MySQL InnoDB Cluster: High Availability Made Easy!

Copyright © 2015, Oracle and/or its affiliates. All rights reserved. |
MySQL InnoDB Cluster:
High Availability
Made Easy!
Vittorio Cioe
MySQL Sr. Sales Consultant
vittorio.cioe@oracle.com

Program Agenda
2
An Introduction to InnoDB Clusters
The Components
Setup, Monitoring, and Management
What’s Next?
1
2
3
4

Introduction

…tons of data...
...constantly changing
scenarios!
The future is
now!
Copyright © 2018, Oracle and/or its affiliates. All
rights reserved. |

Virtually all organizations
require their most critical
systems to be highly
available, secure,
compliant
5
100%

Modern Application Stack: where are my data?
Frontend
Middle Tier
Data Tier
rights reserved. |

M S
S
S
S
M
write
clients
read
clients read
clients
write
clients
M o r e
r e a d s ?
M o r e
slaves!
Copyright © 2016, Oracle and/or its affiliates. All rights reserved. | MySQL Innovation Day 2016 -
Redwood Shores, CA, US
7
Yesterday: Asyncronous replication
Read scale-out

C
B
A
C
B
Crash
C
B
A
B is the
new master
Uh Oh! Whew!
8
Yesterday: Asynchronous Replication
Redundancy as a major building block for high availability: If
master crashes, promote slave to master
Limitations: failover and conflict detection should be handled
manually or handled at application level

InnoDB
Cluster
9
App Servers with
MySQL Router
MySQL Group Replication
MySQL Shell
Setup, Manage,
Orchestrate
“A single product — MySQL —
with high availability
and scaling features baked in;
providing an integrated
end-to-end solution
that is easy to use.”

The Components

Requirements (by design)
•Requires InnoDB storage engine.
•Primary key is required on every table.
•Requires global transaction identifiers turned on.
•Optimistic execution: transactions may abort on COMMIT
due to conflicts with concurrent transactions on other
members.
•No concurrent DDL
•No Transaction Isolation Mode “SERIALIZABLE”
•Restrictions on usage of Foreign Keys
11
Wednesday,
September 21, 2016
Oracle Open World 2016 - San Francisco,
California, US

MySQL InnoDB Cluster: Internal Architecture
M
M M
MySQL Connector
Application
MySQL Router
MySQL Connector
Application
MySQL Router
MySQL Shell
HA
Group Replication
12

MySQL Router
rights reserved. |
6
6
•MySQL Router is lightweight middleware that provides
transparent routing
between your application and back-end MySQL Servers.
•MySQL Router also provides High Availability and
Scalability by effectively routing database traffic to
appropriate back-end MySQL Servers.
•The pluggable architecture also enables developers to
extend MySQL Router for custom use cases.

MySQL Router
• Native support for MySQL InnoDB
clusters
– Understands Group Replication topology
– Utilizes metadata schema stored on
each member
• Bootstraps itself and sets up client routing for
the GR cluster
• Allows for intelligent client routing into the GR
cluster
• Supports multi-master and single primary
modes
• Core improvements
Logging, Monitoring, Performance,
Security
rights reserved. |
6
7
App Servers with
MySQL Router
MySQL Shell
Setup, Manage,
Orchestrate

MySQL Shell 8.0.12+
15
A single unified client for all administrative and operations tasks
•Advanced command-line client and code editor for the MySQL
Server
– Supports development & administration for the MySQL Server
– Can be used to perform data queries/update & administration operations
•Interactive multi-language: JavaScript, Python, and SQL
– Naturally scriptable (with development & administrative APIs)
– Both interactive and batch operations
•Supports both Document (CRUD) and Relational models (SQL)
– Modern fluent API for the MySQL Document Store
– Supports the traditional Table results, as well as JSON or Tab separated output
•Exposes full Development and Admin API

