Cluster, distributed and microservice concepts and differences

Concept :

Cluster is a physical form , Distributed is a way of working .

• Distributed ： A business is divided into several sub businesses , Deployed on different servers
• colony ： The same business , Deployed on multiple servers

1： Distributed means that different businesses are distributed in different places . Clustering refers to clustering several servers together , Achieve the same business .

Every node in the distribution , Can do cluster . Clusters are not necessarily distributed .

give an example ： For example, sina.com , More people visited , He can make a group , Put a response server in front , The following servers complete the same business , If there is a business visit , Response server to see which server load is not very heavy , Which one will be given to complete .

And distributed , Understand... In a narrow sense , It's similar to clustering , But it's more loosely organized , It's not like clustering , There is an organization , A server is down , Other servers can be on top .

Every distributed node , All complete different businesses , A node is broken , Then this business is not accessible .

2： In short , Distributed is to shorten the execution time of a single task to improve efficiency , Cluster is to improve the efficiency by increasing the number of tasks per unit time .

for example ： If a task consists of 10 Sub task composition , Each subtask is executed separately 1 Hours , To perform this task on a server 10 Hours .

Using distributed solutions , Provide 10 Servers , Each server is responsible for only one subtask , Regardless of the dependencies among subtasks , It takes only an hour to finish the task .( A typical example of this working mode is Hadoop Of Map/Reduce Distributed computing model ）

The cluster scheme is adopted , It also provides 10 Servers , Each server can handle this task independently . Suppose there is 10 A task arrives at the same time ,10 Servers will work at the same time ,1 Hours later, ,10 Tasks completed at the same time , such , Come and see , still 1 Finish a task in hours ！

---

A good design should be a combination of distributed and cluster , First distributed and then clustered , The specific implementation is to split the business into many sub businesses , Then cluster deployment is carried out for each sub business , In this way, if there is a problem with each sub business , The whole system will not be affected at all .

in addition , Another concept is similar to distributed computing , That's it Microservices .

Microservice is an architectural style , A large complex software application consists of one or more microservices . Each microservice in the system can be deployed independently , The microservices are loosely coupled . Each microservice only focuses on accomplishing one task and accomplishing it well . In all cases , Each task represents a small business capability .

 

difference :

1. Distributed

Divide a large system into multiple business modules , Business modules are deployed on different machines , Each business module interacts with each other through the interface . The way to distinguish between distributed systems is based on different machines and different services .

above ：service A、B、C、D Business components , adopt API Geteway Business access .

notes ： Distributed business needs to be well managed .

For distributed transactions, please refer to ： Distributed transaction solution of microservice Architecture

2. Cluster pattern

Cluster mode is that different servers deploy the same set of services for external access , Load balancing of services . The way to distinguish clusters is based on whether the services of multiple servers deployed are the same .

notes ： Cluster mode needs to be done well session share , Make sure that in the process of switching between different servers, it will not be caused by not getting session And discontinue the service .

General configuration Nginx* Implementation of load container based on XML ： Static resource cache 、Session Sharing can come with ,Nginx Support 5000 Concurrency .

3. Is distributed a micro service ？

The answer is yes . Microservices It means to split the module into an independent service unit and realize data interaction through the interface .

4. Microservice architecture

Microservices are designed to avoid the upgrade and BUG Affect the existing system business . The subtle difference between microservices and distribution is , Microservice applications are not necessarily distributed on multiple servers , It can also be the same server .

 

Distributed and micro service framework Very similar , It's just that the way of deployment is different .