The document discusses the integration of MySQL as a default database component within OpenStack, highlighting its widespread usage in large web properties and as a persistent data store for OpenStack components. It explains the functionality of Galera Cluster and MySQL Group Replication for achieving high availability and distributed databases, detailing their features and use cases. Additionally, it compares MySQL Group Replication and MySQL NDB Cluster in terms of architecture, consistency models, and operational complexities.

1. MySQL Options in OpenStack
Matt Lord
MySQL Product Manager
August 23, 2016

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3. MySQL in OpenStack
Default database component

4. How Is It Used?
• MySQL is the world’s most popular FOSS database
• The worlds biggest web properties rely on it
• Facebook, Twitter, LinkedIn, Booking.com, Taobao, …
• As well as many of the worlds largest banks and governments
• OpenStack components use MySQL as a persistent data store
• Standard MySQL installation, using InnoDB and UTF8
• Standard operations – install, configure, backup, etc.
• For HA or Active/Active setups, MySQL+Galera is the de facto standard
• At the heart of the RedDwarf project, which became Trove
• MySQL is still the most widely used/supported database in Trove today
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5. Galera
3rd party active/active update anywhere clusters

6. What Is It?
• Write Set Replication library
• Officially called “Galera Cluster for MySQL”
• Implementation of Replicated Database State Machine theory
• More specifically it uses a Totem based GCS
• Provides virtually synchronous replication for MySQL/InnoDB 5.1+
• Bundled in MariaDB 10 and Percona XtraDB Cluster 5.5+
• Fully supported on Linux only
• Created by Codership Oy
• Founded in 2007
• 1.0 GA release in Oct 2011
• 2.0 released Feb 2012
• 3.0 released Sept 2013 (latest major release)
6

7. MySQL
Group Replication
Native active/active update anywhere clusters

8. What Is It?
“Multi-master update anywhere replication plugin for MySQL with
built-in conflict detection and resolution, automatic distributed
recovery, and group membership.”
• Group Replication library
• Implementation of Replicated Database State Machine theory
• MySQL GCS is based on Paxos (variant of Mencius)
• Provides virtually synchronous replication for MySQL/InnoDB 5.7+
• Supported on all MySQL platforms
• Linux, Windows, Solaris, OSX, FreeBSD
• Latest release is 0.8, with “1.0” approaching fast
8

9. What Does It Provide?
• A highly available distributed MySQL database service
• Removes the need for manually handling server fail-over
• Provides distributed fault tolerance
• Enables Active/Active update anywhere setups
• Automates reconfiguration (adding/removing nodes, crashes, failures)
• Automatically detects and handles conflicts
9

10. Use Cases
• Elastic Replication
• Environments that require a very fluid replication infrastructure, where
the number of servers has to grow or shrink dynamically and with as
little pain as possible.
• Highly Available Shards
• Sharding is a popular approach to achieve write scale-out. Users can
use MySQL Group Replication to implement highly available shards in
a federated system. Each shard can map into a Replication Group.
• Alternative to Master-Slave replication
• It may be that a single master server makes it a single point of
contention. Writing to an entire group may prove more scalable under
certain circumstances.
10

11. What Does It Look Like?
11
Node Types
R: Traffic routers/proxies: mysqlrouter, haproxy, sqlproxy, ...
M: mysqld nodes participating in Group Replication

12. The Internal Stack
12

13. Major Building Blocks: MySQL Server
• Server calls into the plugin through a
generic interface
• Most server internals are hidden from the plugin
• Plugin interacts with the server through a
generic interface
• Replication plugin determines the fate of the
commit operation through a well defined server
interface
• The plugin makes use of the relay log
infrastructure to inject changes in the receiving
server
13
GCS API
Replication
Plugin
Plugin API
MySQL
Server
Group Comm.
System (Corosync)
Group Com. Engine

14. Major Building Blocks: Replication Plugin
• The plugin is responsible for
• Maintaining distributed execution context
• Detecting and handling conflicts
• Handling distributed recovery
• Detect membership changes
• Donate state if needed
• Collect state if needed
• Proposing transactions to other members
• Receiving and handling transactions from other
members
• Deciding the ultimate fate of transactions
• commit or rollback
14
GCS API
Replication
Plugin
Plugin API
MySQL
Server
Group Comm.
System (Corosync)
Group Com. Engine

15. Major Building Blocks: MySQL GCS
• The communication API (and binding) is
responsible for:
• Abstracting the underlying group communication
system implementation from the plugin itself
• Mapping the interface to a specific group
communication system implementation
• The Group Communication System engine:
• Variant of Paxos developed at MySQL
• Building block to provide distributed agreement
between servers
15
GCS API
Replication
Plugin
Plugin API
MySQL
Server
Group Comm.
System (Corosync)
Group Com. Engine

