to rejoin the cluster after being expelled.
• timeout: maximum number of seconds to wait for the instance to sync up with the PRIMARY Cluster. Default is 0 and it means no timeout.
• replicationAllowedHost: string value to use as the host name part of internal replication accounts (i.e. 'mysql_innodb_cluster_###'@'hostname'). Default is %. It must be possible for any member of the Cluster to connect to any other member using accounts with this hostname value.
• communicationStack: The Group Replication communication stack to be used in the Cluster: XCom (legacy) or MySQL.
• transactionSizeLimit: integer value to configure the maximum transaction size in bytes which the Cluster accepts
• paxosSingleLeader: boolean value used to enable/disable the Group Communication engine to operate with a single consensus leader.
• clusterSetReplicationConnectRetry: integer that specifies the interval in seconds between the reconnection attempts that the replica makes after the connection to the source times out.
• clusterSetReplicationRetryCount: integer that sets the maximum number of reconnection attempts that the replica makes after the connection to the source times out.
• clusterSetReplicationHeartbeatPeriod: decimal that controls the heartbeat interval, which stops the connection timeout occurring in the absence of data if the connection is still good.
• clusterSetReplicationCompressionAlgorithms: string that specifies the permitted compression algorithms for connections to the replication source.
• clusterSetReplicationZstdCompressionLevel: integer that specifies the compression level to use for connections to the replication source server that use the zstd compression algorithm.
• clusterSetReplicationBind: string that determines which of the replica's network interfaces is chosen for connecting to the source.
• clusterSetReplicationNetworkNamespace: string that specifies the network namespace to use for TCP/IP connections to the replication source server or, if the MySQL communication stack is in use, for Group Replication’s group communication connections.

The recoveryMethod option supports the following values:

• incremental: waits until the new instance has applied missing transactions from the PRIMARY
• clone: uses MySQL clone to provision the instance, which completely replaces the state of the target instance with a full snapshot of another ClusterSet member.
• auto: compares the transaction set of the instance with that of the PRIMARY to determine if incremental recovery is safe to be automatically chosen as the most appropriate recovery method. A prompt will be shown if not possible to safely determine a safe way forward. If interaction is disabled, the operation will be canceled instead.

If recoveryMethod is not specified 'auto' will be used by default.

The recoveryProgress option supports the following values:

• 0: do not show any progress information.
• 1: show detailed static progress information.
• 2: show detailed dynamic progress information using progress bars.

By default, if the standard output on which the Shell is running refers to a terminal, the recoveryProgress option has the value of 2. Otherwise, it has the value of 1.

The cloneDonor option is used to override the automatic selection of a donor to be used when clone is selected as the recovery method. By default, a SECONDARY member will be chosen as donor. If no SECONDARY members are available the PRIMARY will be selected. The option accepts values in the format: 'host:port'. IPv6 addresses are not supported.

The memberSslMode option controls whether TLS is to be used for connections opened by Group Replication from one server to another (both recovery and group communication, in either communication stack). It also controls what kind of verification the client end of connections perform on the SSL certificate presented by the server end.

The memberSslMode option supports the following values:

• REQUIRED: if used, SSL (encryption) will be enabled for the instances to communicate with other members of the cluster
• VERIFY_CA: Like REQUIRED, but additionally verify the peer server TLS certificate against the configured Certificate Authority (CA) certificates.
• VERIFY_IDENTITY: Like VERIFY_CA, but additionally verify that the peer server certificate matches the host to which the connection is attempted.
• DISABLED: if used, SSL (encryption) will be disabled
• AUTO: if used, SSL (encryption) will be enabled if supported by the instance, otherwise disabled

If memberSslMode is not specified AUTO will be used by default.

The ipAllowlist format is a comma separated list of IP addresses or subnet CIDR notation, for example: 192.168.1.0/24,10.0.0.1. By default the value is set to AUTOMATIC, allowing addresses from the instance private network to be automatically set for the allowlist.

This option is only used and allowed when communicationStack is set to XCOM.

The groupName and localAddress are advanced options and their usage is discouraged since incorrect values can lead to Group Replication errors.

