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MySQL InnoDB Cluster & Group Replication in aNutshell: Hands-On Tutorial

Percona Live Europe 2017 - Dublin

Frédéric Descamps - MySQL Community Manager - OracleKenny Gryp - MySQL Practice Manager - Percona

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Safe Harbor StatementThe following is intended to outline our general product direction. It is intended forinformation purpose only, and may not be incorporated into any contract. It is not acommitment to deliver any material, code, or functionality, and should not be relied up inmaking purchasing decisions. The development, release and timing of any features orfunctionality described for Oracle´s product remains at the sole discretion of Oracle.

Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.

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Who are we ?


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Frédéric Descamps@lefredMySQL EvangelistManaging MySQL since 3.23devops believerhttp://about.me/lefred


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http://about.me/lefred

Kenny Gryp@grypMySQL Practice Manager


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get more at the conference

MySQL Group Replication


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AgendaPrepare your workstation


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AgendaPrepare your workstationWhat are MySQL InnoDB Cluster & Group Replication ?


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AgendaPrepare your workstationWhat are MySQL InnoDB Cluster & Group Replication ?Migration from Master-Slave to GR


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AgendaPrepare your workstationWhat are MySQL InnoDB Cluster & Group Replication ?Migration from Master-Slave to GRHow to monitor ?


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AgendaPrepare your workstationWhat are MySQL InnoDB Cluster & Group Replication ?Migration from Master-Slave to GRHow to monitor ?Application interaction


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VirtualBox

Setup your workstation


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Setup your workstationInstall VirtualBox 5On the USB key, copy PLeu17_GR.ova on your laptop and doubleclick on itEnsure you have vboxnet2 network interface (VirtualBox Preferences -> Network -> Host-Only Networks -> +)Start all virtual machines (mysql1, mysql2, mysql3 & mysql4)Install putty if you are using Windows


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Setup your workstationInstall VirtualBox 5On the USB key, copy PLeu17_GR.ova on your laptop and doubleclick on itEnsure you have vboxnet2 network interface (VirtualBox Preferences -> Network -> Host-Only Networks -> +)Start all virtual machines (mysql1, mysql2, mysql3 & mysql4)Install putty if you are using WindowsTry to connect to all VM´s from your terminal or putty (root password is X) :

ssh -p 8821 [email protected] to mysql1ssh -p 8822 [email protected] to mysql2ssh -p 8823 [email protected] to mysql3ssh -p 8824 [email protected] to mysql4


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LAB1: Current situation


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launchrun_app.sh

on mysql1 intoa screensessionverify thatmysql2 is arunning slave

LAB1: Current situation


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Summary

+--------+----------+--------------+-----------------+| | ROLE | SSH PORT | INTERNAL IP |+--------+----------+--------------+-----------------+ | | | | | | mysql1 | master | 8821 | 192.168.56.11 | | | | | | | mysql2 | slave | 8822 | 192.168.56.12 | | | | | | | mysql3 | n/a | 8823 | 192.168.56.13 | | | | | | | mysql4 | n/a | 8824 | 192.168.56.14 | | | | | | +--------+----------+--------------+-----------------+


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Easy High Availability

MySQL InnoDB Cluster


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InnoDB

cluster

Ease-of-Use

Extreme Scale-Out

Out-of-Box Solution

Built-in HA

High Performance

Everything Integrated


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InnoDB Cluster's Architecture

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Group Replication: heart of MySQL InnoDBCluster


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Group Replication: heart of MySQL InnoDBCluster


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but what is it ?!?


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but what is it ?!?

GR is a plugin for MySQL, made by MySQL and packaged with MySQL


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but what is it ?!?

GR is a plugin for MySQL, made by MySQL and packaged with MySQLGR is an implementation of Replicated Database State Machine theory


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but what is it ?!?

GR is a plugin for MySQL, made by MySQL and packaged with MySQLGR is an implementation of Replicated Database State Machine theoryPaxos based protocol


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but what is it ?!?

GR is a plugin for MySQL, made by MySQL and packaged with MySQLGR is an implementation of Replicated Database State Machine theoryPaxos based protocolGR allows to write on all Group Members (cluster nodes) simultaneously whileretaining consistency


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but what is it ?!?

GR is a plugin for MySQL, made by MySQL and packaged with MySQLGR is an implementation of Replicated Database State Machine theoryPaxos based protocolGR allows to write on all Group Members (cluster nodes) simultaneously whileretaining consistencyGR implements conflict detection and resolution


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but what is it ?!?

GR is a plugin for MySQL, made by MySQL and packaged with MySQLGR is an implementation of Replicated Database State Machine theoryPaxos based protocolGR allows to write on all Group Members (cluster nodes) simultaneously whileretaining consistencyGR implements conflict detection and resolutionGR allows automatic distributed recovery


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but what is it ?!?

