Step 7: Start and Configure MariaDB MaxScale

Overview

This page details step 7 of the 9-step procedure "Deploy ColumnStore Shared Local Storage Topology".

This step starts and configures MariaDB MaxScale 6.2.

Interactive commands are detailed. Alternatively, the described operations can be performed using automation.

Replace the Default Configuration File

MariaDB MaxScale installations include a configuration file with some example objects. This configuration file should be replaced.

On the MaxScale node, replace the default /etc/maxscale.cnf with the following configuration:

[maxscale]
threads          = auto
admin_host       = 0.0.0.0
admin_secure_gui = false

For additional information, see "Global Parameters".

Restart MaxScale

On the MaxScale node, restart the MaxScale service to ensure that MaxScale picks up the new configuration:

$ sudo systemctl restart maxscale

Configure Server Objects

On the MaxScale node, use maxctrl create server to create a server object for each Enterprise ColumnStore node:

$ maxctrl create server mcs1 192.0.2.101
$ maxctrl create server mcs2 192.0.2.102
$ maxctrl create server mcs3 192.0.2.103

Configure MariaDB Monitor

MaxScale uses monitors to retrieve additional information from the servers. This information is used by other services in filtering and routing connections based on the current state of the node. For MariaDB Enterprise ColumnStore, use the MariaDB Monitor (mariadbmon).

On the MaxScale node, use maxctrl create monitor to create a MariaDB Monitor:

$ maxctrl create monitor columnstore_monitor mariadbmon \
      --monitor-user mxs --monitor-password 'maxscale_passwd' \
      replication_user=repl_user replication_password=repl_pass \
      --servers mcs1 mcs2 mcs3

In this example:

  • columnstore_monitor specifies an arbitrary name for the monitoring service.

  • mariadbmon indicates the monitor MaxScale uses to track changes in the node status.

  • --monitor-user specifies the user account MaxScale uses in connecting to the servers.

  • --monitor-password specifies the password for the user account on the servers.

  • replication_user=USER specifies the user account for the replication user.

  • replication_password=PASS specifies the password for the user account for the replication user.

  • --servers indicates the nodes MaxScale should monitor with this service.

Choose a MaxScale Router

Routers control how MaxScale balances the load between Enterprise ColumnStore nodes. Each router uses a different approach to routing queries. Consider the specific use case of your application and database load and select the router that best suits your needs.

Router

Configuration Procedure

Description

Read Connection (readconnroute)

Configure Read Connection Router

  • Connection-based load balancing

  • Routes connections to Enterprise ColumnStore nodes designated as replica servers for a read-only pool

  • Routes connections to an Enterprise ColumnStore node designated as the primary server for a read-write pool.

Read/Write Split (readwritesplit)

Configure Read/Write Split

  • Query-based load balancing

  • Routes write queries to an Enterprise ColumnStore node designated as the primary server

  • Routes read queries to Enterprise ColumnStore node designated as replica servers

  • Automatically reconnects after node failures

  • Automatically replays transactions after node failures

  • Optionally enforces causal reads

Configure Read Connection Router

Use MaxScale Read Connection Router (readconnroute) to route connections to replica servers for a read-only pool.

On the MaxScale node, use maxctrl create service to create a router:

$ maxctrl create service connection_router_service readconnroute \
      user=mxs password=mxs_passwd \
      router_options=slave \
      --servers mcs1 mcs2 mcs3

In this example:

  • connection_router_service is the arbitrary name of this routing service.

  • readconnroute is the specific router to use with this service, the Read Connection Router.

  • user indicates the user account MaxScale uses to connect to the servers.

  • password indicates the password for the user account.

  • slave is the router_options parameter, specified as a key=value pair. With this value, connections will only route to Enterprise ColumnStore nodes designated as replica servers.

  • --servers indicates the configured servers to which MaxScale should route queries.

Configure Listener for the Read Connection Router

These instructions reference TCP port 3308. You can use a different TCP port. The TCP port used must not be bound by any other listener.

On the MaxScale node, use the maxctrl create listener command to configure MaxScale to use a listener for the Read Connection Router (readconnroute):

$ maxctrl create listener connection_router_service connection_router_listener 3308 \
      --protocol=MariaDBClient

In this example:

  • connection_router_service is the name of the service that uses the Read Connection Router (readconnroute).

  • connection_router_listener is the name of the new listener.

  • 3308 is the TCP port.

  • MariaDBClient is the protocol, specified with the --protocol option.

  • Other Module Parameters supported by listeners in MaxScale 6.2 can also be specified.

Configure Read/Write Split Router for Queries

MaxScale Read/Write Split Router (readwritesplit) performs query-based load balancing. The router routes write queries to the primary and read queries to the replicas.

On the MaxScale node, use the maxctrl create service command to configure MaxScale to use the Read/Write Split Router (readwritesplit):

$ maxctrl create service query_router_service readwritesplit  \
      user=mxs \
      password=mxs_passwd \
      --servers mcs1 mcs2 mcs3

In this example:

  • query_router_service is the name of the new service that uses the Read/Write Split Router (readwritesplit).

  • readwritesplit is the name of the module that implements the Read/Write Split Router.

  • mxs is the database user account for MaxScale, specified as a key=value pair.

  • mxs_passwd is the password for the database user account, specified as a key=value pair.

  • mcs1, mcs2, and mcs3 are the names of the configured server objects, specified with the --servers option.

  • Other Module Parameters supported by readwritesplit in MaxScale 6.2 can also be specified.

Configure a Listener for the Read/Write Split Router

These instructions reference TCP port 3307. You can use a different TCP port. The TCP port used must not be bound by any other listener.

On the MaxScale node, use the maxctrl create listener command to configure MaxScale to use a listener for the Read/Write Split Router (readwritesplit):

$ maxctrl create listener query_router_service query_router_listener 3307 \
      --protocol=MariaDBClient

In this example:

  • query_router_service is the name of the service that uses the Read/Write Split Router (readwritesplit).

  • query_router_listener is the name of the new listener.

  • 3307 is the TCP port.

  • MariaDBClient is the protocol, specified with the --protocol option.

  • Other Module Parameters supported by listeners in MaxScale 6.2 can also be specified.

Start Services

To start the services and monitors, on the MaxScale node use maxctrl start services:

$ maxctrl start services

Next Step

Navigation in the procedure "Deploy ColumnStore Shared Local Storage Topology":

  • This page was step 7 of 9.