MySQL Shell: Admin API
•mysql-js> dba.help()
•The global variable 'dba' is used to
access the MySQL AdminAPI
•Perform DBA operations
– Manage MySQL InnoDB clusters
•Create clusters
•Validate MySQL instances
•Configure MySQL instances
•Get cluster info
•Modify clusters
Database Administration Interface
App Servers with
MySQL Router
MySQL Shell
Setup, Manage,
Orchestrate
16

The core component: MySQL Group Replication
• What is MySQL Group Replication?
“Update everywhere replication plugin for MySQL with built-
in automatic distributed recovery, conflict handling,
group membership and distributed agreement.”
• What does the MySQL Group Replication plugin
do for the user?
– Removes the need for handling server fail-over.
– Provides fault tolerance.
– Enables update everywhere setups.
– Automates group reconfiguration (handling of crashes,
failures, re-connects).
– Provides a highly available replicated database.
– Automatic distributed coordination (protects against split-
brain and message loss).
– Less admin overhead, means more fun time!
App Servers with
MySQL Router
MySQL Shell
Setup, Manage,
Orchestrate

MySQL Group Replication:
Architecture
M M M M M
Replication Group
MySQL Router(s)

MySQL Group Replication: Some Theory Behind It...
•Implementation based in Replicated Database State
Machines
– Group Communication Primitives resemble properties of Databases.
•Deferred update replication: propagate atomically,
check conflicts, eventually apply
– Distributed state machine requires agreed delivery – implies total
order;
– Deterministic certification requires total order delivery.
•Membership Service
– Which servers are participating in the replication group at a given
moment in time? (associated with a logical timestamp [ - view
identifier]).

•Any two transactions on different servers can write to the
same tuple.
•Conflicts will be detected and dealt with.
– First committer wins rule (based on db-versions in writesets)
20
M M M M M
UPDATE t1 SET a=2 WHERE a=1UPDATE t1 SET a=3 WHERE a=1
OK
MySQL Group Replication: Multi Master Automatic
Conflict Detection!

MySQL Group Replication: Automatic distributed
recovery!
•Server that (re)joins the group will automatically synchronize
with the others.
•If a server leaves the group, the others will automatically be
informed.
M M M M M N
ONLINE
RECOVERING

MySQL Group Replication: Single Primary Mode
S S S S P S
Primary
S
Configuration mode that makes a single member act as a
writable master (PRIMARY) and the rest of the members act
as hot-standbys (SECONDARY).
- Failover: the group itself coordinates automatically to figure out
which is the member that will act as the PRIMARY, through a leader
election mechanism.

MySQL Group Replication: Single Primary Mode
S S S S SP
Primary
Configuration mode that makes a single member act as a
writable master (PRIMARY) and the rest of the members act
as hot-standbys (SECONDARY).
- Failover: the group itself coordinates automatically to figure out
which is the member that will act as the PRIMARY, through a leader
election mechanism.

MySQL Group Replication: Major Building
Blocks (1)
M M M M M
MySQL
Server
API
Replication
Plugin
Com. API
Group Com. Engine
2
4

MySQL Group Replication: Major Building Blocks (2)
•Server calls into the plugin through a generic
interface
– (Most of server) internals are hidden from the plugin.
– Some of the semi-sync interfaces were reused.
Others were deployed.
•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.
Replication
Plugin
Com. API
API
MySQL
Server
Group
Comm.System
(Corosync)
Group Com. Engine
2
5

MySQL Group Replication: Major Building Blocks (3)
•The replication plugin is
responsible for
– Maintaining distributed execution
context.
– Detecting conflicts.
– Handling distributed recovery:
•Detect membership changes;
•Donate state if needed;
•Collect state if needed.
– Receiving and handling transactions
from other members.
– Deciding the fate of on-going
transactions.
Com. API
Replication
Plugin
API
MySQL
Server
Group
Comm.System
(Corosync)
Group Com. Engine
2
6

MySQL Group Replication: Major Building
Blocks (4) •The communication API (and
bindings) is
responsible for:
– Abstracting the underlaying
communication engine
from the plugin itself.
– Maping the interface to a specific
communication engine.
Com. API
API
Replicatio
n Plugin
MySQL
Server
Group
Comm.System
(Corosync)
Group Com. Engine
2
7
•The communication engine:
– Variant of Paxos developed at MySQL.
– Building block to provide distributed
agreement between servers.