GR is a plugin for MySQL, made by MySQL and packaged with MySQLGR is an implementation of Replicated Database State Machine theoryPaxos based protocolGR allows to write on all Group Members (cluster nodes) simultaneously whileretaining consistencyGR implements conflict detection and resolutionGR allows automatic distributed recoverySupported on all MySQL platforms !!

Linux, Windows, Solaris, OSX, FreeBSD


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And for users ?


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And for users ?not longer necessary to handle server fail-over manually or with a complicated script


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And for users ?not longer necessary to handle server fail-over manually or with a complicated scriptGR provides fault tolerance


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And for users ?not longer necessary to handle server fail-over manually or with a complicated scriptGR provides fault toleranceGR enables update-everywhere setups


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And for users ?not longer necessary to handle server fail-over manually or with a complicated scriptGR provides fault toleranceGR enables update-everywhere setupsGR handles crashes, failures, re-connects automatically


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And for users ?not longer necessary to handle server fail-over manually or with a complicated scriptGR provides fault toleranceGR enables update-everywhere setupsGR handles crashes, failures, re-connects automaticallyAllows an easy setup of a highly available MySQL service!


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ready ?

Migration from Master-Slave to GR


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The plan


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1) We install andsetup MySQL InnoDBCluster on one of thenew servers

The plan


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2) We restore abackup

3) setupasynchronousreplication on the newserver.

The plan


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4) We add a newinstance to our group

The plan


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5) We point theapplication to one ofour new nodes.

6) We wait and checkthat asynchronousreplication is caughtup

7) we stop thoseasynchronous slaves

The plan


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8) We attach themysql2 slave to thegroup

The plan


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9) Use MySQL Routerfor directing traffic

The plan


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Latest MySQL 8.0.3-RC is already installedon mysql3.

Let´s take a backup on mysql1:

[mysql1 ~]# xtrabackup --backup \ --target-dir=/tmp/backup \ --user=root \ --password=X --host=127.0.0.1

[mysql1 ~]# xtrabackup --prepare \ --target-dir=/tmp/backup

LAB2: Prepare mysql3Asynchronous slave

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LAB2: Prepare mysql3 (2)Asynchronous slave

Copy the backup from mysql1 to mysql3:

[mysql1 ~]# scp -r /tmp/backup mysql3:/tmp

And restore it:

[mysql3 ~]# systemctl stop mysqld[mysql3 ~]# rm -rf /var/lib/mysql/*[mysql3 ~]# xtrabackup --copy-back --target-dir=/tmp/backup [mysql3 ~]# chown -R mysql. /var/lib/mysql

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LAB3: mysql3 as asynchronous slave (2)Asynchronous slave

Configure /etc/my.cnf with the minimal requirements:

[mysqld]...server_id=3enforce_gtid_consistency = ongtid_mode = on#log_bin # new default #log_slave_updates # new default


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Let´s start MySQL on mysql3:

[mysql3 ~]# systemctl start mysqld


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Let´s start MySQL on mysql3:


[mysql3 ~]# mysql_upgrade


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find the GTIDs purgedchange MASTERset the purged GTIDsstart replication

LAB3: mysql3 as asynchronous slave (1)


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LAB3: mysql3 as asynchronous slave (2)Find the latest purged GTIDs:

[mysql3 ~]# cat /tmp/backup/xtrabackup_binlog_info mysql-bin.000002 167646328 b346474c-8601-11e6-9b39-08002718d305:1-771

Connect to mysql3 and setup replication:

mysql> CHANGE MASTER TO MASTER_HOST="mysql1", MASTER_USER="repl_async", MASTER_PASSWORD='Xslave', MASTER_AUTO_POSITION=1;

mysql> RESET MASTER;mysql> SET global gtid_purged="VALUE FOUND PREVIOUSLY";

mysql> START SLAVE;

Check that you receive the application´s traffic

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Administration made easy and more...

MySQL-Shell


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MySQL ShellThe MySQL Shell is an interactive Javascript, Python, or SQL interface supportingdevelopment and administration for MySQL. MySQL Shell includes the AdminAPI--availablein JavaScript and Python--which enables you to set up and manage InnoDB clusters. Itprovides a modern and fluent API which hides the complexity associated with configuring,provisioning, and managing an InnoDB cluster, without sacrificing power, flexibility, orsecurity.


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MySQL Shell (2)As example. the same operations as before but using the Shell:


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MySQL Shell (3)


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LAB4: MySQL InnoDB ClusterCreate a single instance cluster

Time to use the new MySQL Shell !