The value for groupName is used to set the Group Replication system variable 'group_replication_group_name'.

The value for localAddress is used to set the Group Replication system variable 'group_replication_local_address'. The localAddress option accepts values in the format: 'host:port' or 'host:' or ':port'. If the specified value does not include a colon (:) and it is numeric, then it is assumed to be the port, otherwise it is considered to be the host. When the host is not specified, the default value is the value of the system variable 'report_host' if defined (i.e., not 'NULL'), otherwise it is the hostname value. When the port is not specified, the default value is the port of the target instance if the communication stack in use by the Cluster is 'MYSQL', otherwise, port * 10 + 1 when the communication stack is 'XCOM'. In case the automatically determined default port value is invalid (> 65535) then an error is thrown.

The exitStateAction option supports the following values:

• ABORT_SERVER: if used, the instance shuts itself down if it leaves the cluster unintentionally or exhausts its auto-rejoin attempts.
• READ_ONLY: if used, the instance switches itself to super-read-only mode if it leaves the cluster unintentionally or exhausts its auto-rejoin attempts.
• OFFLINE_MODE: if used, the instance switches itself to offline mode if it leaves the cluster unintentionally or exhausts its auto-rejoin attempts. Requires MySQL 8.0.18 or newer.

If exitStateAction is not specified, it defaults to OFFLINE_MODE for server versions 8.4.0 or newer, and READ_ONLY otherwise.

The consistency option supports the following values:

• BEFORE_ON_PRIMARY_FAILOVER: if used, new queries (read or write) to the new primary will be put on hold until after the backlog from the old primary is applied.
• EVENTUAL: if used, read queries to the new primary are allowed even if the backlog isn't applied.

If consistency is not specified, it defaults to BEFORE_ON_PRIMARY_FAILOVER for server versions 8.4.0 or newer, and EVENTUAL otherwise.

The value for exitStateAction is used to configure how Group Replication behaves when a server instance leaves the group unintentionally (for example after encountering an applier error) or exhausts its auto-rejoin attempts. When set to ABORT_SERVER, the instance shuts itself down. When set to READ_ONLY the server switches itself to super-read-only mode. When set to OFFLINE_MODE it switches itself to offline mode. In this mode, connected client users are disconnected on their next request and connections are no longer accepted, with the exception of client users that have the CONNECTION_ADMIN or SUPER privilege. The exitStateAction option accepts case-insensitive string values, being the accepted values: OFFLINE_MODE (or 2), ABORT_SERVER (or 1) and READ_ONLY (or 0).

The default value is OFFLINE_MODE for server versions 8.4.0 or newer, and READ_ONLY otherwise.

The value for memberWeight is used to set the Group Replication system variable 'group_replication_member_weight'. The memberWeight option accepts integer values. Group Replication limits the value range from 0 to 100, automatically adjusting it if a lower/bigger value is provided.

Group Replication uses a default value of 50 if no value is provided.

The value for consistency is used to set the Group Replication system variable 'group_replication_consistency' and configure the transaction consistency guarantee which a cluster provides.

When set to BEFORE_ON_PRIMARY_FAILOVER, whenever a primary failover happens in single-primary mode (default), new queries (read or write) to the newly elected primary that is applying backlog from the old primary, will be hold before execution until the backlog is applied. Special care is needed if LOCK / UNLOCK queries are used in a secondary, because the UNLOCK statement can be held. This means that, if the secondary is promoted, and transactions from the primary are being applied that target locked tables, they won't be applied and an explicit UNLOCK will also hold because the secondary needs to finish applying the transactions from the previous primary. See https://dev.mysql.com/doc/refman/en/group-replication-system-variables.html#sysvar_group_replication_consistency for more details.

When set to EVENTUAL, read queries to the new primary are allowed even if the backlog isn't applied but writes will fail (if the backlog isn't applied) due to super-read-only mode being enabled. The client may return old values.

