MySQL HA with PaceMaker
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Pacemaker is a high availability cluster resource manager that can be used to provide high availability for MySQL databases. It monitors MySQL instances and replicates data between nodes using replication. If the primary MySQL node fails, Pacemaker detects the failure and fails over to the secondary node, bringing the MySQL service back online without downtime. Pacemaker manages shared storage and virtual IP failover to ensure connections are direct to the active MySQL node. It is important to monitor replication state and lag to ensure data consistency between nodes.
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MySQL HA with PaceMaker
- 1. MySQL HA with PaceMaker Kris Buytaert
- 2. Kris Buytaert Senior Linux and Open Source Consultant @inuits.be
- 4. I don't remember when I started using MySQL :)
- 5. Specializing in Automated , Large Scale Deployments , Highly Available infrastructures, since 2008 also known as “the Cloud”
- 6. Surviving the 10 th floor test
- 7. DevOp
- 8. In this presentation High Availability ?
- 11. Linux HA / Pacemaker
- 12. What is HA Clustering ? One service goes down => others take over its work IP address takeover, service takeover,
- 13. Not designed for high-performance
- 14. Not designed for high troughput (load balancing)
- 15. Does it Matter ? Downtime is expensive
- 16. You mis out on $$$
- 18. New users don't return
- 19. Lies, Damn Lies, and Statistics Counting nines (slide by Alan R)
- 20. The Rules of HA Keep it Simple
- 21. Keep it Simple
- 23. Complexity is the enemy of reliability
- 24. Test your HA setup
- 25. You care about ? Your data ? Consistent
- 26. Realitime
- 27. Eventual Consistent Your Connection Always
- 28. Most of the time
- 29. Eliminating the SPOF Find out what Will Fail Disks
- 30. Fans
- 31. Power (Supplies) Find out what Can Fail Network
- 32. Going Out Of Memory
- 33. Split Brain Communications failures can lead to separated partitions of the cluster
- 34. If those partitions each try and take control of the cluster, then it's called a split-brain condition
- 35. If this happens, then bad things will happen http://linux-ha.org/BadThingsWillHappen
- 36. Historical MySQL HA Replication 1 read write node
- 37. Multiple read only nodes
- 38. Application needed to be modified
- 40. DRBD
- 43. MySQL Proxy
- 44. MMM
- 45. Flipper
- 46. Data vs Connection DATA : Replication
- 48. Proxy
- 50. Shared Storage 1 MySQL instance
- 52. Stonith
- 53. $$$ 1+1 <> 2
- 54. Storage = SPOF
- 55. Split Brain :(
- 56. DRBD Distributed Replicated Block Device
- 57. In the Linux Kernel (as of very recent)
- 58. Usually only 1 mount Multi mount as of 8.X Requires GFS / OCFS2 Regular FS ext3 ...
- 59. Only 1 MySQL instance Active accessing data
- 60. Upon Failover MySQL needs to be started on other node
- 61. DRBD(2) What happens when you pull the plug of a Physical machine ? Minimal Timeout
- 62. Why did the crash happen ?
- 63. Is my data still correct ?
- 64. Innodb Consistency Checks ? Lengthy ?