[mysql3 ~]# mysqlsh

Let´s verify if our server is ready to become a member of a new cluster:

mysql-js> dba.checkInstanceCon�guration('root@mysql3:3306')


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LAB4: MySQL InnoDB ClusterCreate a single instance cluster

Time to use the new MySQL Shell !

[mysql3 ~]# mysqlsh

Let´s verify if our server is ready to become a member of a new cluster:


Change the configuration !

mysql-js> dba.con�gureLocalInstance()


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LAB4: MySQL InnoDB Cluster (2)Restart mysqld to use the new configuration:

[mysql3 ~]# systemctl restart mysqld


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Create a single instance cluster

[mysql3 ~]# mysqlsh


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Create a single instance cluster

[mysql3 ~]# mysqlsh


mysql-js> \c root@mysql3:3306

mysql-js> cluster = dba.createCluster('perconalive')


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LAB4: Cluster Statusmysql-js> cluster.status(){ "clusterName": "perconalive", "defaultReplicaSet": { "name": "default", "primary": "mysql3:3306", "ssl": "DISABLED", "status": "OK_NO_TOLERANCE", "statusText": "Cluster is NOT tolerant to any failures.", "topology": { "mysql3:3306": { "address": "mysql3:3306", "mode": "R/W", "readReplicas": {}, "role": "HA", "status": "ONLINE" } } }}


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Add mysql4 to the Group:

restore the backupset the purged GTIDsuse MySQL Shell

LAB5: add mysql4 to the cluster (1)


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[mysql4 ~]# mysql_upgrade

LAB5: add mysql4 to the cluster (2)Copy the backup from mysql1 to mysql4:

[mysql1 ~]# scp -r /tmp/backup mysql4:/tmp

And restore it:

[mysql4 ~] systemctl stop mysqld[mysql4 ~] rm -rf /var/lib/mysql/*[mysql4 ~]# xtrabackup --copy-back --target-dir=/tmp/backup [mysql4 ~]# chown -R mysql. /var/lib/mysql

Start MySQL on mysql4:

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LAB5: MySQL Shell to add an instance (3)[mysql4 ~]# mysqlsh

Let´s verify the config:



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And change the configuration:



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And change the configuration:


Restart the service to enable the changes:



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LAB5: MySQL InnoDB Cluster (4)Group of 2 instances

Find the latest purged GTIDs:

[mysql4 ~]# cat /tmp/backup/xtrabackup_binlog_info mysql-bin.000002 167646328 b346474c-8601-11e6-9b39-08002718d305:1-77177

Connect to mysql4 and set GTID_PURGED

[mysql4 ~]# mysqlsh

mysql-js> \c root@mysql4:3306mysql-js> \sqlmysql-sql> RESET MASTER;mysql-sql> SET global gtid_purged="VALUE FOUND PREVIOUSLY";


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LAB5: MySQL InnoDB Cluster (5)mysql-sql> \js



mysql-js> cluster = dba.getCluster()

mysql-js> cluster.checkInstanceState('root@mysql4:3306')

mysql-js> cluster.addInstance("root@mysql4:3306")

mysql-js> cluster.status()


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Cluster Statusmysql-js> cluster.status(){ "clusterName": "perconalive", "defaultReplicaSet": { "name": "default", "primary": "mysql3:3306", "ssl": "DISABLED", "status": "OK_NO_TOLERANCE", "statusText": "Cluster is NOT tolerant to any failures. 1 member is not active" "topology": { "mysql3:3306": { "address": "mysql3:3306", "mode": "R/W", "readReplicas": {}, "role": "HA", "status": "ONLINE" }, "mysql4:3306": { "address": "mysql4:3306", "mode": "R/O", "readReplicas": {}, "role": "HA", "status": "RECOVERING" } } } Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.

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Recovering progressOn standard MySQL, monitor the group_replication_recovery channel to seethe progress:

mysql4> show slave status for channel 'group_replication_recovery'\G *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: mysql3 Master_User: mysql_innodb_cluster_rpl_user ... Slave_IO_Running: Yes Slave_SQL_Running: Yes ... Retrieved_Gtid_Set: 6e7d7848-860f-11e6-92e4-08002718d305:1-6,7c1f0c2d-860d-11e6-9df7-08002718d305:1-15,b346474c-8601-11e6-9b39-08002718d305:1964-77177,e8c524df-860d-11e6-9df7-08002718d305:1-2 Executed_Gtid_Set: 7c1f0c2d-860d-11e6-9df7-08002718d305:1-7,b346474c-8601-11e6-9b39-08002718d305:1-45408,e8c524df-860d-11e6-9df7-08002718d305:1-2 ...