When set to BEFORE, each transaction (RW or RO) waits until all preceding transactions are complete before starting its execution. This ensures that each transaction is executed on the most up-to-date snapshot of the data, regardless of which member it is executed on. The latency of the transaction is affected but the overhead of synchronization on RW transactions is reduced since synchronization is used only on RO transactions.

When set to AFTER, each RW transaction waits until its changes have been applied on all of the other members. This ensures that once this transaction completes, all following transactions read a database state that includes its changes, regardless of which member they are executed on. This mode shall only be used on a group that is used for predominantly RO operations to ensure that subsequent reads fetch the latest data which includes the latest writes. The overhead of synchronization on every RO transaction is reduced since synchronization is used only on RW transactions.

When set to BEFORE_AND_AFTER, each RW transaction waits for all preceding transactions to complete before being applied and until its changes have been applied on other members. A RO transaction waits for all preceding transactions to complete before execution takes place. This ensures the guarantees given by BEFORE and by AFTER. The overhead of synchronization is higher.

The consistency option accepts case-insensitive string values, being the accepted values: EVENTUAL (or 0), BEFORE_ON_PRIMARY_FAILOVER (or 1), BEFORE (or 2), AFTER (or 3), and BEFORE_AND_AFTER (or 4).

It defaults to BEFORE_ON_PRIMARY_FAILOVER for server versions 8.4.0 or newer, and EVENTUAL otherwise.

The value for expelTimeout is used to set the Group Replication system variable 'group_replication_member_expel_timeout' and configure how long Group Replication will wait before expelling from the group any members suspected of having failed. On slow networks, or when there are expected machine slowdowns, increase the value of this option. The expelTimeout option accepts positive integer values and, since 8.0.21, defaults to 5 seconds.

The value for autoRejoinTries is used to set the Group Replication system variable 'group_replication_autorejoin_tries' and configure how many times an instance will try to rejoin a Group Replication group after being expelled. In scenarios where network glitches happen but recover quickly, setting this option prevents users from having to manually add the expelled node back to the group. The autoRejoinTries option accepts positive integer values and, since 8.0.21, defaults to 3.

The value for communicationStack is used to choose which Group Replication communication stack must be used in the Cluster. It's used to set the value of the Group Replication system variable 'group_replication_communication_stack'.

When set to legacy 'XCom', all internal GCS network traffic (PAXOS and communication infrastructure) flows through a separate network address: the localAddress.

When set to 'MySQL', such traffic re-uses the existing MySQL Server facilities to establish connections among Cluster members. It allows a simpler and safer setup as it obsoletes the usage of IP allowlists (ipAllowlist), removes the explicit need to have a separate network address (localAddress), and introduces user-based authentication.

The default value for Clusters running 8.0.27+ is 'MySQL'.

The value for transactionSizeLimit is used to set the Group Replication system variable 'group_replication_transaction_size_limit' and configures the maximum transaction size in bytes which the Cluster accepts. Transactions larger than this size are rolled back by the receiving member and are not broadcast to the Cluster.

The transactionSizeLimit option accepts positive integer values and, if set to zero, there is no limit to the size of transactions the Cluster accepts

All members added or rejoined to the Cluster will use the same value.

The value for paxosSingleLeader is used to enable or disable the Group Communication engine to operate with a single consensus leader when the Cluster is in single-primary more. When enabled, the Cluster uses a single leader to drive consensus which improves performance and resilience in single-primary mode, particularly when some of the Cluster's members are unreachable.

The option is available on MySQL 8.0.31 or newer and the default value is 'OFF'.

remove_cluster()

None remove_cluster	(	str	clusterName,
		dict	options
	)

Removes a Replica cluster from a ClusterSet.

Parameters

clusterName	The name identifier of the Replica cluster to be removed.
options	optional Dictionary with additional parameters described below.

Returns

Nothing.

Removes a MySQL InnoDB Replica Cluster from the target ClusterSet.

The Cluster is removed from the ClusterSet and implicitly dissolved, i.e. each member of it becomes a standalone instance.