16. Why Use It Instead of Galera?
• A single provider of software and support
• Important if you require an Enterprise support contract
• Better performance with > 3 nodes
• MySQL GCS is peer to peer, while Galera uses a ring protocol
• Easier monitoring
• Performance Schema tables for group and node status/stats
• Native MySQL HA being built around it
• Native end-to-end easy to use sharded InnoDB clusters
• Stay tuned!
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17. 17
The Bigger Picture…
M
App
M M
Orchestrate & Manage
MApp
M M
Simple Shard
Mapping, State and
Extra Metadata
Control, Coordinate,
Provision
...
Monitoring (MEM)
MySQL Router Group Replication – Shard 1
Group Replication – Shard N
C, Java, JavaScript, Python, ...
MySQL Router

18. MySQL NDB Cluster
For real-time in-memory OLTP and linear R/W scaling

19. What Is It?
“Distributed in-memory database with automatic transparent sharding –
for painless read-write scaling – with SQL and NoSQL APIs, and with
support for Active/Active multi-datacenter geographic clusters.”
• A strongly consistent partitioned/sharded database cluster
• 2PC protocol used for writes
• High performance cross-shard operations
• Transparent shard rebalancing
• Redundancy at every level with millisecond failover
• SQL access via MySQL servers
• NoSQL access with C++, Node.JS, Java, …
• Latest release is 7.5 (now in Release Candidate stage)
• Supported on Linux, Windows, Solaris, OSX
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20. What Does It Provide?
• A highly available distributed MySQL database service
• Transparent sharding
• Support for all cross-shard operations
• Online shard rebalancing
• Automatic and custom sharding schemes
• Strong consistency across all shards
• Transparent built-in load balancing
• Multi-datacenter Active/Active geographic replication
• SQL access via standard MySQL Servers
• Using the NDBCLUSTER storage engine
• Online operations (ALTER TABLE, etc.)
• Direct NoSQL access to the underlying Key/Value storage
• NDB C++ API -- with wrappers for JavaScript, Java, memcached, HTTP/REST
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21. SQL
• Industry standard
• Joins & complex queries
• Relational model
Memcached
• Simple to use API
• Key/value based
• Drivers for many languages
Mod-ndb
• RESTful
• JSON over HTTP
• Plugin for Apache
ClusterJ
• Simple to use Java API
• Web & Telco
• Object Relational Mapping
• Native & fast access to data
ClusterJPA
• OpenJPA plugin
• Standards defined ORM
• Cross table Joins
JavaScript/Node.js
• Native JavaScript: client to
DB
• Blazing fast asynchronous
throughput
SQL and NoSQL APIs
21

22. 22
What Does It Look Like?
Node Types
M: MySQL Server (SQL API)
A: NDB API Node
S: NDB Management Server
D: NDB Data Node

23. 23
• Partition customers across
multiple clusters, distributed by
region to optimize low latency
access
• Each sub-cluster is replicated
for High Availability and DR
• Active/Passive or Active/Active
Geographic Replication for Low-Latency
Local Access
Cluster 2C
Cluster 2B
Cluster 1B
Cluster 1CCluster 2
Cluster 1
Cluster 4
Cluster 3
Cluster 3B
Cluster 3C
Cluster 4C
Cluster 4B

24. 24
How Do The Two Compare?
MySQL Group Replication MySQL NDB Cluster
Storage Engine InnoDB NDBCLUSTER
Distributed Architecture Shared nothing Shared nothing
Consistency Model Weak Consistency Strong Consistency
Sharding No Yes
Arbitration No Yes
Load Balancing No Yes
NoSQL APIs MySQL Document Store Native NDB API
Operational Complexity Medium High
Administration Standard (MySQL) Custom (MySQL + NDB)

25. 25
Case Study: Oracle OpenStack
• MySQL NDB Cluster Active/Active
MySQL Cluster
RabbitMQ
Keepalived
Nova
Neutron
Memcached
Cinder
Swift
Keystone
Glance
Heat
Horizon
Docker
Containers
Controller Node(s)
MySQL Cluster
RabbitMQ
Keepalived
Nova
Neutron
Memcached
Cinder
Swift
Keystone
Glance
Heat
Horizon
Docker
Containers
Container life cycle management (Ansible)
Management Controller Nodes
API
MySQL Cluster Data Nodes
Management
Data Layer
HAProxy
Galera MySQL
Cluster
Scaling Read Linear
Read/Write
Performance Standard Real-time
Online DDL No Yes
Auto Sharding No Yes
NoSQL APIs No Yes
Load Balancing No Yes

26. More Information
• Quick Start Guide: http://mysqlhighavailability.com/mysql-group-
replication-a-quick-start-guide/
• MySQL HA Blog: http://mysqlhighavailability.com
• MySQL Documentation: http://dev.mysql.com/doc/
• Forums
• MySQL Group Replication: http://forums.mysql.com/list.php?26
• MySQL NDB Cluster: http://forums.mysql.com/list.php?25
• Existing customers: http://support.oracle.com
• Sales questions: https://www.mysql.com/buy-mysql/
• Reach out to me directly: @mattalord
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27. 27
THANK YOU!