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point the applicationto the cluster

Migrate the application


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LAB6: Migrate the applicationMake sure gtid_executed range on mysql2 is lower or equal than on mysql3

mysql[2-3]> show global variables like 'gtid_executed'\G


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LAB6: Migrate the applicationMake sure gtid_executed range on mysql2 is lower or equal than on mysql3

mysql[2-3]> show global variables like 'gtid_executed'\G

When they are OK, stop asynchronous replication on mysql2 and mysql3:

mysql2> stop slave;mysql3> stop slave;


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LAB6: Migrate the applicationNow we need to point the application to mysql3, this is the only downtime !

...[ 21257s] threads: 4, tps: 12.00, reads: 167.94, writes: 47.98, response time: 18[ 21258s] threads: 4, tps: 6.00, reads: 83.96, writes: 23.99, response time: 14[ 21259s] threads: 4, tps: 7.00, reads: 98.05, writes: 28.01, response time: 16[ 31250s] threads: 4, tps: 8.00, reads: 111.95, writes: 31.99, response time: 30[ 31251s] threads: 4, tps: 11.00, reads: 154.01, writes: 44.00, response time: 13[ 31252s] threads: 4, tps: 11.00, reads: 153.94, writes: 43.98, response time: 12[ 31253s] threads: 4, tps: 10.01, reads: 140.07, writes: 40.02, response time: 17^C[mysql1 ~]# run_app.sh mysql3


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LAB6: Migrate the applicationNow we need to point the application to mysql3, this is the only downtime !

...[ 21257s] threads: 4, tps: 12.00, reads: 167.94, writes: 47.98, response time: 18[ 21258s] threads: 4, tps: 6.00, reads: 83.96, writes: 23.99, response time: 14[ 21259s] threads: 4, tps: 7.00, reads: 98.05, writes: 28.01, response time: 16[ 31250s] threads: 4, tps: 8.00, reads: 111.95, writes: 31.99, response time: 30[ 31251s] threads: 4, tps: 11.00, reads: 154.01, writes: 44.00, response time: 13[ 31252s] threads: 4, tps: 11.00, reads: 153.94, writes: 43.98, response time: 12[ 31253s] threads: 4, tps: 10.01, reads: 140.07, writes: 40.02, response time: 17^C[mysql1 ~]# run_app.sh mysql3

Now they can forget about mysql1:

mysql[2-3]> reset slave all;


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previous slave(mysql2) can nowbe part of the cluster

Add a third instance


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LAB7: Add mysql2 to the groupWe first upgrade to MySQL 8.0.3 :


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[mysql2 ~]# systemctl stop mysqld[mysql2 ~]# rpm -Uvh /root/rpms/mysql*rpm[mysql2 ~]# systemctl start mysqld[mysql2 ~]# mysql_upgrade


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and then we validate the instance using MySQL Shell and we configure it:

[mysql2 ~]# mysqlsh


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[mysql2 ~]# mysqlsh




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[mysql2 ~]# mysqlsh





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LAB7: Add mysql2 to the group (2)Back in MySQL Shell we add the new instance:

[mysql2 ~]# mysqlsh


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LAB7: Add mysql2 to the group (2)Back in MySQL Shell we add the new instance:

[mysql2 ~]# mysqlsh




mysql-js> cluster.addInstance("root@mysql2:3306")



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LAB7: Add mysql2 to the group (3){ "clusterName": "perconalive", "defaultReplicaSet": { "name": "default", "primary": "mysql3:3306", "status": "OK", "statusText": "Cluster is ONLINE and can tolerate up to ONE failure.", "topology": { "mysql2:3306": { "address": "mysql2:3306", "mode": "R/O", "readReplicas": {}, "role": "HA", "status": "ONLINE" }, "mysql3:3306": { "address": "mysql3:3306", "mode": "R/W", "readReplicas": {}, "role": "HA", "status": "ONLINE" }, "mysql4:3306": { "address": "mysql4:3306", "mode": "R/O", "readReplicas": {}, Copyright @ 2017 Oracle and/or its affiliates. All rights reserved.

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writing to a single server

Single Primary Mode


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Default = Single Primary ModeBy default, MySQL InnoDB Cluster enables Single Primary Mode.


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mysql> show global variables like 'group_replication_single_primary_mode';+---------------------------------------+-------+| Variable_name | Value |+---------------------------------------+-------+| group_replication_single_primary_mode | ON |+---------------------------------------+-------+


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mysql> show global variables like 'group_replication_single_primary_mode';+---------------------------------------+-------+| Variable_name | Value |+---------------------------------------+-------+| group_replication_single_primary_mode | ON |+---------------------------------------+-------+

In Single Primary Mode, a single member acts as the writable master (PRIMARY) and therest of the members act as hot-standbys (SECONDARY).

The group itself coordinates and configures itself automatically to determine whichmember will act as the PRIMARY, through a leader election mechanism.