For the Cluster to be successfully removed from the ClusterSet the PRIMARY Cluster must be available and the ClusterSet replication channel healthy. If those conditions aren't met the Cluster can still be forcefully removed using the 'force' option, however, its Metadata won't be updated compromising the effortless usage of its members to create new Clusters and/or add to existing Clusters. To re-use those instances, the Metadata schema must be dropped using dba.drop_metadata_schema(), or the Cluster rebooted from complete outage using dba.reboot_cluster_from_complete_outage().

Options

The options dictionary can contain the following values:

• force: boolean, indicating if the cluster must be removed (even if only from metadata) in case the PRIMARY cannot be reached, or the ClusterSet replication channel cannot be found or is stopped. By default, set to false.
• dissolve: whether to dissolve the cluster after removing it from the ClusterSet. Set to false if you intend to use it as a standalone cluster. Default is true.
• timeout: maximum number of seconds to wait for the instance to sync up with the PRIMARY Cluster. Default is 0 and it means no timeout.
• dryRun: boolean if true, all validations and steps for removing a the Cluster from the ClusterSet are executed, but no changes are actually made. An exception will be thrown when finished.

NOTE: if dissolve is set to false it will not be possible to add the removed cluster back to the ClusterSet, because transactions that are not in the ClusterSet will be executed there.

rejoin_cluster()

None rejoin_cluster	(	str	clusterName,
		dict	options
	)

Rejoin an invalidated Cluster back to the ClusterSet and update replication.

Parameters

clusterName	Name of the Cluster to be rejoined.
options	optional Dictionary with additional parameters described below.

Returns

Nothing

Rejoins a Cluster that was invalidated as part of a failover or switchover, if possible. This can also be used to update replication channel in REPLICA Clusters, if it does not have the expected state, source and settings.

The PRIMARY Cluster of the ClusterSet must be reachable and available during the operation.

Pre-Requisites

The following pre-requisites are expected for Clusters rejoined to a ClusterSet. They will be automatically checked by rejoinCluster(), which will stop if any issues are found.

• The target Cluster must belong to the ClusterSet metadata and be reachable.
• The target Cluster must not be an active member of the ClusterSet.
• The target Cluster must not be holding any Metadata or InnoDB transaction lock.
• The target Cluster's transaction set must not contain transactions that don't exist in the PRIMARY Cluster.
• The target Cluster's transaction set must not be missing transactions that have been purged from the PRIMARY Cluster.
• The target Cluster's executed transaction set (GTID_EXECUTED) must not be empty.

Options

The following options may be given:

• dryRun: if true, will perform checks and log operations that would be performed, but will not execute them. The operations that would be performed can be viewed by enabling verbose output in the shell.

set_primary_cluster()

None set_primary_cluster	(	str	clusterName,
		dict	options
	)

Performs a safe switchover of the PRIMARY Cluster of the ClusterSet.

Parameters

clusterName	Name of the REPLICA cluster to be promoted.
options	optional Dictionary with additional parameters described below.

Returns

Nothing

This command will perform a safe switchover of the PRIMARY Cluster of a ClusterSet. The current PRIMARY will be demoted to a REPLICA Cluster, while the promoted Cluster will be made the PRIMARY Cluster. All other REPLICA Clusters will be updated to replicate from the new PRIMARY.

During the switchover, the promoted Cluster will be synchronized with the old PRIMARY, ensuring that all transactions present in the PRIMARY are applied before the topology change is committed. The current PRIMARY instance is also locked with 'FLUSH TABLES WITH READ LOCK' in order to prevent changes during the switch. If either of these operations take too long or fails, the switch will be aborted.

For a switchover to be possible, all instances of the target Cluster must be reachable from the shell and have consistent transaction sets with the current PRIMARY Cluster. If the PRIMARY Cluster is not available and cannot be restored, a failover must be performed instead, using ClusterSet.force_primary_cluster().

The switchover will be canceled if there are REPLICA Clusters that are unreachable or unavailable. To continue, they must either be restored or invalidated by including their name in the 'invalidateReplicaClusters' option. Invalidated REPLICA Clusters must be either removed from the Cluster or restored and rejoined, using remove_cluster() or rejoin_cluster().

