Getting started with Message Oriented Middleware

1、 What is message middleware

Make use of efficient and reliable messaging mechanism for platform independent data exchange ;

And the integration of distributed system based on data communication ;

By providing messaging and message queuing models , It can expand communication between processes in a distributed environment ;

2、 Application scenarios of message middleware

Cross system data transfer 、 Peak clipping of high concurrent traffic 、 Data asynchronous processing … wait

3、 Common message middleware

ActiveMQ、RabbitMQ、Kafka、RocketMQ

4、 Design idea of Message Oriented Middleware

agreement 、 Persistence mechanism 、 Message distribution strategy 、 High availability 、 Highly reliable

5、 What is the protocol

A protocol is a set of agreements that computers follow when communicating with each other , All follow the same agreement , Computers can communicate with each other . A protocol is a set of agreements that computers follow when communicating with each other , All follow the same agreement , Computers can communicate with each other .

Three elements of agreement ：

grammar : That is, the structure or format of data and control information ;
semantics : That is, what kind of control information needs to be sent , What actions to complete and what responses to make ;

sequential ( Sync ): That is, a detailed description of the sequence of event implementation

Message middleware commonly used protocol :OpenWire、AMQP、MQTT、Kafka、OpenMessage

MQTT agreement （RabbiMQ、ActiveMQ）：

MQTT (Message Queuing Telemetry Transport) Message queuing telemetry transmission is IBM Developed an instant messaging protocol , An important part of the architecture of the Internet of things .

characteristic ： Light weight 、 Simple structure 、 Fast transmission 、 No transaction support 、 No persistence related design

Application scenarios ： It is suitable for those with limited computing power 、 Low bandwidth 、 The scene of network instability .

Open Message agreement （RocketMQ）

OpenMessaging It was initiated by Ali in the last year or two , With Yahoo 、 Drops travel 、Streamlio The distributed message middleware, which was founded by companies such as 、 Application development standards in the field of stream processing . It is the first international standard in the field of distributed messaging launched globally in China .
characteristic ： Simple structure 、 Fast parsing 、 With transaction design 、 Persistent design

Kafka agreement （kafka）

Kafka The protocol is based on TCP Binary protocol . Messages are separated by length , It consists of some basic data types .
characteristic ： Simple structure 、 Fast parsing 、 No transaction design 、 Persistent design

6、 Common persistence methods

	ActiveMQ	RabbitMQ	Kafka	RocketMQ
file system	Support	Support	Support	Support
database	Support	/	/	/

7、 Common message oriented middleware distribution strategies

	ActiveMQ	RabbitMQ	Kafka	RocketMQ
Publish subscribe	Support	Support	Support	Support
Poll distribution	Support	Support	Support	/
Fair distribution	/	Support	Support	/
retransmission	Support	Support	/	Support
Message pull	/	Support	Support	Support

8、 High Availability Mechanism

High availability It refers to the ability of the product to perform the specified function under the specified conditions and within the specified time or time interval .

When there's a lot of business , A message oriented middleware server may not meet the requirements , Therefore, message oriented middleware is required to be able to be deployed in clusters , To achieve high availability .

Master-Slave The deployment of master-slave shared data

Master-Slave Master slave synchronous deployment mode

Broker-Cluster Multi master cluster synchronous deployment mode

Broker-Cluster Multi master cluster forwarding deployment mode

Master-Slave And Broker-Cluster combination

9、 What is high reliability

High reliability means that the system can operate continuously without failure . For example, a system never crashes 、 Report errors , Or collapse 、 The probability of reporting errors is low , That is high reliability .
In the high concurrency business scenario , If you can't guarantee the high reliability of the system , The damage will be very serious .
Ensure the high reliability of message middleware , Consider from the following aspects

Reliable message transmission ： Through the protocol to ensure the correctness of data analysis between systems .

Reliable message storage ： To ensure the storage reliability of messages through persistence .