Managing replica sets | Tarantool
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Справочники Tooling tt CLI utility Commands Managing replica sets

Managing replica sets

$ tt replicaset COMMAND {APPLICATION[:APP_INSTANCE] | URI} [OPTIONS ...]
# or
$ tt rs COMMAND {APPLICATION[:APP_INSTANCE] | URI} [OPTIONS ...]

tt replicaset (or tt rs) manages a Tarantool replica set.

COMMAND is one of the following:

status

$ tt replicaset status {APPLICATION[:APP_INSTANCE] | URI} [OPTIONS ...]
# or
$ tt rs status  {APPLICATION[:APP_INSTANCE] | URI} [OPTIONS ...]

tt replicaset status (tt rs status) shows the current status of a replica set.

Displaying status of all replica sets

To view the status of all replica sets of an application in the current tt environment, run tt replicaset status with the application name:

$ tt replicaset status myapp

Displaying status of a single replica set

To view the status of a single replica set of an application, run tt replicaset status with a name or a URI of an instance from this replica set:

$ tt replicaset status myapp:storage-001-a

For a replica outside the current tt environment, specify its URI and access credentials:

$ tt replicaset status 192.168.10.10:3301 -u myuser -p p4$$w0rD

Learn about other ways to provide user credentials in Authentication.

promote

$ tt replicaset promote {APPLICATION:APP_INSTANCE | URI} [OPTIONS ...]
# or
$ tt rs promote {APPLICATION:APP_INSTANCE | URI} [OPTIONS ...]

tt replicaset promote (tt rs promote) promotes the specified instance, making it a leader of its replica set. This command works on Tarantool clusters with a local YAML configuration and Cartridge clusters.

Примечание

To promote an instance in a Tarantool cluster with a centralized configuration, use tt cluster replicaset promote.

Promoting in clusters with local YAML configurations

tt replicaset promote works on Tarantool clusters with local YAML configurations with failover modes off, manual, and election.

In failover modes off or manual, this command updates the cluster configuration file according to the specified arguments and reloads it:

  • off failover mode: the command sets database.mode to rw on the specified instance.

    Важно

    If failover is off, the command doesn’t consider the modes of other replica set members, so there can be any number of read-write instances in one replica set.

  • manual failover mode: the command updates the leader option of the replica set configuration. Other instances of this replica set become read-only.

Example:

$ tt replicaset promote my-app:storage-001-a

If some members of the affected replica set are running outside the current tt environment, tt replicaset promote can’t ensure the configuration reload on them and reports an error. You can skip this check by adding the -f/--force option:

$ tt replicaset promote my-app:storage-001-a --force

In the election failover mode, tt replicaset promote initiates the new leader election by calling box.ctl.promote() on the specified instance. The --timeout option can be used to specify the election completion timeout:

$ tt replicaset promote my-app:storage-001-a --timeout=10

Promoting in Cartridge clusters

Важно

The Tarantool Cartridge framework is deprecated and is not compatible with Tarantool 3.0 and later. This command is added for backward compatibility with earlier versions.

tt replicaset promote promotes instances in Cartridge clusters as follows:

  • disabled or eventual failover mode: the command changes the instance failover priority.

    Важно

    In these cases, consistency is not guaranteed and replication conflicts may occur.

  • eventual or raft failover mode: the command calls cartridge.failover_promote() and waits until the instance transitions to the read-write mode. If the -f/--force option is specified, the force_inconsistency option of cartridge.failover_promote is set to true.

$ tt replicaset promote my-cartridge-app:storage-001-a --force

Learn more about Cartridge failover modes.

demote

$ tt replicaset demote APPLICATION:APP_INSTANCE [OPTIONS ...]
# or
$ tt rs demote APPLICATION:APP_INSTANCE [OPTIONS ...]

tt replicaset demote (tt rs demote) demotes an instance in a Tarantool cluster with a local YAML configuration.

Примечание

To demote an instance in a Tarantool cluster with a centralized configuration, use tt cluster replicaset demote.

Demoting in clusters with local YAML configurations

tt replicaset demote can demote instances in Tarantool clusters with local YAML configurations with failover modes off and election.

Примечание

In clusters with manual failover mode, you can demote a read-write instance by promoting a read-only instance from the same replica set with tt replicaset promote.

In the off failover mode, tt replicaset demote sets the instance’s database.mode to ro and reloads the configuration.

Важно

If failover is off, the command doesn’t consider the modes of other replica set members, so there can be any number of read-write instances in one replica set.

If some members of the affected replica set are running outside the current tt environment, tt replicaset demote can’t ensure the configuration reload on them and reports an error. You can skip this check by adding the -f/--force option:

$ tt replicaset demote my-app:storage-001-a --force

In the election failover mode, tt replicaset demote initiates a leader election in the replica set. The specified instance’s replication.election_mode is changed to voter for this election, which guarantees that another instance is elected as a new replica set leader.

The --timeout option can be used to specify the election completion timeout:

$ tt replicaset demote my-app:storage-001-a --timeout=10

Selecting the application orchestrator manually

You can specify the orchestrator to use for the application when calling tt replicaset commands. The following options are available:

  • --config for applications that use YAML cluster configuration (Tarantool 3.x or later).
  • --cartridge for Cartridge applications (Tarantool 2.x).
  • --custom for any other orchestrators used on Tarantool 2.x clusters.
$ tt replicaset status myapp --config
$ tt replicaset promote my-cartridge-app:storage-001-a --cartridge

If an actual orchestrator that the application uses does not match the specified option, an error is raised.

Authentication

Use one of the following ways to pass the credentials of a Tarantool user when connecting to the instance by its URI:

  • The -u (--username) and -p (--password) options:

    $ tt replicaset status 192.168.10.10:3301 -u myuser -p p4$$w0rD

  • The connection string:

    $ tt replicaset status myuser:p4$$w0rD@192.168.10.10:3301

  • Environment variables TT_CLI_USERNAME and TT_CLI_PASSWORD:

    $ export TT_CLI_USERNAME=myuser
$ export TT_CLI_PASSWORD=p4$$w0rD
$ tt replicaset status 192.168.10.10:3301

Options

--cartridge

Force the Cartridge orchestrator for Tarantool 2.x clusters.

--config

Force the YAML configuration orchestrator for Tarantool 3.0 or later clusters.

--custom

Force a custom orchestrator for Tarantool 2.x clusters.

-f, --force

Applicable to: promote, demote

Skip promotion or demotion if the specified instance is not running in the same environment.

-u USERNAME, --username USERNAME

A Tarantool user for connecting to the instance.

-p PASSWORD, --password PASSWORD

The user’s password.

--sslcertfile FILEPATH

The path to an SSL certificate file for encrypted connections.

--sslkeyfile FILEPATH

The path to a private SSL key file for encrypted connections.

--sslcafile FILEPATH

The path to a trusted certificate authorities (CA) file for encrypted connections.

--sslciphers STRING

The list of SSL cipher suites used for encrypted connections, separated by colons (:).

--timeout

Applicable to: promote, demote

The timeout for completing the promotion or demotion, in seconds. Default: 3.

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