The Art of Designing Distributed Systems: Tips and Techniques

Distributed System is a software system that consists of multiple independent computers that communicate with each other over a network. Distributed systems are designed to improve performance, reliability, and scalability by distributing the workload across multiple computers and by providing a single point of access to the system.

Distributed systems can be used to build a wide range of applications, including web applications, microservices architectures, distributed databases, and more. They can be deployed on-premises or in the cloud, and can be implemented using various technologies and protocols such as HTTP, TCP/IP, and message queues.

System design is the process of designing and planning the architecture of a complex system, such as a software application or a network of interconnected devices. It involves identifying the requirements and constraints of the system, evaluating different design options, and selecting the most appropriate solution. In this article, we will explore some key concepts and techniques in system design, and provide an example of how to design a simple distributed system using these principles.

Scope & Requirments

One of the key challenges in system design is defining the scope and requirements of the system. This involves identifying the goals and objectives of the system, as well as the constraints and limitations that must be considered.

For example, if you are designing a software application, you might need to consider factors such as

• Performance
• Scalability
• Reliability
• Security
• Maintainability.

Similarly, if you are designing a network of interconnected devices, you might need to consider factors such as connectivity, latency, bandwidth, and power consumption.

Designing

Once you have defined the scope and requirements of the system, you can begin evaluating different design options. This might involve creating diagrams and models to visualize the components and interactions of the system, as well as conducting analysis and simulations to evaluate the performance and reliability of different design choices. Some common techniques used in system design include

• Object-oriented design
• Data modeling
• Network architecture design

Simple distributed system

As an example of how these concepts might be applied in practice, let’s consider the design of a simple distributed system that stores and retrieves data from a distributed database. The system might have the following requirements and constraints:

• Low Latency: The system must be able to store and retrieve data from a distributed database with low latency.
• Scaling: The system must be able to scale horizontally to handle a large number of concurrent requests.
• Fault-tolerant: The system must be fault-tolerant, with no single point of failure.
• Security: The system must be secure, with data encrypted at rest and in transit.

Most Important Components of a Disturbted System

Load Balancer

A load balancer to distribute incoming requests across a pool of servers.

Load balancers use various algorithms to determine how to distribute incoming traffic, such as round-robin, least connections, or source IP hash. They may also use techniques such as health checks to ensure that only healthy servers receive traffic, and may provide features such as SSL offloading, content-based routing, and session persistence.

AWS ELB (Elastic Load Balancer) & Azure are the most used load balancers

Database Cluster

A cluster of servers running a database engine, such as MySQL or MongoDB, to store and retrieve data from the database. You can use Amazon Aurora (One of the main features of Amazon Aurora is its ability to scale horizontally, which means that you can add more capacity to the database by simply adding more database instances. This makes it easy to handle large amounts of data and a high number of concurrent database connections.)

Caching

A cache layer, such as Redis/Elastic Cache/Memcached/Apache Ignite, etc. This is used to store frequently accessed data in memory for faster retrieval.

Message Queue (Decoupling)

A message queue, such as RabbitMQ / SQS / Kafka / Azure Service Bus, to decouple the database servers from the load balancer and improve fault tolerance.

High-level design Implementation

To implement this design, we can use the following steps:

1. Deploy a load balancer, such as Amazon Elastic Load Balancing, to distribute incoming requests across the server cluster.
2. Set up a cluster of servers running a database engine, such as Amazon RDS / Aurora, to store and retrieve data from the database.
3. Install and configure a cache layer, such as Amazon ElastiCache, on each server to store frequently accessed data in memory.
4. Set up a message queue, such as Amazon SQS, to decouple the database servers from the load balancer and improve fault tolerance.
5. Configure security measures, such as SSL/TLS for data in transit and encryption at rest, to protect the data stored in the system.

This is just one example of how system design principles and techniques can be applied to design a distributed system. There are many other considerations and trade-offs that might come into play depending on the specific requirements and constraints of the system. The key is to carefully define the scope and requirements of the system, evaluate different design options, and select the most appropriate solution based on the trade-offs involved.

Once the system is designed, the next step is to implement and deploy the system. This might involve writing code to implement the various components and interactions of the system, testing the system to ensure it meets the requirements and constraints, and deploying the system to a production environment.

In the case of our distributed system example, this might involve the following steps:

Code & Config

Write code to implement the load balancer, server cluster, cache layer, and message queue, using languages and frameworks such as Go, Python, or Java.

Testing

Test the system to ensure it performs as expected and meets the requirements and constraints, using techniques such as unit testing, integration testing, and load testing.

Deploy

Deploy the system to a production environment, such as the Amazon Web Services (AWS) cloud, using tools and services such as AWS CloudFormation or AWS Elastic Beanstalk.

Monitor

Monitor the system to ensure it is running smoothly and to identify and resolve any issues that may arise, using tools such as AWS CloudWatch or New Relic.

Once the system is deployed, it is important to continue maintaining and improving the system to ensure it meets the evolving needs and requirements of the users. This might involve updating the system with new features, fixing bugs, and optimizing performance.

In summary, system design is a complex and multifaceted process that involves identifying the requirements and constraints of the system, evaluating different design options, and implementing and deploying the selected solution. By following best practices and using the right tools and techniques, you can design and build systems that are scalable, reliable, and secure, and that meet the needs of your users.

In the future blogs will go deeply into these concepts

• Scaling (Vertical vs Horizontal)
• Load Balancer
• Message Queues (SQS)
• Disturbted Databases
• Caching

Bye for now.

Happy Learning!