Additionally, if any available REPLICA Cluster has members that are not ONLINE and/or reachable, these members will not be in a properly configured state even after being restored and rejoined. To ensure failover works correctly, rejoin_cluster() must be called on the Cluster once these members are rejoined.

Options

The following options may be given:

• dryRun: if true, will perform checks and log operations that would be performed, but will not execute them. The operations that would be performed can be viewed by enabling verbose output in the shell.
• timeout: integer value to set the maximum number of seconds to wait for the synchronization of the Cluster and also for the instance being promoted to catch up with the current PRIMARY (in the case of the latter, the default value is retrieved from the 'dba.gtidWaitTimeout' shell option).
• invalidateReplicaClusters: list of names of REPLICA Clusters that are unreachable or unavailable that are to be invalidated during the switchover.

force_primary_cluster()

None force_primary_cluster	(	str	clusterName,
		dict	options
	)

Performs a failover of the PRIMARY Cluster of the ClusterSet.

Parameters

clusterName	Name of the REPLICA cluster to be promoted.
options	optional Dictionary with additional parameters described below.

Returns

Nothing

This command will perform a failover of the PRIMARY Cluster of a ClusterSet. The target cluster is promoted to the new PRIMARY Cluster while the previous PRIMARY Cluster is invalidated. The previous PRIMARY Cluster is presumed unavailable by the Shell, but if that is not the case, it is recommended that instances of that Cluster are taken down to avoid or minimize inconsistencies.

The failover will be canceled if there are REPLICA Clusters that are unreachable or unavailable. To continue, they must either be restored or invalidated by including their name in the 'invalidateReplicaClusters' option.

Additionally, if any available REPLICA Cluster has members that are not ONLINE and/or reachable, these members will not be in a properly configured state even after being restored and rejoined. To ensure failover works correctly, rejoin_cluster() must be called on the Cluster once these members are rejoined.

Note that because a failover may result in loss of transactions, it is always preferrable that the PRIMARY Cluster is restored.

Aftermath of a Failover

If a failover is the only viable option to recover from an outage, the following must be considered:

• The topology of the ClusterSet, including a record of "who is the primary", is stored in the ClusterSet itself. In a failover, the metadata is updated to reflect the new topology and the invalidation of the old primary. However, if the invalidated primary is still ONLINE somewhere, the copy of the metadata held there will will remain outdated and inconsistent with the actual topology. MySQL Router instances that can connect to the new PRIMARY Cluster will be able to tell which topology is the correct one, but those instances that can only connect to the invalid Cluster will behave as if nothing changed. If applications can still update the database through such Router instances, there will be a "Split-Brain" and the database will become inconsistent. To avoid such scenario, fence the old primary from all traffic using Cluster.fence_all_traffic(), or from write traffic only using Cluster.fence_writes().

• An invalidated PRIMARY Cluster that is later restored can only be rejoined if its GTID set has not diverged relative to the rest of the ClusterSet.

• A diverged invalidated Cluster can only be removed from the ClusterSet. Recovery and reconciliation of transactions that only exist in that Cluster can only be done manually.

• Because regular Asynchronous Replication is used between PRIMARY and REPLICA Clusters, any transactions at the PRIMARY that were not yet replicated at the time of the failover will be lost. Even if the original PRIMARY Cluster is restored at some point, these transactions would have to be recovered and reconciled manually.

Thus, the recommended course of action in event of an outage is to always restore the PRIMARY Cluster if at all possible, even if a failover may be faster and easier in the short term.

Options

The following options may be given:

• dryRun: if true, will perform checks and log operations that would be performed, but will not execute them. The operations that would be performed can be viewed by enabling verbose output in the shell.
• invalidateReplicaClusters: list of names of REPLICA Clusters that are unreachable or unavailable that are to be invalidated during the failover.
• timeout: integer value with the maximum number of seconds to wait for pending transactions to be applied in each instance of the cluster (default value is retrieved from the 'dba.gtidWaitTimeout' shell option).

status()

str status

(

dict

options

)

Describe the status of the ClusterSet.

