Table of Contents

1. Challenge

   Configure the Initial Cluster Containers

   Create the container:

   lxc launch ubuntu:18.04 galera01
   

   Access the container and run initial updates:

   lxc exec galera01 -- bash
   apt update
   apt upgrade
   

   Add the MariaDB repository:

   apt-key adv --recv-keys --keyserver hkp://keyserver.ubuntu.com:80 0xF1656F24C74CD1D8
   add-apt-repository 'deb [arch=amd64,ppc64el] http://ftp.utexas.edu/mariadb/repo/10.1/ubuntu bionic main'
   apt update
   

   Install MariaDB:

   apt install mariadb-server -y
   

   Run mysql_secure_installation:

   mysql_secure_installation
   

   Update the innodb_buffer_pool_size for the MariaDB configuration:

   vim /etc/mysql/my.cnf
   

   innodb_buffer_pool_size = 16M
   

   Configure the firewall:

   ufw enable
   ufw allow 3306/tcp
   ufw allow 4444/tcp
   ufw allow 4567/tcp
   ufw allow 4568/tcp
   ufw allow 4567/udp
   ufw status
   

   Exit the container and take a snapshot:

   exit
   lxc snapshot galera01 init
   

   Create the two additional containers and start them:

   lxc copy galera01/init galera02
   lxc copy galera01/init galera03
   lxc start galera02
   lxc start galera03
   

2. Challenge

   Configure Galera

   View all containers and make note of each IP address:

   lxc list
   

   Open the galera.cnf configuration in the cloud_user's home directory and update the wsrep_cluster_address to list all IP addresses. Update the wsrep_node_address and wsrep_node_name for the galera01 node:

   vim galera.cnf
   

   [mysqld]
   binlog_format=ROW
   default-storage-engine=innodb
   innodb_autoinc_lock_mode=2
   bind-address=0.0.0.0
   
   # Galera Provider Configuration
   wsrep_on=ON
   wsrep_provider=/usr/lib/galera/libgalera_smm.so
   # Galera Cluster Configuration
   wsrep_cluster_name="galera_cluster"
   wsrep_cluster_address="gcomm://<IP_ADDRESS>,<IP_ADDRESS>,<IP_ADDRESS>"
   
   # Galera Synchronization Configuration
   wsrep_sst_method=rsync
   
   # Galera Node Configuration
   wsrep_node_address="<IP_ADDRESS>"
   wsrep_node_name="galera01"
   

   Push to the first container:

   lxc file push galera.cnf galera01/etc/mysql/conf.d/galera.cnf
   

   Update the configuration file again, changing the address and name so it works with galera02:

   vim galera.cnf
   

   wsrep_node_address="<IP_ADDRESS>"
   wsrep_node_name="galera02"
   

   lxc file push galera.cnf galera02/etc/mysql/conf.d/galera.cnf
   

   Do the same for galera03:

   vim galera.cnf
   

   wsrep_node_address="<IP_ADDRESS>"
   wsrep_node_name="galera03"
   

   lxc file push galera.cnf galera03/etc/mysql/conf.d/galera.cnf
   

3. Challenge

   Start the Cluster

   Stop MySQL on all nodes:

   lxc exec galera01 -- systemctl stop mysql
   lxc exec galera02 -- systemctl stop mysql
   lxc exec galera03 -- systemctl stop mysql
   

   Start the Galera cluster:

   lxc exec galera01 -- galera_new_cluster
   lxc exec galera02 -- systemctl start mysql
   lxc exec galera03 -- systemctl start mysql
   

   To confirm that everything is working, view the cluster size on all containers:

   lxc exec galera01 -- mysql -u root -p -e "show status like 'wsrep_cluster_size'"
   lxc exec galera02 -- mysql -u root -p -e "show status like 'wsrep_cluster_size'"
   lxc exec galera03 -- mysql -u root -p -e "show status like 'wsrep_cluster_size'"