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Overview
Maxscale is proxy that extends the high availability of MariaDB. MariaDB MaxScale is an advanced database proxy, firewall, and query router. MaxScale is a component of MariaDB Platform. MaxScale is compatible with MariaDB Enterprise Server, MariaDB ColumnStore, and MariaDB Community Server. Let's imagine the following configuration:
- 192.168.10.101 node1
- 192.168.10.102 node2
- 192.168.10.103 node3
- 192.168.10.104 node4
The Cluster will be configured as follows:
Maxscale:
- node1
Galera Cluster:
- node2
- node3
- node4
Setting up
To set up we have to install the packages and configure the repositories. Do that on all nodes in the cluster. In our case on all 4:
Repo Config
[root@node1 ~]# curl -sS https://downloads.mariadb.com/MariaDB/mariadb_repo_setup | sudo bash [warning] Found existing file at /etc/yum.repos.d/mariadb.repo. Moving to /etc/yum.repos.d/mariadb.repo.old_1 [info] Repository file successfully written to /etc/yum.repos.d/mariadb.repo [info] Adding trusted package signing keys... [info] Successfully added trusted package signing keys [root@node1 ~]#
Install MariaDB Server
After that we can install the Maria DB
Install MariaDB
[root@node1 ~]# yum -y install MariaDB-server Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: ftp.cvut.cz * extras: ftp.cvut.cz * updates: ftp.cvut.cz mariadb-main | 2.9 kB 00:00:00 mariadb-maxscale | 2.4 kB 00:00:00 mariadb-tools | 2.9 kB 00:00:00 (1/3): mariadb-maxscale/7/x86_64/primary_db | 7.1 kB 00:00:00 (2/3): mariadb-tools/7/x86_64/primary_db | 14 kB 00:00:00 (3/3): mariadb-main/7/x86_64/primary_db | 70 kB 00:00:00 Resolving Dependencies --> Running transaction check ---> Package MariaDB-server.x86_64 0:10.5.6-1.el7.centos will be installed --> Processing Dependency: perl(DBI) for package: MariaDB-server-10.5.6-1.el7.centos.x86_64 --> Processing Dependency: libaio.so.1(LIBAIO_0.1)(64bit) for package: MariaDB-server-10.5.6-1.el7.centos.x86_64 --> Processing Dependency: MariaDB-client for package: MariaDB-server-10.5.6-1.el7.centos.x86_64 --> Processing Dependency: perl(Data::Dumper) for package: MariaDB-server-10.5.6-1.el7.centos.x86_64 --> Processing Dependency: galera-4 for package: MariaDB-server-10.5.6-1.el7.centos.x86_64 --> Processing Dependency: MariaDB-common for package: MariaDB-server-10.5.6-1.el7.centos.x86_64 --> Processing Dependency: lsof for package: MariaDB-server-10.5.6-1.el7.centos.x86_64 --> Processing Dependency: libaio.so.1(LIBAIO_0.4)(64bit) for package: MariaDB-server-10.5.6-1.el7.centos.x86_64 Installed: MariaDB-compat.x86_64 0:10.5.6-1.el7.centos MariaDB-server.x86_64 0:10.5.6-1.el7.centos Dependency Installed: MariaDB-client.x86_64 0:10.5.6-1.el7.centos MariaDB-common.x86_64 0:10.5.6-1.el7.centos boost-program-options.x86_64 0:1.53.0-28.el7 galera-4.x86_64 0:26.4.5-1.el7.centos libaio.x86_64 0:0.3.109-13.el7 lsof.x86_64 0:4.87-6.el7 pcre2.x86_64 0:10.23-2.el7 perl-Compress-Raw-Bzip2.x86_64 0:2.061-3.el7 perl-Compress-Raw-Zlib.x86_64 1:2.061-4.el7 perl-DBI.x86_64 0:1.627-4.el7 perl-Data-Dumper.x86_64 0:2.145-3.el7 perl-IO-Compress.noarch 0:2.061-2.el7 perl-Net-Daemon.noarch 0:0.48-5.el7 perl-PlRPC.noarch 0:0.2020-14.el7 socat.x86_64 0:1.7.3.2-2.el7 Replaced: mariadb-libs.x86_64 1:5.5.60-1.el7_5
Install MariaDB Client
Install MariaDB Client
Install MariaDB Client
[root@node1 ~]# yum -y install MariaDB-client Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: ftp.cvut.cz * extras: ftp.cvut.cz * updates: ftp.cvut.cz Package MariaDB-client-10.5.6-1.el7.centos.x86_64 already installed and latest version Nothing to do [root@node1 ~]#
Setup Galera Cluster
To setup the Galera Cluster, we have to edit the configuration for MariaDB (/etc/my.cnf.d/server.cnf) on: node2, node3 and node4. That configuration is used only for testing, for production, there will be WAY MORE configuration parameters:
Galera Configuration
[galera] # Mandatory settings wsrep_on=ON wsrep_provider=/usr/lib64/galera/libgalera_smm.so wsrep_cluster_address="gcomm://192.168.10.102,192.168.10.103,192.168.10.104" binlog_format=row default_storage_engine=InnoDB innodb_autoinc_lock_mode=2
The description of these parameters you can check below:
- wsrep_on – This is a session level flag to indicate of the operations we are performing will be replicated, much like how the sql_log_bin setting controls if statements are written to the binlog when using MariaDB Replication. The default of this is ON, but we set it anyway, to be safe.
- wsrep_provider – This points to the location of the Galera library. Although MariaDB is set up to use Galera from scratch, you still have to point to the Galera library. This is installed as part of the MariaDB-Server installation above.
- wsrep_cluster_address – This is where we define the nodes in the cluster, in general you don’t need to list all nodes and new nodes can be added later to a running cluster, but in this case we know what the cluster looks like so we set it up here.
- binlog_format – Although the binlog, in terms of the actual binlog files, isn’t used by Galera, the binlog facility is, and for Galera to work you have to run with row format in the binlog.
- default_storage_engine – Again, this is the default value, but just to be safe let’s set up MariaDB Server to explicitly use the InnoDB Storage Engine, which is the only engine supported by Galera.
- innodb_autoinc_lock_mode – This setting defines how the InnoDB Storage Engine generates values for auto_increment columns. Using mode 2 here is very important for Galera to work properly. In short, mode 2 cause much less locking during auto_increment generation and hence doesn’t interfere with other locking. Values other than 2 can cause deadlocking and other issues with Galera.