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Who´s the Primary Master ? old fashion styleAs the Primary Master is elected, all nodes part of the group knows which one waselected. This value is exposed in status variables:


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mysql> show status like 'group_replication_primary_member';+----------------------------------+--------------------------------------+| Variable_name | Value |+----------------------------------+--------------------------------------+| group_replication_primary_member | 28a4e51f-860e-11e6-bdc4-08002718d305 |+----------------------------------+--------------------------------------+


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mysql> show status like 'group_replication_primary_member';+----------------------------------+--------------------------------------+| Variable_name | Value |+----------------------------------+--------------------------------------+| group_replication_primary_member | 28a4e51f-860e-11e6-bdc4-08002718d305 |+----------------------------------+--------------------------------------+

mysql> select member_host as "primary master" from performance_schema.global_status join performance_schema.replication_group_members where variable_name = 'group_replication_primary_member' and member_id=variable_value;+---------------+| primary master|+---------------+| mysql3 |+---------------+


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Who´s the Primary Master ? new fashion stylemysql> select member_host from performance_schema.replication_group_members where member_role='PRIMARY';+-------------+| member_host |+-------------+| mysql3 |+-------------+


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Create a Multi-Primary Cluster:It´s also possible to create a Multi-Primary Cluster using the Shell:


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mysql-js> cluster=dba.createCluster('perconalive',{multiMaster: true})


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A new InnoDB cluster will be created on instance 'root@mysql3:3306'.

The MySQL InnoDB cluster is going to be setup in advanced Multi-Master Mode.Before continuing you have to con�rm that you understand the requirements andlimitations of Multi-Master Mode. Please read the manual before proceeding.

I have read the MySQL InnoDB cluster manual and I understand the requirementsand limitations of advanced Multi-Master Mode.Con�rm [y|N]:


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Or you can force it to avoid interaction (for automation) :


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Or you can force it to avoid interaction (for automation) :

> cluster=dba.createCluster('perconalive',{multiMaster: true, force: true})


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get more info

Monitoring


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Performance SchemaGroup Replication uses Performance_Schema to expose status

mysql3> SELECT * FROM performance_schema.replication_group_members\G *************************** 1. row *************************** CHANNEL_NAME: group_replication_applier MEMBER_ID: ade14d5c-9e1e-11e7-b034-08002718d305 MEMBER_HOST: mysql4 MEMBER_PORT: 3306 MEMBER_STATE: ONLINE MEMBER_ROLE: SECONDARYMEMBER_VERSION: 8.0.3 *************************** 2. row *************************** CHANNEL_NAME: group_replication_applier MEMBER_ID: b9d01593-9dfb-11e7-8ca6-08002718d305 MEMBER_HOST: mysql3 MEMBER_PORT: 3306 MEMBER_STATE: ONLINE MEMBER_ROLE: PRIMARYMEMBER_VERSION: 8.0.3


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mysql3> SELECT * FROM performance_schema.replication_connection_status\G *************************** 1. row *************************** CHANNEL_NAME: group_replication_applier GROUP_NAME: 8fc848d7-9e1c-11e7-9407... SOURCE_UUID: 8fc848d7-9e1c-11e7-9407... THREAD_ID: NULL SERVICE_STATE: ON COUNT_RECEIVED_HEARTBEATS: 0 LAST_HEARTBEAT_TIMESTAMP: 0000-00-00 00:00:00 RECEIVED_TRANSACTION_SET: 8fc848d7-9e1c-11e7-9407...b9d01593-9dfb-11e7-8ca6-08002718d305:1-21,da2f0910-8767-11e6-b82d-08002718d305:1-164741 LAST_ERROR_NUMBER: 0 LAST_ERROR_MESSAGE: LAST_ERROR_TIMESTAMP: 0000-00-00 00:00:00 LAST_QUEUED_TRANSACTION: 8fc848d7-9e1c-11e7-9407... LAST_QUEUED_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00LAST_QUEUED_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00 LAST_QUEUED_TRANSACTION_START_QUEUE_TIMESTAMP: 2017-09-20 16:22:36.486... LAST_QUEUED_TRANSACTION_END_QUEUE_TIMESTAMP: 2017-09-20 16:22:36.486... QUEUEING_TRANSACTION: QUEUEING_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00 QUEUEING_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00 QUEUEING_TRANSACTION_START_QUEUE_TIMESTAMP: 0000-00-00 00:00:00


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Member StateThese are the different possible state for a node member:

ONLINE

OFFLINE

RECOVERING

ERROR: when a node is leaving but the plugin was not instructed to stopUNREACHABLE


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Status information & metrics

Membersmysql> SELECT member_host, member_state, member_role FROM performance_schema.replication_group_members;