- 65. Check your BinLog size
- 66. MySQL Cluster NDBD Shared-nothing architecture
- 69. Fast automatic fail-over of data nodes
- 71. Not suitable for all query patterns (multi-table JOINs, range scans)
- 72. Title Data
- 73. MySQL Cluster NDBD All indexed data needs to be in memory
- 74. Good and bad experiences Better experiences when using the API
- 75. Bad when using the MySQL Server Test before you deploy
- 76. Does not fit for all apps
- 77. How replication works Master server keeps track of all updates in the Binary Log Slave requests to read the binary update log
- 78. Master acts in a passive role, not keeping track of what slave has read what data Upon connecting the slaves do the following: The slave informs the master of where it left off
- 79. It catches up on the updates
- 80. It waits for the master to notify it of new update s
- 82. Two Slave Threads How does it work? The I/O thread connects to the master and asks for the updates in the master’s binary log
- 83. The I/O thread copies the statements to the relay log
- 84. The SQL thread implements the statements in the relay log Advantages Long running SQL statements don’t block log downloading
- 85. Allows the slave to keep up with the master better
- 86. In case of master crash the slave is more likely to have all statements
- 87. Replication commands Slave commands START|STOP SLAVE
- 88. RESET SLAVE
- 91. LOAD DATA FROM MASTER
- 92. LOAD TABLE tblname FROM MASTER Master commands SHOW MASTER STATUS
- 94. Show slave status Slave_IO_State: Waiting for master to send event Master_Host: 172.16.0.1 Master_User: repli Master_Port: 3306 Connect_Retry: 60 Master_Log_File: XMS-1-bin.000014 Read_Master_Log_Pos: 106 Relay_Log_File: XMS-2-relay.000033 Relay_Log_Pos: 251 Relay_Master_Log_File: XMS-1-bin.000014 Slave_IO_Running: Yes Slave_SQL_Running: Yes Replicate_Do_DB: xpol Replicate_Ignore_DB: Replicate_Do_Table: Replicate_Ignore_Table: Replicate_Wild_Do_Table: Replicate_Wild_Ignore_Table: Last_Errno: 0 Last_Error: Skip_Counter: 0 Exec_Master_Log_Pos: 106 Relay_Log_Space: 547 Until_Condition: None Until_Log_File: Until_Log_Pos: 0 Master_SSL_Allowed: No Master_SSL_CA_File: Master_SSL_CA_Path: Master_SSL_Cert: Master_SSL_Cipher: Master_SSL_Key: Seconds_Behind_Master: 0 Master_SSL_Verify_Server_Cert: No Last_IO_Errno: 0 Last_IO_Error: Last_SQL_Errno: 0 Last_SQL_Error: 1 row in set (0.00 sec)
- 95. Row vs Statement Pro Proven (around since MySQL 3.23)
- 97. Auditing of actual SQL statements
- 98. No primary key requirement for replicated tables Con Non-deterministic functions and UDFs Pro All changes can be replicated
- 99. Similar technology used by other RDBMSes
- 100. Fewer locks required for some INSERT, UPDATE or DELETE statements Con More data to be logged
- 101. Log file size increases (backup/restore implications)
- 102. Replicated tables require explicit primary keys
- 103. Possible different result sets on bulk INSERTs
- 104. Multi Master Replication Replicating the same table data both ways can lead to race conditions Auto_increment, unique keys, etc.. could cause problems If you write them 2x Both nodes are master
- 105. Both nodes are slave
- 106. Write in 1 get updates on the other M|S M|S
- 107. MySQL Proxy Man in the middle
- 108. Decides where to connect to LUA Write rules to Redirect traffic
- 109. Master Slave & Proxy Split Read and Write Actions
- 110. No Application change required
- 111. Sends specific queries to a specific node
- 112. Based on Customer
- 113. User
- 114. Table
- 115. Availability
- 116. MySQL Proxy Your new SPOF
- 117. Make your Proxy HA too ! Heartbeat OCF Resource
- 118. Breaking Replication If the master and slave gets out of sync
- 119. Updates on slave with identical index id Check error log for disconnections and issues with replication
- 120. Monitor your Setup Not just connectivity
- 121. Also functional Query data
- 122. Check resultset is correct Check replication MaatKit
- 123. OpenARK
- 124. Pulling Traffic Eg. for Cluster, MultiMaster setups DNS
- 125. Advanced Routing
- 126. LVS
- 127. Or the upcoming slides
- 128. MMM Multi-Master Replication Manager for MySQL Perl scripts to perform monitoring/failover and management of MySQL master-master replication configurations Balance master / slave configs based on replication state Map Virtual IP to the Best Node http://mysql-mmm.org/
- 129. Flipper Flipper is a Perl tool for managing read and write access pairs of MySQL servers
- 130. master-master MySQL Servers
- 131. Clients machines do not connect "directly" to either node instead,
- 132. One IP for read,
- 133. One IP for write.
- 134. Flipper allows you to move these IP addresses between the nodes in a safe and controlled manner.
