![Package Installation (CentOS, RHEL)
1. Remove existing MySQL server packages
2. Configure the Galera Cluster repository
Add a .repo file in /etc/yum.repos.d/:
[galera]
name = Galera
baseurl = http://releases.galeracluster.com/centos/7/x86_64
gpgkey = http://releases.galeracluster.com/GPG-KEY-galeracluster.com
gpgcheck = 1
(note distribution name and release number are specified)
1. Install Galera Cluster Packages
yum –y upgrade mysql-wsrep-shared-5.6
yum –y install galera-3 mysql-wsrep-5.6](https://image.slidesharecdn.com/codershipsgaleraclusterinstallationandquickstartwebinarmarch2016-160310092403/85/Codership-s-galera-cluster-installation-and-quickstart-webinar-march-2016-7-320.jpg)
Codership's galera cluster installation and quickstart webinar march 2016
- 1. Galera Cluster Installation And Quick Start Philip Stoev Codership Oy
- 2. 2 Codership Established 2007 (Galera development started) 3 co-founder engineers: Seppo Jaakola, CEO, Teemu Ollakka, CTO, Alex Yurchenko, architect Team have developed three MySQL cluster software earlier. Based on: http://www.dsn.jhu.edu/~yairamir/Yair_phd.pdf http://www.inf.usi.ch/faculty/pedone/Paper/199x/These-2090-Pedone.pdf Product: Galera Cluster for MySQL, open source Thousands of users in e-commerce, telecom, gaming, insurance, betting healthcare, media, marketing, advertising, travel, universities, software-as-service, Paas, Iaas, etc Galera Cluster is included and will be included in Linux and OpenStack distros
- 3. 3 Galera Cluster variants API MySQL Coderhips’s Galera Replication plugin API Percona Server API MariaDB merge merge Percona calls Galera Percona XtraDB Cluster Galera Cluster for MySQL by Codership MariaDB calls Galera MariaDB Galera Cluster or MariaDB Enterprise Cluster
- 4. Agenda • A very quick overview of Galera Cluster • Adding the Galera package repository • Installing packages • Creating a configuration file • Bootstrapping a 3-node cluster • Monitoring
- 5. Galera Cluster Overview Synchronous – each transaction is immediately replicated on all nodes at commit – no stale slaves Multi-Master – read from and write to any node – automatic transaction conflict detection Replication – a copy of the entire dataset is available on all nodes – new nodes can join automatically For MySQL – based on a modified version of MySQL (5.5, 5.6 with 5.7 coming up) – InnoDB storage engine
- 6. And more … • Recovers from node failures within seconds • Data consistency protections – avoids reading stale data – prevents unsafe data modifications • WAN support – nodes can be on different continents – end-to-end encryption – optimized communication with least latency
- 7. Package Installation (CentOS, RHEL) 1. Remove existing MySQL server packages 2. Configure the Galera Cluster repository Add a .repo file in /etc/yum.repos.d/: [galera] name = Galera baseurl = http://releases.galeracluster.com/centos/7/x86_64 gpgkey = http://releases.galeracluster.com/GPG-KEY-galeracluster.com gpgcheck = 1 (note distribution name and release number are specified) 1. Install Galera Cluster Packages yum –y upgrade mysql-wsrep-shared-5.6 yum –y install galera-3 mysql-wsrep-5.6
- 8. Preparing the System • Nodes should have identical hardware • Firewall ports to open: 3306, 4567, 4568, 4444 • Disable SELinux – a policy can be created and enabled later
- 9. The my.cnf Configuration File • All Galera configuration is in my.cnf • Keep the my.cnf files on all nodes identical • InnoDB settings are important optimize individual nodes as you normally would: – InnoDB buffer size – InnoDB log file size • Galera-specific settings: default_storage_engine=InnoDB binlog_format=ROW innodb_autoinc_lock_mode=2 wsrep_provider=/usr/lib64/galera-3/libgalera_smm.so wsrep_cluster_address="gcomm://node1,node2,node3... "
- 10. Bootstrap 1. Start first node with –wsrep-new-cluster: sudo service mysql start --wsrep-new-cluster 1. Confirm a single-node cluster: SHOW STATUS LIKE 'wsrep_%' | wsrep_cluster_status | Primary | | wsrep_cluster_size | 1 | 1. Start all other nodes normally sudo service mysql start 1. Confirm nodes have joined: SHOW STATUS LIKE 'wsrep_%' | wsrep_cluster_size | 3 |
- 11. Monitoring Traditional MySQL monitoring methods are used: • SHOW STATUS • SHOW PROCESSLIST • The MySQL error log – all Galera messages go there • Queries against INFORMATION_SCHEMA
- 12. SHOW STATUS • Node health variables: – wsrep_ready = ON – wsrep_cluster_size – wsrep_cluster_status = Primary – wsrep_local_status = Synced • Replication health variables: – wsrep_flow_control_paused < 0.05 – wsrep_local_bf_aborts + wsrep_local_cert_failures (do not forget periodic FLUSH STATUS)
- 13. SHOW PROCESSLIST • Queries to watch out for: – long “Query end” phase • replication takes place during that phase – long-running DDL • under default settings may block cluster
- 14. INFORMATION_SCHEMA • Avoid non-InnoDB tables: SELECT TABLE_SCHEMA, TABLE_NAME FROM INFORMATION_SCHEMA.TABLES WHERE ENGINE != 'InnoDB' AND TABLE_SCHEMA NOT IN ('mysql','performance_schema', 'information_schema'); • Avoid tables with no primary key: SELECT T.TABLE_SCHEMA, T.TABLE_NAME FROM information_schema.tables AS T WHERE (table_schema, table_name) NOT IN (SELECT table_schema, table_name FROM information_schema.table_constraints AS C WHERE T.table_name = C.table_name AND T.table_schema = C.table_schema ) AND table_schema NOT IN ('mysql','information_schema','performance_schema');