CSDN's annual technology feast "SDCC 2015 China Software Developers Carnival" will be held in Beijing from November 19-21, 2015。

The lecturer we interviewed in this issue is Wang Xiaoxue, a taxi-hailing architect from Kuaishou，He has worked at Alibaba for 4 years。Established Kuaidi taxi basic service team from scratch，In charge of research and development、Introduced many basic frameworks and services，Promote fast architecture upgrade，From stability、Availability、Performance、Security、Monitoring multiple aspects and systematically building a fast and high-availability architecture。For high-concurrency distributed system architecture、Real-time data processing、Have relatively deep experience in network communications and Java middleware。

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Wang Xiaoxue: I worked in Shenzhen for 4 years after graduation，Then worked at Alibaba for 4 years，Fast taxi-hailing job at the beginning of 2014，Responsible for basic services and middleware in Kuaidi’s basic R&D department，For example, distributed message、Service、Wireless open platform、Data platform, etc.，Participated in the real-time computing platform、Monitoring、Security、Construction of data architecture，There are other things，Hosted the technical architecture of multiple large-scale marketing activities of Kuaishou。

After the merger of Kuaidi and Didi，According to the division of labor of the group，Recent period，More than a dozen people in the basic R&D department of Yuankuai have all changed their work directions，The focus behind the basic R&D department is the group’s big data architecture、Online real-time data processing and machine learning。This is a new challenge for us，So our current work focus and learning direction is in this aspect。

About areas of concern，Currently I pay more attention to real-time computing、Machine Learning、Three general directions of containers and virtualization，It can be regarded as the hot topic and trend in this industry in the future。

About the accumulation 188bet sports betting app download of technology，Before working at Alibaba, I was mainly responsible for enterprise systems，Although there is no big traffic and performance challenge，But for demand analysis、Product Thinking、There are still some requirements for scalability design。I have experienced searches on Alibaba、Wireless、Work on high-traffic Web systems and other aspects，I also like learning and thinking，Have in-depth research on many middleware source codes of Alibaba，In high-concurrency and large-traffic distributed system architecture、Java middleware (e.g. distributed RPC、Message、Communication、Container、Template engine, etc.)、Some accumulation in real-time/streaming computing and storage，Have in-depth research on Storm and HBase。

2, What is your understanding of architecture？And how do you define architect？

Wang Xiaoxue: I will talk about architecture and architect separately:

In fact, I rarely talk to others about architecture and what architects should do，Because this topic is more likely to cause a war of words，But when you ask this question, let me tell you my humble opinion。

I think many people have vague definitions of architecture，I will only share my personal views here，No architecture can solve all problems，But the big guiding principles are always there，The architectural points in my opinion are very simple，In fact each expansion is a big topic:

Availability: This is the most important，The system is unavailable and everything is cloudy。There are many points to consider here，For example single point、Performance bottleneck、Possible risks、Quickly detect faults、Quickly locate the cause of the problem, etc.

Extensibility: Based on a high degree of reuse abstraction，Able to meet business needs quickly and flexibly

Scalability: Whether the system service capability can be linearly improved as machines are added

Security: Do not give outsiders the opportunity to exploit loopholes

Technology stack: in a company，Too many language choices or too many architecture choices in the same field，Not a good thing，Unless it is absolutely necessary，Otherwise, huge costs will be spent on internal system integration，Because the language is different，Many things are difficult to reuse，It is also difficult to concentrate on having a deep grasp of a certain language ecology，This is not necessary。This does not mean that architects should not learn more programming languages，But pay attention to the cost and internal friction of multi-language development within the company，The current taxi-hailing system of Kuaishou is mainly based on Java，Also using python、golang、c，But it’s basically tool development。

The following are some principles that I think architects should adhere to when designing。

Business is king：Technology is just a means，Business is fundamental，This sentence may be a bit of a blow to technical people，But this is the truth。Don’t use technology for the sake of playing technology，To solve practical problems，Producing technical value directly or indirectly。

Divergent thinking: Architecture is not just about solving problems。No matter how big or small or simple or complex，Some points must be considered: such as single points、Performance bottleneck、Possible risks、Quickly detect faults、Quickly locate the cause of the problem、Quickly respond to business needs。

Modest design:The architecture is constantly optimized iteratively。Especially in the Internet industry，Full of opportunities，Also full of a lot of uncertainty，Business often requires rapid trial and error，The development speed is also quite fast。Don’t take it for granted to design a large and comprehensive plan，Hope to solve all problems，But it should follow the business scenarios and development，Adhering to some basic design principles while，Solving the most important problems。

3,What qualities do you think make an excellent architect？

Wang Xiaoxue: Excellent architect = an excellent programmer + half product manager + half project manager。

Corresponding ability: solid technology，Better product thinking，Good communication and management skills。

4,It’s been fast in the past few years，What are the node events of technical architecture？Can you discuss the stability at each stage、Availability、Performance、Security、Explain the fast high-availability architecture from many aspects such as monitoring。And as an architect，What are the priorities of your work？

Wang Xiaoxue: You are asking several questions in one sentence，And they are all quite complicated，Let me tell you briefly，More details will be shared。Kuaidi’s taxi-hailing technology is roughly divided into three stages: basic functions are available、Core link performance optimization、Systematic architecture design。Kuaidi Taxi’s technical architecture has been systematically designed since April 2014。

We split the system according to business domains，Achieved service-oriented transformation，The previous fast systems were all in one big project，Core functions and non-core functions affect each other，The stability is not very good，After servitization, each business system is independent，Can be developed separately、Release、Expansion，The stability and development efficiency of the system have been greatly improved。