Parameters

options

optional Dictionary with additional parameters described below.

Returns

A JSON object describing the status of the ClusterSet and its members.

This function describes the status of the ClusterSet including its members (Clusters).

The function will gather state information from each member of the ClusterSet and the replication channel of it to produce a status report of the ClusterSet as a whole.

Options

The following options may be given to control the amount of information gathered and returned.

• extended: verbosity level of the command output. Default is 0.

Option 'extended' may have the following values:

• 0: regular level of details. Only basic information about the status of the ClusterSet and Cluster members.
• 1: includes basic information about the status of each cluster, information about each cluster member role and state as reported by Group Replication, and information about the ClusterSet Replication channel.
• 2: includes the list of the fenced system variables, applier worker threads, member ID, etc. The information about the ClusterSet Replication channel is extended to include information about the applier queue size, applier queue GTID set, coordinator state, etc.
• 3: includes important replication related configuration settings, such as replication delay, heartbeat delay, retry count and connection retry for the ClusterSet replication channel.

describe()

shcore::Value describe

(

void

)

Describe the structure of the ClusterSet.

Returns

A JSON object describing the structure of the ClusterSet.

This function describes the status of the ClusterSet including its members (Clusters).

This function describes the structure of the ClusterSet including all its information and Clusters belonging to it.

The returned JSON object contains the following attributes:

• domainName: The ClusterSet domain name
• primaryCluster: The current primary Cluster of the ClusterSet
• clusters: the list of members of the ClusterSet

The clusters JSON object contains the following attributes:

• clusterRole: The role of the Cluster
• a list of dictionaries describing each instance belonging to the Cluster.

Each instance dictionary contains the following attributes:

• address: the instance address in the form of host:port
• label: the instance name identifier

dissolve()

None dissolve

(

dict

options

)

Dissolves the ClusterSet.

Parameters

options

Dictionary with options for the operation.

Returns

Nothing

This function dissolves the ClusterSet by removing all Clusters that belong to it, implicitly dissolving each one.

It keeps all the user's data intact.

Options

The options dictionary may contain the following attributes:

• force: set to true to confirm that the dissolve operation must be executed, even if some members of the ClusterSet cannot be reached or the timeout was reached when waiting for members to catch up with replication changes. By default, set to false.
• timeout: maximum number of seconds to wait for pending transactions to be applied in each reachable instance of the ClusterSet (default value is retrieved from the 'dba.gtidWaitTimeout' shell option).
• dryRun: if true, all validations and steps for dissolving the ClusterSet are executed, but no changes are actually made.

The force option (set to true) must only be used to dissolve a ClusterSet with Clusters that are permanently unavailable (no longer reachable), or if any instance of any Cluster is also permanently unavailable.

set_routing_option()

None set_routing_option	(	str	router,
		str	option,
		str	value
	)

Changes the value of either a global Routing option or of a single Router instance.

Parameters

router	optional identifier of the target router instance (e.g. 192.168.45.70::system).
option	The Router option to be changed.
value	The value that the option shall get (or null to unset).

Returns

Nothing.

The accepted options are:

• target_cluster: Target Cluster for Router routing operations. Default value is 'primary'.
• invalidated_cluster_policy: Routing policy to be taken when the target cluster is detected as being invalidated. Default value is 'drop_all'.
• stats_updates_frequency: Number of seconds between updates that the Router is to make to its statistics in the InnoDB Cluster metadata.
• use_replica_primary_as_rw: Enable/Disable the RW Port in Replica Clusters. Disabled by default.
• tags: Associates an arbitrary JSON object with custom key/value pairs with the ClusterSet metadata.
• read_only_targets: Routing policy to define Router's usage of Read Replicas. Default is 'append'.

The target_cluster option supports the following values:

• primary: Follow the Primary Cluster whenever it changes in runtime ( default).
• <clusterName>: Use the Cluster named <clusterName> as target.

The invalidated_cluster_policy option supports the following values:

• accept_ro: all the RW connections are be dropped and no new RW connections are be accepted. RO connections keep being accepted and handled.
• drop_all: all connections to the target Cluster are closed and no new connections will be accepted (default).

