Today’s article we shall cover how to set up a highly available database cluster with load balancing using MariaDB Galera cluster and ProxySQL. Database availability is a requirement for production environments running database systems. Load balancing is also key if you want to attain a high level of efficiency.
If you are looking for a solution that will guarantee you both high availability and load balancing, then you might just choose to use this option.
MariaDB Galera Cluster is a synchronous multi-master cluster for MariaDB with support for XtraDB/InnoDB storage engines. It has the following top features.
- It provides active-active multi-master topology
- You can read and write to any cluster node
- It has an automatic node joining
- Automatic membership control, failed nodes drop from the cluster
- Has true parallel replication, on row level
- Direct client connections
ProxySQL is a MySQL proxy server that used as an intermediary between the Galera cluster and the applications trying to access the cluster.
Setup Galera Cluster on Ubuntu 20.04
The steps below will cover how to setup galera cluster on three Ubuntu 20.04 hosts.
We assume that you have access to the three hosts with sudo rights.
Below is how my setup is:
| Server | Hostname | IP Address |
| DB 1 | node1 | 172.20.5.200 |
| DB 2 | node2 | 172.20.5.201 |
| DB3 | node3 | 172.20.5.202 |
Step 1: Update servers
Update the servers and reboot
sudo apt update && sudo apt -y upgrade
sudo rebootStep 2: Setup Hostnames
Configure static hostnames on each of the three servers for DNS reachability.
$ sudo vim /etc/hosts
172.20.5.200 node1.computingforgeeks.com node1
172.20.5.201 node2.computingforgeeks.com node2
172.20.5.202 node3.computingforgeeks.com node3Step 3: Install MariaDB on all nodes
Install the latest version of MariaDB with the commands below:
sudo apt update
sudo apt -y install mariadb-server mariadb-clientConfigure MariaDB for first use by running the command below, then run through the configuration appropriately.
$ sudo mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
SERVERS IN PRODUCTION USE! PLEASE READ EACH STEP CAREFULLY!
In order to log into MariaDB to secure it, we'll need the current
password for the root user. If you've just installed MariaDB, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.
Enter current password for root (enter for none):
OK, successfully used password, moving on...
Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.
Set root password? [Y/n] y
New password:
Re-enter new password:
Password updated successfully!
Reloading privilege tables..
... Success!
By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them. This is intended only for testing, and to make the installation
go a bit smoother. You should remove them before moving into a
production environment.
Remove anonymous users? [Y/n] y
... Success!
Normally, root should only be allowed to connect from 'localhost'. This
ensures that someone cannot guess at the root password from the network.
Disallow root login remotely? [Y/n] y
... Success!
By default, MariaDB comes with a database named 'test' that anyone can
access. This is also intended only for testing, and should be removed
before moving into a production environment.
Remove test database and access to it? [Y/n] y
- Dropping test database...
... Success!
- Removing privileges on test database...
... Success!
Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.
Reload privilege tables now? [Y/n] y
... Success!
Cleaning up...
All done! If you've completed all of the above steps, your MariaDB
installation should now be secure.
Thanks for using MariaDB!Test connection to each of the databases by running the command below:
$ mysql -u root -pYou will be prompted to input a password that you had setup in the previous step.
Step 4: Configure Galera Cluster
The next step is to configure galera cluster on our three MariaDB hosts. Comment the bind line on the file /etc/mysql/mariadb.conf.d/50-server.cnf which binds MariaDB service to 127.0.0.1
$ sudo vim /etc/mysql/mariadb.conf.d/50-server.cnf
#bind-address = 127.0.0.1Step Configure First Node
Add the following content to the MariaDB configuration file. Remember to modify the hostname at “wsrep_node_address” to the hostname or IP of your first host.