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Membersmysql> SELECT member_host, member_state, member_role FROM performance_schema.replication_group_members;

+-------------+--------------+-------------+| member_host | member_state | member_role |+-------------+--------------+-------------+| mysql4 | ONLINE | SECONDARY || mysql3 | ONLINE | PRIMARY |+-------------+--------------+-------------+2 rows in set (0.00 sec)


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Status information & metrics - connectionsmysql> SELECT * FROM performance_schema.replication_connection_status\G


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Status information & metrics - connectionsmysql> SELECT * FROM performance_schema.replication_connection_status\G

*************************** 1. row *************************** CHANNEL_NAME: group_replication_applier GROUP_NAME: 8fc848d7-9e1c-11e7-9407-... SOURCE_UUID: 8fc848d7-9e1c-11e7-9407-... THREAD_ID: NULL SERVICE_STATE: ON COUNT_RECEIVED_HEARTBEATS: 0 LAST_HEARTBEAT_TIMESTAMP: 0000-00-00 00:00:00 RECEIVED_TRANSACTION_SET: 8fc848d7-9e1c-11e7-9407-...b9d01593-9dfb-11e7-8ca6-08002718d305:1-21,da2f0910-8767-11e6-b82d-08002718d305:1-164741 LAST_ERROR_NUMBER: 0 LAST_ERROR_MESSAGE: LAST_ERROR_TIMESTAMP: 0000-00-00 00:00:00 LAST_QUEUED_TRANSACTION: 8fc848d7-9e1c-11e7-9407-... LAST_QUEUED_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00LAST_QUEUED_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00 LAST_QUEUED_TRANSACTION_START_QUEUE_TIMESTAMP: 2017-09-20 16:22:36.4864... LAST_QUEUED_TRANSACTION_END_QUEUE_TIMESTAMP: 2017-09-20 16:22:36.4865... QUEUEING_TRANSACTION: QUEUEING_TRANSACTION_ORIGINAL_COMMIT_TIMESTAMP: 0000-00-00 00:00:00 QUEUEING_TRANSACTION_IMMEDIATE_COMMIT_TIMESTAMP: 0000-00-00 00:00:00 QUEUEING_TRANSACTION_START_QUEUE_TIMESTAMP: 0000-00-00 00:00:00


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Previously there was only local node statistics, now they are exposed allover the Group mysql> select * from performance_schema.replication_group_member_stats\G


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Previously there was only local node statistics, now they are exposed allover the Group mysql> select * from performance_schema.replication_group_member_stats\G

************************** 1. row *************************** CHANNEL_NAME: group_replication_applier VIEW_ID: 15059231192196925:2 MEMBER_ID: ade14d5c-9e1e-11e7-b034-08002... COUNT_TRANSACTIONS_IN_QUEUE: 0 COUNT_TRANSACTIONS_CHECKED: 27992 COUNT_CONFLICTS_DETECTED: 0 COUNT_TRANSACTIONS_ROWS_VALIDATING: 0 TRANSACTIONS_COMMITTED_ALL_MEMBERS: 8fc848d7-9e1c-11e7-9407-08002...b9d01593-9dfb-11e7-8ca6-08002718d305:1-21,da2f0910-8767-11e6-b82d-08002718d305:1-164741 LAST_CONFLICT_FREE_TRANSACTION: 8fc848d7-9e1c-11e7-9407-08002...COUNT_TRANSACTIONS_REMOTE_IN_APPLIER_QUEUE: 0 COUNT_TRANSACTIONS_REMOTE_APPLIED: 27992 COUNT_TRANSACTIONS_LOCAL_PROPOSED: 0 COUNT_TRANSACTIONS_LOCAL_ROLLBACK: 0


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************************** 2. row *************************** CHANNEL_NAME: group_replication_applier VIEW_ID: 15059231192196925:2 MEMBER_ID: b9d01593-9dfb-11e7-8ca6-08002... COUNT_TRANSACTIONS_IN_QUEUE: 0 COUNT_TRANSACTIONS_CHECKED: 28000 COUNT_CONFLICTS_DETECTED: 0 COUNT_TRANSACTIONS_ROWS_VALIDATING: 0 TRANSACTIONS_COMMITTED_ALL_MEMBERS: 8fc848d7-9e1c-11e7-9407-08002...b9d01593-9dfb-11e7-8ca6-08002718d305:1-21,da2f0910-8767-11e6-b82d-08002718d305:1-164741 LAST_CONFLICT_FREE_TRANSACTION: 8fc848d7-9e1c-11e7-9407-08002...COUNT_TRANSACTIONS_REMOTE_IN_APPLIER_QUEUE: 0 COUNT_TRANSACTIONS_REMOTE_APPLIED: 1 COUNT_TRANSACTIONS_LOCAL_PROPOSED: 28000 COUNT_TRANSACTIONS_LOCAL_ROLLBACK: 0