The stats_updates_frequency option accepts positive integers and sets the frequency of updates of Router stats (timestamp, version, etc.), in seconds, in the Metadata. If set to 0 (default), no periodic updates are done. Router will round up the value to be a multiple of Router's TTL, i.e.:

• If lower than TTL its gets rounded up to TTL, e.g. TTL=30, and stats_updates_frequency=1, effective frequency is 30 seconds.

• If not a multiple of TTL it will be rounded up and adjusted according to the TTL, e.g. TTL=5, stats_updates_frequency=11, effective frequency is 15 seconds; TTL=5, stats_updates_frequency=13, effective frequency is 15 seconds.

If the value is null, the option value is cleared and the default value (0) takes effect.

The use_replica_primary_as_rw option accepts a boolean value to configure whether the Router should enable or disable the RW Port for the target Cluster.

When enabled, forces the RW port of Routers targeting a specific Cluster (target_cluster != 'primary') to always route to the PRIMARY of that Cluster, even when it is in a REPLICA cluster and thus, read-only. By default, the option is false and Router blocks connections to the RW port in this scenario.

The read_only_targets option supports the following values:

• all: All Read Replicas of the target Cluster should be used along the other SECONDARY Cluster members for R/O traffic.
• read_replicas: Only Read Replicas of the target Cluster should be used for R/O traffic.
• secondaries: Only Secondary members of the target Cluster should be used for R/O traffic (default).

setup_admin_account()

None setup_admin_account	(	str	user,
		dict	options
	)

Create or upgrade an InnoDB ClusterSet admin account.

Parameters

user	Name of the InnoDB ClusterSet administrator account.
options	Dictionary with options for the operation.

Returns

Nothing.

This function creates/upgrades a MySQL user account with the necessary privileges to administer an InnoDB ClusterSet.

This function also allows a user to upgrade an existing admin account with the necessary privileges before a dba.upgrade_metadata() call.

The mandatory argument user is the name of the MySQL account we want to create or upgrade to be used as Administrator account. The accepted format is username[@host] where the host part is optional and if not provided defaults to ''.

The options dictionary may contain the following attributes:

• password: The password for the InnoDB ClusterSet administrator account.
• passwordExpiration: Password expiration setting for the account. May be set to the number of days for expiration, 'NEVER' to disable expiration and 'DEFAULT' to use the system default.
• requireCertIssuer: Optional SSL certificate issuer for the account.
• requireCertSubject: Optional SSL certificate subject for the account.
• dryRun: boolean value used to enable a dry run of the account setup process. Default value is False.
• update: boolean value that must be enabled to allow updating the privileges and/or password of existing accounts. Default value is False.

If the user account does not exist, either the password, requireCertIssuer or requireCertSubject are mandatory.

If the user account exists, the update option must be enabled.

If dryRun is used, the function will display information about the permissions to be granted to `user` account without actually creating and/or performing any changes to it.

To change authentication options for an existing account, set `update` to `true`. It is possible to change password without affecting certificate options or vice-versa but certificate options can only be changed together.

setup_router_account()

None setup_router_account	(	str	user,
		dict	options
	)

Create or upgrade a MySQL account to use with MySQL Router.

Parameters

user	Name of the account to create/upgrade for MySQL Router.
options	Dictionary with options for the operation.

Returns

Nothing.

This function creates/upgrades a MySQL user account with the necessary privileges to be used by MySQL Router.

This function also allows a user to upgrade existing MySQL router accounts with the necessary privileges after a dba.upgrade_metadata() call.

The mandatory argument user is the name of the MySQL account we want to create or upgrade to be used by MySQL Router. The accepted format is username[@host] where the host part is optional and if not provided defaults to ''.

The options dictionary may contain the following attributes:

• password: The password for the MySQL Router account.
• passwordExpiration: Password expiration setting for the account. May be set to the number of days for expiration, 'NEVER' to disable expiration and 'DEFAULT' to use the system default.
• requireCertIssuer: Optional SSL certificate issuer for the account.
• requireCertSubject: Optional SSL certificate subject for the account.
• dryRun: boolean value used to enable a dry run of the account setup process. Default value is False.
• update: boolean value that must be enabled to allow updating the privileges and/or password of existing accounts. Default value is False.

If the user account does not exist, either the password, requireCertIssuer or requireCertSubject are mandatory.

If the user account exists, the update option must be enabled.

If dryRun is used, the function will display information about the permissions to be granted to `user` account without actually creating and/or performing any changes to it.

To change authentication options for an existing account, set `update` to `true`. It is possible to change password without affecting certificate options or vice-versa but certificate options can only be changed together.

routing_options()

dict routing_options

(

str

router

)

Lists the ClusterSet Routers configuration options.

Parameters

router

Optional identifier of the router instance to query for the options.

Returns

A JSON object describing the configuration options of all router instances of the ClusterSet and its global options or just the given Router.

Attention

This function is deprecated and will be removed in a future release of MySQL Shell. Use ClusterSet.routerOptions() instead.

This function lists the Router configuration options of all Routers of the ClusterSet or the target Router.

list_routers()

dict list_routers

(

str

router

)

Lists the Router instances of the ClusterSet, or a single Router instance.

Parameters

router

optional identifier of the target router instance (e.g. 192.168.45.70::system)

Returns

A JSON object listing the Router instances registered in the ClusterSet.

This function lists and provides information about all Router instances registered on the Clusters members of the ClusterSet.

For each router, the following information is provided, when available:

• hostname: Hostname.
• lastCheckIn: Timestamp of the last statistics update (check-in).
• roPort: Read-only port (Classic protocol).
• roXPort: Read-only port (X protocol).
• rwPort: Read-write port (Classic protocol).
• rwSplitPort: Read-write split port (Classic protocol).
• rwXPort: Read-write port (X protocol).
• targetCluster: Target Cluster for Router routing operations.
• version: Version.

set_option()

None set_option	(	str	option,
		str	value
	)

Changes the value of an option for the whole ClusterSet.

Parameters

option	The option to be changed.
value	The value that the option shall get.

Returns

Nothing.

This function changes an option for the ClusterSet.

The accepted options are:

• replicationAllowedHost string value to use as the host name part of internal replication accounts. Existing accounts will be re-created with the new value.

options()

shcore::Value options

(

)

Lists the ClusterSet configuration options.

Returns

A JSON object describing the configuration options of the ClusterSet.

This function lists the configuration options for the ClusterSet.

execute()

dict execute	(	str	cmd,
		object	instances,
		dict	options
	)

Executes a SQL statement at selected instances of the ClusterSet.

Parameters

cmd	The SQL statement to execute.
instances	The instances where cmd should be executed.
options	Dictionary with options for the operation.

Returns

A JSON object with a list of results / information regarding the executing of the SQL statement on each of the target instances.

This function allows a single MySQL SQL statement to be executed on multiple instances of the ClusterSet.

The 'instances' parameter can be either a string (keyword) or a list of instance addresses where cmd should be executed. If a string, the allowed keywords are:

• "all" / "a": all reachable instances.
• "primary" / "p": the primary instance of the primary cluster.
• "secondaries" / "s": the secondary instances on all clusters.
• "read-replicas" / "rr": the read-replicas instances on all clusters.

The options dictionary may contain the following attributes:

• exclude: similar to the instances parameter, it can be either a string (keyword) or a list of instance addresses to exclude from the instances specified in instances. It accepts the same keywords, except "all".
• timeout: integer value with the maximum number of seconds to wait for cmd to execute in each target instance. Default value is 0 meaning it doesn't timeout.
• dryRun: boolean if true, all validations and steps for executing cmd are performed, but no cmd is actually executed on any instance.

To calculate the final list of instances where cmd should be executed, the function starts by parsing the instances parameter and then subtract from that list the ones specified in the exclude option. For example, if instances is "all" and exclude is "secondaries", then all primaries (on the primary and replica clusters) and all read-replicas are targeted.