$ sudo vim /etc/mysql/mariadb.conf.d/50-server.cnf
[galera]
wsrep_on = ON
wsrep_cluster_name = "MariaDB Galera Cluster"
wsrep_provider = /usr/lib/galera/libgalera_smm.so
wsrep_cluster_address = "gcomm://node1,node2,node3"
binlog_format = row
default_storage_engine = InnoDB
innodb_autoinc_lock_mode = 2
bind-address = 0.0.0.0
wsrep_node_address="node1"Initialize galera cluster and restart MariaDB
sudo galera_new_cluster
sudo systemctl restart mariadb Configure Galera nodes (node2 & node3)
Add the following configuration for node2 and node3 respectively:
Node2:
$ sudo vim /etc/mysql/mariadb.conf.d/50-server.cnf
[galera]
wsrep_on = ON
wsrep_cluster_name = "MariaDB Galera Cluster"
wsrep_provider = /usr/lib/galera/libgalera_smm.so
wsrep_cluster_address = "gcomm://node1,node2,node3"
binlog_format = row
default_storage_engine = InnoDB
innodb_autoinc_lock_mode = 2
bind-address = 0.0.0.0
wsrep_node_address="node2"Node3:
$ sudo vim /etc/mysql/mariadb.conf.d/50-server.cnf
[galera]
wsrep_on = ON
wsrep_cluster_name = "MariaDB Galera Cluster"
wsrep_provider = /usr/lib/galera/libgalera_smm.so
wsrep_cluster_address = "gcomm://node1,node2,node3"
binlog_format = row
default_storage_engine = InnoDB
innodb_autoinc_lock_mode = 2
bind-address = 0.0.0.0
wsrep_node_address="node3"Restart MariaDB service on node2 and node3
systemctl restart mariadbStep 5: Validate Galera Settings
Login to any of the three nodes as the root user, then confirm that the cluster settings are OK.
$ mysql -u root -p
Enter password:
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 35
Server version: 10.5.9-MariaDB-1:10.5.9+maria~focal mariadb.org binary distribution
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]>Check status
MariaDB [(none)]> show status like 'wsrep_%';
+-------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------+
| Variable_name | Value |
+-------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------+
| wsrep_local_state_uuid | c2e29a95-a81f-11eb-a1fc-237e9071c44f |
| wsrep_protocol_version | 10 |
| wsrep_last_committed | 7 |
| wsrep_replicated | 0 |
| wsrep_replicated_bytes | 0 |
| wsrep_repl_keys | 0 |
| wsrep_repl_keys_bytes | 0 |
| wsrep_repl_data_bytes | 0 |
| wsrep_repl_other_bytes | 0 |
| wsrep_received | 7 |
| wsrep_received_bytes | 690 |
| wsrep_local_commits | 0 |
| wsrep_local_cert_failures | 0 |
| wsrep_local_replays | 0 |
| wsrep_local_send_queue | 0 |
| wsrep_local_send_queue_max | 1 |
| wsrep_local_send_queue_min | 0 |
| wsrep_local_send_queue_avg | 0 |
| wsrep_local_recv_queue | 0 |
| wsrep_local_recv_queue_max | 2 |
| wsrep_local_recv_queue_min | 0 |
| wsrep_local_recv_queue_avg | 0.142857 |
| wsrep_local_cached_downto | 1 |
| wsrep_flow_control_paused_ns | 0 |
| wsrep_flow_control_paused | 0 |
| wsrep_flow_control_sent | 0 |
| wsrep_flow_control_recv | 0 |
| wsrep_flow_control_active | false |
| wsrep_flow_control_requested | false |
| wsrep_cert_deps_distance | 0 |
| wsrep_apply_oooe | 0 |
| wsrep_apply_oool | 0 |
| wsrep_apply_window | 0 |
| wsrep_commit_oooe | 0 |
| wsrep_commit_oool | 0 |
| wsrep_commit_window | 0 |
| wsrep_local_state | 4 |
| wsrep_local_state_comment | Synced |
| wsrep_cert_index_size | 0 |
| wsrep_causal_reads | 0 |
| wsrep_cert_interval | 0 |
| wsrep_open_transactions | 0 |
| wsrep_open_connections | 0 |
| wsrep_incoming_addresses | AUTO,AUTO,AUTO |
| wsrep_cluster_weight | 3 |
| wsrep_desync_count | 0 |
| wsrep_evs_delayed | |
| wsrep_evs_evict_list | |
| wsrep_evs_repl_latency | 0/0/0/0/0 |
| wsrep_evs_state | OPERATIONAL |
| wsrep_gcomm_uuid | e4af838d-a824-11eb-95d0-72f816b84c68 |
| wsrep_gmcast_segment | 0 |
| wsrep_applier_thread_count | 1 |
| wsrep_cluster_capabilities | |
| wsrep_cluster_conf_id | 3 |
| wsrep_cluster_size | 3 |
| wsrep_cluster_state_uuid | c2e29a95-a81f-11eb-a1fc-237e9071c44f |
