CentOS 7
MariaDB 10.4.12

フォルダ構成

|--docker-compose.yml
|--dockerfiles
|  |--cluster
|  |--cluster.cnf
|  |--mariadb.repo

MariaDB 10.4でgaleraのバージョンが4になったため「galera」ではなく「galera-4」を指定

/dockerfile/cluster

FROM centos:7
ADD mariadb.repo /etc/yum.repos.d/mariadb.repo
RUN rpm --import https://yum.mariadb.org/RPM-GPG-KEY-MariaDB \
    && rpm --import https://www.centos.org/keys/RPM-GPG-KEY-CentOS-7 \
    && yum install -y -q MariaDB-server MariaDB-client galera-4 sudo 

ADD cluster.cnf /etc/my.cnf.d/my.cnf

galera4のパスが異なるため「wsrep_provider」の指定で、
「galera」のところを「galera-4」にしています

/dockerfile/cluster.cnf

[mysqld]
default_storage_engine=InnoDB
log-bin=/var/lib/mysql/mysql-bin-log
binlog_format=ROW
innodb_autoinc_lock_mode=2
innodb_doublewrite=1
transaction-isolation = READ-COMMITTED
innodb_flush_log_at_trx_commit=0

[galera]
wsrep_on=ON
wsrep_provider=/usr/lib64/galera-4/libgalera_smm.so
wsrep_cluster_name=DBCLUSTER
wsrep_sst_method=rsync
wsrep_slave_threads=2
wsrep_cluster_address=gcomm://node-1,node-2,node-3

/dockerfile/mariadb.repo

[mariadb]
name = MariaDB
baseurl = http://yum.mariadb.org/10.4.12/centos7-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1

docker-compose.yml

version: "3.7"
services:
  node-1:
    build:
      context: ./dockerfiles
      dockerfile: cluster
    ports:
      - "4001:3306"
    command: sudo -u mysql mysqld --wsrep-new-cluster

  node-2:
    build:
      context: ./dockerfiles
      dockerfile: cluster
    ports:
      - "4002:3306"
    links:
      - node-1
    command: sudo -u mysql mysqld

  node-3:
    build:
      context: ./dockerfiles
      dockerfile: cluster
    ports:
      - "4003:3306"
    links:
      - node-1
    command: sudo -u mysql mysqld

$ docker-compose up -d

$ docker-compose exec node-1 mysql -e "create database test_db"
$ docker-compose exec node-2 mysql -e "show databases"
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
| test_db            |
+--------------------+

$ docker-compose exec node-3 mysql -e "show databases"
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| test               |
| test_db            |
+--------------------+