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Performance_SchemaYou can find GR information in the following Performance_Schema tables:

replication_applier_con�guration

replication_applier_status

replication_applier_status_by_worker

replication_connection_con�guration

replication_connection_status

replication_group_member_stats

replication_group_members


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Status during recovery mysql> SHOW SLAVE STATUS FOR CHANNEL 'group_replication_recovery'\G


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Status during recovery mysql> SHOW SLAVE STATUS FOR CHANNEL 'group_replication_recovery'\G

*************************** 1. row *************************** Slave_IO_State: Master_Host: <NULL> Master_User: gr_repl Master_Port: 0 ... Relay_Log_File: mysql4-relay-bin-group_replication_recovery.000001 ... Slave_IO_Running: No Slave_SQL_Running: No ... Executed_Gtid_Set: 5de4400b-3dd7-11e6-8a71-08002774c31b:1-814089, afb80f36-2bff-11e6-84e0-0800277dd3bf:1-5718 ... Channel_Name: group_replication_recovery


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Sys SchemaThe easiest way to detect if a node is a member of the primary component (when thereare partitioning of your nodes due to network issues for example) and therefore a validcandidate for routing queries to it, is to use the sys table.

Additional information for sys can be found at https://goo.gl/XFp3bt

On the primary node:

[mysql3 ~]# mysql < /root/addition_to_sys_mysql8.sql


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https://goo.gl/XFp3bt

Sys SchemaIs this node part of PRIMARY Partition:

mysql3> SELECT sys.gr_member_in_primary_partition();+------------------------------------+| sys.gr_node_in_primary_partition() |+------------------------------------+| YES |+------------------------------------+


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Sys SchemaIs this node part of PRIMARY Partition:

mysql3> SELECT sys.gr_member_in_primary_partition();+------------------------------------+| sys.gr_node_in_primary_partition() |+------------------------------------+| YES |+------------------------------------+

To use as healthcheck:

mysql3> SELECT * FROM sys.gr_member_routing_candidate_status;+------------------+-----------+---------------------+----------------------+| viable_candidate | read_only | transactions_behind | transactions_to_cert |+------------------+-----------+---------------------+----------------------+| YES | YES | 0 | 0 |+------------------+-----------+---------------------+----------------------+


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LAB8: Sys Schema - Health CheckOn one of the non Primary nodes, run the following command:

mysql-sql> �ush tables with read lock;


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Now you can verify what the healthcheck exposes to you:

mysql-sql> SELECT * FROM sys.gr_member_routing_candidate_status;+------------------+-----------+---------------------+----------------------+| viable_candidate | read_only | transactions_behind | transactions_to_cert |+------------------+-----------+---------------------+----------------------+| YES | YES | 950 | 0 |+------------------+-----------+---------------------+----------------------+


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Now you can verify what the healthcheck exposes to you:

mysql-sql> SELECT * FROM sys.gr_member_routing_candidate_status;+------------------+-----------+---------------------+----------------------+| viable_candidate | read_only | transactions_behind | transactions_to_cert |+------------------+-----------+---------------------+----------------------+| YES | YES | 950 | 0 |+------------------+-----------+---------------------+----------------------+

mysql-sql> UNLOCK TABLES;


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application interaction

MySQL Router


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MySQL RouterMySQL Router is lightweight middleware that provides transparent routing between yourapplication and backend MySQL Servers. It can be used for a wide variety of use cases,such as providing high availability and scalability by effectively routing database traffic toappropriate backend MySQL Servers.


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MySQL RouterMySQL Router is lightweight middleware that provides transparent routing between yourapplication and backend MySQL Servers. It can be used for a wide variety of use cases,such as providing high availability and scalability by effectively routing database traffic toappropriate backend MySQL Servers.

MySQL Router doesn´t require any specific configuration. It configures itself automatically(bootstrap) using MySQL InnoDB Cluster´s metadata.


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LAB9: MySQL RouterWe will now use mysqlrouter between our application and the cluster.


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LAB9: MySQL Router (2)Configure MySQL Router that will run on the app server (mysql1). We bootstrap it usingthe Primary-Master:

[root@mysql1 ~]# mysqlrouter --bootstrap mysql3:3306 --user mysqlrouterPlease enter MySQL password for root: WARNING: The MySQL server does not have SSL ...

Bootstrapping system MySQL Router instance...MySQL Router has now been con�gured for the InnoDB cluster 'perconalive'.

The following connection information can be used to connect to the cluster.