MySQL Group
Replication
Full Transaction life cycle
5
6

MySQL Group Replication: Performance
4
6

MySQL Group Replication: Performance Comparison
4
7

Setup, Monitoring
and Management

InnoDB Cluster Deployment:
Hardware and Infrastructure Notes
•3, 5, 7 or 9 machines per group
– Isolate machine resources as much as possible
– Limit virtualization layers
– Machines configured for dedicated database server role
•Recommended configuration
– 32-64 vCPUs with fast CPU clock (2.5GHz+)
– SSDs (for data and replication logs)
– High quality network connection between each machine
•Low latency, high throughput, reliable
•Limit routers and hubs as much as possible
•Isolated and dedicated network when possible

Shared Nothing Cluster – Single Data Center
Application Servers
MySQL Router in Stack
MySQL Database Service
Group Replication

Shared Nothing Cluster – Cross Data Center
MySQL Database Service
Group Replication
Data Center 1 Data Center 2
Clients

Geographically Redundant Cluster
Async Replication
Active Data Center Backup Data Center
Clients

Active/Active Multi-Data Center Setup
Async Replication
Regional Data Center
Regional ClientsRegional Clients

Production Deployment Considerations
• Setup: 1 Master (N1), 2 Slaves (N2, N3) → InnoDB Cluster
Method 1 Method 2
- Stop writes on N1
- Wait for N1 and N3 to be in
sync
- Stop and reset replication
setup
- Create InnoDB Cluster
- Clean replication setup
N2 becomes Primary (and
still Slave on different
channel)
- Stop replication on N3 and
add it as secondary of N2
- Stop writes on the Master
(N1)
- Wait for N2 and N3 to be in
sync
- Add N1 to the cluster as
Secondary

MySQL Shell: Configure MySQL Instances
shell> mysqlsh root@localhost
mysql-js> dba.checkInstanceConfiguration(‘localhost:3306’)
mysql-js> dba.configureInstance(‘localhost:3306’)
38

MySQL Shell: Create an InnoDB Cluster
mysql-js> cluster = dba.createCluster(‘NewAppCluster')
mysql-js> cluster.addInstance('root@hanode1:3306')
# mysql 5.7: to persist the config changes on each machine
shell> mysqlsh root@localhost
mysql-js> dba.configureLocalInstance(‘localhost:3306’)
39

MySQL Shell: Add a MySQL Router
shell> mysqlrouter --bootstrap hanode1:3306
shell> mysqlrouter &
shell> mysqlsh root@localhost:6446
40

MySQL Shell: Check Status
shell> mysqlsh root@localhost:6446
mysql-js> cluster = dba.getCluster()
mysql-js> cluster.status()
41

MySQL Shell: Check Status
mysql-js> cluster.status()
{
"clusterName": "mylabcluster",
"defaultReplicaSet": {
"name": "default",
"status": "OK",
"statusText": "Cluster is ONLINE and can tolerate up to ONE failure.",
"topology": {
"hanode1:3306": {
"address": "hanode1:3306",
"mode": "R/W",
"readReplicas": {},
"role": "HA",
"status": "ONLINE"
},
…
42

MySQL Enterprise Monitor
•Native holistic support for Group Replication / InnoDB
clusters
– Topology views
– Detailed metrics and graphs
– Best Practice advice
•Monitoring of MySQL
Routers
43

Conclusion

5.5
More
Enterprise
Features
5.6
Security,
Performance
5.7
JSON,
InnoDB
Cluster
8.0Document
Store
Takeaways: bringing MySQL
into the future
Making MySQL the foundational
layer of your modern
applications
in your
organization
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MySQL InnoDB Cluster: High Availability Made Easy!

MySQL InnoDB Cluster: High Availability Made Easy!

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