- 136. Linux-HA PaceMaker Plays well with others
- 137. Manages more than MySQL
- 138. ...v3 .. don't even think about the rest anymore
- 140. Heartbeat Heartbeat v1 Max 2 nodes
- 142. Monitoring using “mon” Heartbeat v2 XML usage was a consulting opportunity
- 143. Stability issues
- 144. Forking ?
- 145. Pacemaker Architecture Stonithd : The Heartbeat fencing subsystem.
- 146. Lrmd : Local Resource Management Daemon. Interacts directly with resource agents (scripts).
- 147. pengine Policy Engine. Computes the next state of the cluster based on the current state and the configuration.
- 148. cib Cluster Information Base. Contains definitions of all cluster options, nodes, resources, their relationships to one another and current status. Synchronizes updates to all cluster nodes.
- 149. crmd Cluster Resource Management Daemon. Largely a message broker for the PEngine and LRM, it also elects a leader to co-ordinate the activities of the cluster.
- 150. openais messaging and membership layer.
- 151. heartbeat messaging layer, an alternative to OpenAIS.
- 152. ccm Short for Consensus Cluster Membership. The Heartbeat membership layer.
- 153. Pacemaker ? Not a fork
- 154. Only CRM Code taken out of Heartbeat
- 155. As of Heartbeat 2.1.3 Support for both OpenAIS / HeartBeat
- 156. Different Release Cycles as Heartbeat
- 157. Heartbeat, OpenAis ? Both Messaging Layers
- 159. OpenAIS
- 161. OpenAIS has heisenbugs :(
- 162. Heartbeat maintenance taken over by LinBit
- 163. CRM Detects which layer
- 164. or OpenAIS Heartbeat Pacemaker Cluster Glue
- 165. Configuring Heartbeat /etc/ha.d/ha.cf Use crm = yes /etc/ha.d/authkeys
- 166. Configuring Heartbeat heartbeat::hacf {"clustername": hosts => ["host-a","host-b"], hb_nic => ["bond0"], hostip1 => ["10.0.128.11"], hostip2 => ["10.0.128.12"], ping => ["10.0.128.4"], } heartbeat::authkeys {"ClusterName": password => “ClusterName ", } http://github.com/jtimberman/puppet/tree/master/heartbeat/
- 168. Heartbeat resource (+status)
- 169. OCF (Open Cluster FrameWork) (+monitor)
- 170. Clones (don't use in HAv2)
- 171. Multi State Resources
- 172. The MySQL Resource OCF Clone Where do you hook up the IP ? Multi State But we have Master Master replication Meta Resource Dummy resource that can monitor Connection
- 173. Replication state
- 174. ....
- 175. CRM Cluster Resource Manager
- 176. Keeps Nodes in Sync
- 177. XML Based
- 178. cibadm
- 179. Cli manageable
- 180. Crm configure property $id="cib-bootstrap-options" stonith-enabled="FALSE" no-quorum-policy=ignore start-failure-is-fatal="FALSE" rsc_defaults $id="rsc_defaults-options" migration-threshold="1" failure-timeout="1" primitive d_mysql ocf:local:mysql op monitor interval="30s" params test_user="sure" test_passwd="illtell" test_table="test.table" primitive ip_db ocf:heartbeat:IPaddr2 params ip="172.17.4.202" nic="bond0" op monitor interval="10s" group svc_db d_mysql ip_db commit
- 181. Hardware Cluster Stack Resource MySQL Replication Adding MySQL to the stack Node A Node B HeartBeat Pacemaker “ MySQLd” “ MySQLd” Service IP MySQL
- 182. Pitfalls & Solutions Monitor, Replication state
- 184. OpenARK
- 185. Conclusion Plenty of Alternatives
- 186. Think about your Data
- 187. Think about getting Queries to that Data
- 188. Complexity is the enemy of reliability
- 189. Keep it Simple
- 190. Monitor inside the DB
- 191. ` Kris Buytaert < [email_address] > Further Reading http://www.krisbuytaert.be/blog/ http://www.inuits.be/ http://www.virtualization.com/ http://www.oreillygmt.com/ ? !