Classic MySQL protocol connections to cluster 'perconalive':- Read/Write Connections: localhost:6446- Read/Only Connections: localhost:6447

X protocol connections to cluster 'perconalive':- Read/Write Connections: localhost:64460- Read/Only Connections: localhost:64470

[root@mysql1 ~]# chown -R mysqlrouter. /var/lib/mysqlrouter


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LAB9: MySQL Router (3)Now let´s modify the configuration file to listen on port 3306:


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in /etc/mysqlrouter/mysqlrouter.conf:

[routing:perconalive_default_rw]-bind_port=6446+bind_port=3306


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in /etc/mysqlrouter/mysqlrouter.conf:

[routing:perconalive_default_rw]-bind_port=6446+bind_port=3306

We can stop mysqld on mysql1 and start mysqlrouter into a screen session:

[mysql1 ~]# systemctl stop mysqld[mysql1 ~]# systemctl start mysqlrouter


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LAB9: MySQL Router (4)Before killing a member we will change systemd´s default behavior that restartsmysqld immediately:


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LAB9: MySQL Router (4)Before killing a member we will change systemd´s default behavior that restartsmysqld immediately:

in /usr/lib/systemd/system/mysqld.service add the following under[Service]

RestartSec=30

[mysql3 ~]# systemctl daemon-reload


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LAB9: MySQL Router (5)Now we can point the application to the router (back to mysql1):

[mysql1 ~]# run_app.sh


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Check app and kill mysqld on mysql3 (the Primary Master R/W node) !

[mysql3 ~]# kill -9 $(pidof mysqld)


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Check app and kill mysqld on mysql3 (the Primary Master R/W node) !


mysql2> select member_host from performance_schema.replication_group_members where member_role='PRIMARY';+-------------+| member_host |+-------------+| mysql4 |+-------------+


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ProxySQL / HA Proxy / F5 / ...

3rd party router/proxy


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3rd party router/proxyMySQL InnoDB Cluster can also work with third party router / proxy.


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If you need some specific features that are not yet available in MySQL Router, liketransparent R/W splitting, then you can use your software of choice.


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The important part of such implementation is to use a good health check to verify if theMySQL server you plan to route the traffic is in a valid state.


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MySQL Router implements that natively, and it´s very easy to deploy.


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ProxySQL also has native support for GroupReplication which makes it maybe the bestchoice for advanced users.




MySQL Router implements that natively, and it´s very easy to deploy.


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operational tasks

Recovering Node


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Recovering Nodes/MembersThe old master (mysql3) got killed.


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MySQL got restarted automatically by systemd


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MySQL got restarted automatically by systemd

Let´s add mysql3 back to the cluster


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LAB10: Recovering Nodes/Members[mysql3 ~]# mysqlsh

mysql-js> \c root@mysql4:3306 # The current master



mysql-js> cluster.rejoinInstance("root@mysql3:3306")

Rejoining the instance to the InnoDB cluster. Depending on the originalproblem that made the instance unavailable, the rejoin operation might not besuccessful and further manual steps will be needed to �x the underlyingproblem.

Please monitor the output of the rejoin operation and take necessary action ifthe instance cannot rejoin.

Please provide the password for 'root@mysql3:3306': Rejoining instance to the cluster ...

The instance 'root@mysql3:3306' was successfully rejoined on the cluster.

The instance 'mysql3:3306' was successfully added to the MySQL Cluster.


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mysql-js> cluster.status(){ "clusterName": "perconalive", "defaultReplicaSet": { "name": "default", "primary": "mysql4:3306", "status": "OK", "statusText": "Cluster is ONLINE and can tolerate up to ONE failure.", "topology": { "mysql2:3306": { "address": "mysql2:3306", "mode": "R/O", "readReplicas": {}, "role": "HA", "status": "ONLINE" }, "mysql3:3306": { "address": "mysql3:3306", "mode": "R/O", "readReplicas": {}, "role": "HA", "status": "ONLINE" }, "mysql4:3306": { "address": "mysql4:3306", "mode": "R/W", "readReplicas": {}, "role": "HA", "status": "ONLINE" } } }}


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Recovering Nodes/Members (automatically)This time before killing a member of the group, we will persist the configuration on disk inmy.cnf.


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Recovering Nodes/Members (automatically)This time before killing a member of the group, we will persist the configuration on disk inmy.cnf.

We will use again the same MySQL command as previouslydba.con�gureLocalInstance() but this time when all nodes are already partof the Group.


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LAB10: Recovering Nodes/Members (2)Verify that all nodes are ONLINE.

...mysql-js> cluster.status()


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LAB10: Recovering Nodes/Members (2)Verify that all nodes are ONLINE.

...mysql-js> cluster.status()

Then on all nodes run:



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LAB10: Recovering Nodes/Members (3)Kill one node again:


systemd will restart mysqld and verify if the node joined.


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Thank you !

Any Questions ?


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