We have also done a lot of things in terms of overall system capacity planning，We stress tested the capacity limit of the online system，Record system indicators at various levels through monitoring，188bet online sports betting Be able to estimate more accurately whether we need to expand or shrink，So in the face of large-scale marketing activities or rapidly growing business volume，We can plan the service capabilities of the system in advance。

We eliminated all single points，Carefully checked the fault recovery capabilities of each node，For example, after the network is disconnected and reconnected，Whether this node or component can work properly，review the JVM configuration of each application and perform targeted GC optimization。

We are also doing a lot of transformation on the data level，Sub-database and sub-table、Data synchronization platform based on binlog、Real-time data center based on HBase。

Tell me briefly。Network level，We use Alibaba Cloud Shield to prevent DDos attacks。The application has done basic XSS、CSRF、SQL injection and other prevention。In terms of wireless request access，We built a wireless gateway，Visitor IP、User IDs have traffic limits，Capacity protection for backend services。All logins to our internal systems require verification by real employee mobile phones。We have built a risk control platform，Combating cheating。

We collected logs from the entire network，And concatenate the logs on the request link through the identifier，Real-time indexing and querying through ElasticSearch，Greatly improves the efficiency of fault location。

We built our own real-time computing platform，We have built a monitoring platform on top of this platform，We can know the operation status and resource overhead of each system at the minute level，Know the business data of the current time，For example, the number of passengers issued in this minute、The number of orders received by drivers、Payment volume, etc.。You can see historical data，You can observe the graph of the selected time period。

Our entire basic R&D team has made a lot of efforts in this process，Everyone worked together to do a lot of things，Also achieved good results。My main job here is basic services and middleware，Because the upper-level transformation must have reliable support from the lower-level，For example NIO communication、File Storage、Distributed Coordination Service、Service Framework、Distributed message、Configuration Center、Data synchronization、Wireless gateway, etc.，Promote the implementation of these basic services in business systems；In addition, we also work with the CTO and the person in charge of basic R&D to formulate the company's technical plan，Participate in the design of other basic research and development work，Participate in the optimization of some application architecture。

5,Can you please briefly introduce some architectural features of Kuaidi’s overall architecture？

Wang Xiaoxue: High-frequency geographical location calculation；A large number of TCP long connection communications；Large amount of data storage；The system has high real-time requirements，There are very few scenes that can be cached，The fault must be located quickly；We must always face fraudulent orders、Attack and other issues。

6,Kuaiti has been established，While business is developing rapidly，The size of the R&D team has also undergone amazing changes，As a team builder from scratch，What is the biggest challenge？and，What is the composition of the R&D team you are responsible for now？

Wang Xiaoxue: The biggest challenge is not solving system problems，But looking for suitable talents。

Basic R&D is divided into: middleware and basic services，Business Structure，Data architecture，Monitoring，Operation and Maintenance。Although I have done a lot of things，In fact, Kuaishou’s basic R&D team has very few people，There are only 20 people in the entire basic R&D team including operation and maintenance，But most of them came at the end of last year or just this year，This includes 7 fresh graduates recruited from our school。There were only 10 people during the hardest time last year: Director of Basic R&D，2 people in middleware and basic services，Business structure 1 person，2 people in data architecture (including DBA)，Monitor 1 person，There are 3 people in IT and operation and maintenance，I am responsible for middleware and basic services，The monitoring turned out to be with me too，Later, I was really too busy and split it off，There are only 5 people below me now。We worked very hard last year，It’s normal to get off work early in the morning，Often stay up all night，Although everyone has a clear division of labor，But help each other and encourage each other，Forged a very deep brotherhood。

7,Today，How do you arrange your learning of new technologies、R&D team management、Programming、Life and other times？

Wang Xiaoxue: I have been writing code，Not for practice，It is the real encoding，Do some core designs and review plans。Just put it briefly，Communicating with classmates during coding and team days，In fact, there is no team management at all，We are all very reliable and mature engineers，Very self-driven，I just pay attention to everyone’s work and study direction，Of course I also do some logistical work:) For example, introducing girlfriends to team members；Study something you are interested in at night；Life is on weekends。I think this arrangement is okay。

8,The topic you want to share at this SDCC 2015 conference is？

Wang Xiaoxue: Kuaidi Taxi Architecture Practice。In the process of Kuai’s growing up from 188bet sports betting app download childhood to adulthood，The road we have traveled，The pitfalls we have stepped on，Our smile，Our cry，I am willing to share it with you sincerely，To all colleagues who are struggling on the road of entrepreneurship。

9,What are you most looking forward to seeing at SDCC 2015？

Wang Xiaoxue: Containers and virtualization；Online learning；The practical practice of startup companies。

Architects should fight on the front line。It is not necessary to solve all problems in detail，But stay sensitive to business，Otherwise, you sit in a high hall and discuss the truth，How can you design a down-to-earth solution to solve the problem？

Architects should understand the business。Architects are the link between business and technology，Only by fully understanding the business can we solve the business pain points。

Architects should make trade-offs。Architectural design is actually an art of balance，There is no fixed pattern to determine which solution is the optimal solution，Many things have two sides，The choice between pros and cons depends on the problem scenario and business development status。

The SDCC 2015 China Software Developer Carnival organized by CSDN will be held in Beijing from November 19th to 21st，This conference covers: new databases、Programming language、Tools and Platforms、Products and Design、Front-end development、Algorithm、WeChat development、Architecture Practice、Safety and other nine major points forum，Well-known foreign lecturers will share the best practices in their fields。