MySQL master-master replication with Galera

1. GaleraGalera
Master-MasterMaster-Master
ReplicationReplication
Marian HackMan Marinov <mm@1h.com>

2. What is the BinaryLog?
UPDATE t1 SET count=100 WHERE id=100UPDATE t1 SET count=100 WHERE id=100
CLIENTCLIENT

3. What is the BinaryLog?
UPDATE t1 SET count=100 WHERE id=100UPDATE t1 SET count=100 WHERE id=100
CLIENTCLIENT

4. What is the BinaryLog?
UPDATE t1 SET count=100 WHERE id=100UPDATE t1 SET count=100 WHERE id=100
CLIENTCLIENT
SUCCESS

5. What is the BinaryLog?
UPDATE t1 SET count=100 WHERE id=100UPDATE t1 SET count=100 WHERE id=100
CLIENTCLIENT
SUCCESS

6. Types of Replication
● STATEMENT
● ROW
● MIXED
● Master-Slave
● Master-Master

7. Types of Replication
● STATEMENT
UPDATE t1 SET count=100 WHERE id=100;UPDATE t1 SET count=100 WHERE id=100;
INSERT INTO t1 VALUES (102, 1);INSERT INTO t1 VALUES (102, 1);

8. Types of Replication
● ROW
table t1 change:table t1 change:
ROW id=100 count=100ROW id=100 count=100
table t1 change:table t1 change:
add row with id=102, count=1add row with id=102, count=1

9. Types of Replication
● MIXED
UPDATE t1 SET count=100 WHERE id=100;UPDATE t1 SET count=100 WHERE id=100;
table t1 change:table t1 change:
ROW id=100 count=100ROW id=100 count=100
INSERT INTO t1 VALUES (102, 1);INSERT INTO t1 VALUES (102, 1);
table t1 change:table t1 change:
add row with id=102, count=1add row with id=102, count=1

10. What is Galera
●
Write set replication - WSREPWrite set replication - WSREP
●
Global Transaction ID - GTIDGlobal Transaction ID - GTID

11. What is Galera
●
Write set replication - WSREPWrite set replication - WSREP
UPDATE t1 SET count=100 WHERE id=100;UPDATE t1 SET count=100 WHERE id=100;
INSERT INTO t1 VALUES (102, 1);INSERT INTO t1 VALUES (102, 1);
Write setWrite set

12. What is Galera
●
Write set replication - WSREPWrite set replication - WSREP
UPDATE t1 SET count=100 WHERE id=100;UPDATE t1 SET count=100 WHERE id=100;
INSERT INTO t1 VALUES (102, 1);INSERT INTO t1 VALUES (102, 1);
Write setWrite set
GTID: 318e70bb-4ba2-4707-aa5f-20cf44c3d367GTID: 318e70bb-4ba2-4707-aa5f-20cf44c3d367

13. What is Galera
●
Write set replication - WSREPWrite set replication - WSREP
UPDATE t1 SET count=100 WHERE id=100;UPDATE t1 SET count=100 WHERE id=100;
INSERT INTO t1 VALUES (102, 1);INSERT INTO t1 VALUES (102, 1);
Write setWrite set
GTID: 318e70bb-4ba2-4707-aa5f-20cf44c3d367GTID: 318e70bb-4ba2-4707-aa5f-20cf44c3d367
Certification based replication???Certification based replication???

14. ● WSREP XXX-XXX
– certificate that it can proceed
– check based on table's primary key

15. How is it implemented?

16. How is it implemented?

17. How is it implemented?
● WSREP plugin
– backing up data
● logs and files
– conns between nodes
– generating GTIDs
– certification of WSETs
WSREP

18. How is it implemented?

19. Node states

20. ● State Snapshot Transfer (SST)
– Logical - mysqldump
– Physical
● rsync/rsync_wan
● xtrabackup
wsrep_sst_method=xtrabackupv2
● Incremental State Transfer (IST)
5a76ef62-30ec-11e1-0800-dba504cf2aab:197222
5a76ef62-30ec-11e1-0800-dba504cf2aab:201913
– Write-set cache (GCache)

21. Requirements
● binlog_format=ROW
● Storage engine InnoDB/XtraDB
● All tables should have a primary key

22. Setup
/etc/yum.repos.d/galera.repo
[galera]
name = Galera
baseurl =
http://releases.galeracluster.com/centos/6/x86_64
gpgkey = http://releases.galeracluster.com/GPG-
KEY-galeracluster.com
gpgcheck = 1

23. Setup
yum install
Percona-XtraDB-Cluster-server
Percona-XtraDB-Cluster-client
Percona-XtraDB-Cluster-galera-3.x86_64
galera
socat
pv
pigz
nc

24. Setup
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
binlog_format=ROW
bind-address=0.0.0.0
default_storage_engine=innodb
innodb_autoinc_lock_mode=2
innodb_flush_log_at_trx_commit=0
innodb_buffer_pool_size=122M

25. Setup
wsrep_provider=/usr/lib64/galera3/libgalera_smm.so
wsrep_provider_options="gcache.size=300M;gcache.p
age_size=300M"
wsrep_cluster_name="example_cluster"
wsrep_cluster_address="gcomm://10.19.1.8,10.19.1.9"
wsrep_sst_method=xtrabackup-v2
wsrep_sst_auth="root:ensurethehighest"

26. Setup
[sst]
progress=/var/log/mysql/sst.log
streamfmt=xbstream
transferfmt=socat
encrypt=2
encrypt-algo=AES256
tkey=/etc/mysql/key.pem
tcert=/etc/mysql/cert.pem
compressor="pigz -6"
decompressor="pigz -d"

27. First start
# mysql_install_db
# service mysql start --wsrep-new-cluster

28. Adding new node
● Add GRANTs for the new machine
– GRANT ALL ON *.* TO 'root'@'10.19.1.10' IDENTIFIED BY 'ensurethehighest';
● Copy the my.cnf from another node
● Fix the node_name and node_address
● Add the IP of the local node to cluster_address
● Start MySQL on the new node
● After the sync is done and the new node is in the cluster
– update the cluster_address in the configuration of the other nodes
– update the cluster_address in the running mysql instances:
mysql> set global wsrep_cluster_address =
'gcomm://10.19.1.8,10.19.1.9,10.19.1.10';

29. Arbitrator
# chkconfig garb on
# cat /etc/sysconfig/garb
GALERA_NODES="10.19.1.8:4567
10.19.1.9:4567 10.19.1.10:4567"
GALERA_GROUP="gp_cluster"
# /etc/init.d/garb restart

30. QUESTIONS???QUESTIONS???
Marian HackMan Marinov <mm@1h.com>