| wsrep_cluster_status | Primary |
| wsrep_connected | ON |
| wsrep_local_bf_aborts | 0 |
| wsrep_local_index | 2 |
| wsrep_provider_capabilities | :MULTI_MASTER:CERTIFICATION:PARALLEL_APPLYING:TRX_REPLAY:ISOLATION:PAUSE:CAUSAL_READS:INCREMENTAL_WRITESET:UNORDERED:PREORDERED:STREAMING:NBO: |
| wsrep_provider_name | Galera |
| wsrep_provider_vendor | Codership Oy <[email protected]> |
| wsrep_provider_version | 4.7(ree4f10fc) |
| wsrep_ready | ON |
| wsrep_rollbacker_thread_count | 1 |
| wsrep_thread_count | 2 |
+-------------------------------+------------------------------------------------------------------------------------------------------------------------------------------------+
68 rows in set (0.002 sec)
MariaDB [(none)]> Confirm that we have a cluster size of 3 under:
wsrep_cluster_size 3We can create a test database on any of the nodes and check its availability on the other nodes.
root@node1:~# mysql -u root -p
Enter password:
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 49
Server version: 10.5.9-MariaDB-1:10.5.9+maria~focal mariadb.org binary distribution
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]> create database test1;
Query OK, 1 row affected (0.003 sec)
# node2 and node3
root@node2:~# mysql -u root -p
Enter password:
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 45
Server version: 10.5.9-MariaDB-1:10.5.9+maria~focal mariadb.org binary distribution
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test1 |
+--------------------+
4 rows in set (0.001 sec)
root@node3:~# mysql -u root -p
Enter password:
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 46
Server version: 10.5.9-MariaDB-1:10.5.9+maria~focal mariadb.org binary distribution
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test1 |
+--------------------+
4 rows in set (0.001 sec)This confirms that the database created on node1 is replicated across the cluster.
Step 6: Install ProxySQL server
With a working Galera cluster, we need to setup a ProxySQL server that will distribute traffic to the three nodes equally. ProxySQL can run on the server that has the application or run as an independent server. This article will cover how to set it up on an independent Debian/CentOS host with the steps below:
Debian / Ubuntu
Add ProxySQL repository:
sudo apt install -y lsb-release
wget -O - 'https://repo.proxysql.com/ProxySQL/repo_pub_key' | sudo apt-key add -
echo deb https://repo.proxysql.com/ProxySQL/proxysql-2.3.x/$(lsb_release -sc)/ ./ | tee /etc/apt/sources.list.d/proxysql.listInstall ProxySQL:
sudo apt update
sudo apt install proxysql mysql-clientCentOS/RedHat
Add ProxySQL repo
sudo tee /etc/yum.repos.d/proxysql.repo<<EOF
[proxysql_repo]
name= ProxySQL YUM repository
baseurl=https://repo.proxysql.com/ProxySQL/proxysql-2.3.x/centos/\$releasever
gpgcheck=1
gpgkey=https://repo.proxysql.com/ProxySQL/repo_pub_key
EOFInstall ProxySQL
sudo yum install proxysql mysql-clientStep 7: Configure ProxySQL on Ubuntu 20.04
After a successful installation, start and enable the service on your host.
sudo systemctl enable --now proxysqlThe next step is to configure ProxySQL through admin interface. The admin interface allows you to save configuration without restarting the proxy. This is achieved through SQL queries to the admin database.
To connect to ProxySQL admin interface, we need a mysql-client. The admin interface runs locally on port 6032 and the default username/password is admin/admin.
$ mysql -u admin -padmin -h 127.0.0.1 -P6032 --prompt='Admin> 'root@proxy:~# mysql -u admin -padmin -h 127.0.0.1 -P6032 --prompt='Admin> '
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.5.30 (ProxySQL Admin Module)
Copyright (c) 2000, 2021, Oracle and/or its affiliates.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
Admin>
Change the default password for security reasons: