MariaDB Galera cluster PoC deployment using Uncloud

_mariadb-galera-cluster-uncloud.md

MariaDB Galera Cluster PoC with Uncloud

Install Uncloud CLI locally firts: https://uncloud.run/docs/getting-started/install-cli

# Create a 3-machine Uncloud cluster
uc machine init -n machine1 root@server1
uc machine add -n machine2 root@server2
uc machine add -n machine3 root@server3

# Deploy the first bootstrap node
uc deploy --profile bootstrap galera1-bootstrap

# Until compose configs implemented: https://github.com/psviderski/uncloud/issues/43
# Manually copy galera1,2,3.cnf to /var/lib/docker/volumes/galera1,2,3-conf/_data/galera.cnf on machines
# Restart the galera1-bootstrap service to pick up the new config
uc deploy --profile bootstrap galera1-bootstrap --recreate

# Deploy galera2 and galera3 services and wait for them to form the cluster
uc deploy galera2 galera3

# Remove the bootstrap node (using --wsrep-new-cluster) and replace it with a normal one
uc rm galera1-bootstrap
# Deploy all services, including the missing galera1
uc deploy

# Test on any machine
docker exec -it galera1-li6p mariadb -u root -psecret-password -e "
SELECT * FROM information_schema.GLOBAL_STATUS
WHERE VARIABLE_NAME IN ('wsrep_cluster_size', 'wsrep_cluster_status', 'wsrep_ready', 'wsrep_connected')
ORDER BY VARIABLE_NAME;"
+----------------------+----------------+
| VARIABLE_NAME        | VARIABLE_VALUE |
+----------------------+----------------+
| WSREP_CLUSTER_SIZE   | 3              |
| WSREP_CLUSTER_STATUS | Primary        |
| WSREP_CONNECTED      | ON             |
| WSREP_READY          | ON             |
+----------------------+----------------+

Now, your Uncloud services are able to communicate with the Galera Cluster via any if its nodes by using galera1:3306, galera2:3306, or galera3:3306 addresses. You can also deploy a Galera Load Balancer or HAProxy in front of the nodes to provide a single endpoint to the cluster.

compose.yaml

services:
  galera1-bootstrap:
    image: mariadb:12
    # This service is used only to bootstrap the cluster.
    command: --wsrep-new-cluster
    environment:
      MYSQL_ROOT_PASSWORD: secret-password
    volumes:
      - galera1-conf:/etc/mysql/conf.d:ro
      - galera1-data:/var/lib/mysql
    # Place the service on machine1
    x-machines: machine1
    profiles:
      - bootstrap

  galera1:
    image: mariadb:12
    environment:
      MYSQL_ROOT_PASSWORD: secret-password
    volumes:
      - galera1-conf:/etc/mysql/conf.d:ro
      - galera1-data:/var/lib/mysql
    # Place the service on machine1
    x-machines: machine1

  galera2:
    image: mariadb:12
    environment:
      MYSQL_ROOT_PASSWORD: secret-password
    volumes:
      - galera2-conf:/etc/mysql/conf.d:ro
      - galera2-data:/var/lib/mysql
    # Place the service on machine2
    x-machines: machine2

  galera3:
    image: mariadb:12
    environment:
      MYSQL_ROOT_PASSWORD: secret-password
    volumes:
      - galera3-conf:/etc/mysql/conf.d:ro
      - galera3-data:/var/lib/mysql
    # Place the service on machine3
    x-machines: machine3

volumes:
  galera1-data:
  galera1-conf:
  galera2-data:
  galera2-conf:
  galera3-data:
  galera3-conf:

galera1.cnf

[mysqld]
binlog_format=ROW
default-storage-engine=innodb
innodb_autoinc_lock_mode=2
bind-address=0.0.0.0

# Galera Cluster Configuration
wsrep_on=ON
wsrep_provider=/usr/lib/galera/libgalera_smm.so
wsrep_cluster_name="my_galera_cluster"
wsrep_cluster_address="gcomm://galera1-bootstrap,galera1,galera2,galera3"
wsrep_node_address="galera1"
wsrep_node_name="galera1"

# SST Configuration
wsrep_sst_method=mariabackup
wsrep_sst_auth=root:secret-password

galera2.cnf

[mysqld]
binlog_format=ROW
default-storage-engine=innodb
innodb_autoinc_lock_mode=2
bind-address=0.0.0.0

# Galera Cluster Configuration
wsrep_on=ON
wsrep_provider=/usr/lib/galera/libgalera_smm.so
wsrep_cluster_name="my_galera_cluster"
wsrep_cluster_address="gcomm://galera1,galera2,galera3"
wsrep_node_address="galera2"
wsrep_node_name="galera2"

# SST Configuration
wsrep_sst_method=mariabackup
wsrep_sst_auth=root:secret-password

galera3.cnf

[mysqld]
binlog_format=ROW
default-storage-engine=innodb
innodb_autoinc_lock_mode=2
bind-address=0.0.0.0

# Galera Cluster Configuration
wsrep_on=ON
wsrep_provider=/usr/lib/galera/libgalera_smm.so
wsrep_cluster_name="my_galera_cluster"
wsrep_cluster_address="gcomm://galera1,galera2,galera3"
wsrep_node_address="galera3"
wsrep_node_name="galera3"

# SST Configuration
wsrep_sst_method=mariabackup
wsrep_sst_auth=root:secret-password