When your servo motors start "chatting": How do microservices communicate with each other?

Imagine you are assembling a robotic arm, with each joint controlled by an independent servo. The finger motors need to know the angle of the wrist, and the wrist motors have to coordinate with the elbow - how do they "talk"? In the world of mechanical systems, this conversation is often done through hardwiring or centralized controllers. But in the digital realm, when two microservices need to collaborate, things become a bit like having two strangers coordinate their actions in real time on opposite sides of the world.

The bridge from mechanical to digital

In mechanical projects, we are used to using physical signals - voltage, pulse, encoder feedback. But in the world of microservices, communication becomes invisible packets. Some people may directly think of the simplest way: let service A directly call the interface of service B. Just like when you press a button, the light comes on. This can work, but only if Service B is always available, the network is always open, and the speeds of the two match. The reality is that networks will be delayed, services will be restarted, and traffic will spike. Direct calls often turn into "I called you, but you didn't hear", and then the whole process gets stuck.

So in the past few years, everyone has begun to change their thinking - instead of letting services "call" directly, let them "send emails." That is, through a message queue or event-driven approach, service A sends the message to an intermediate platform, and service B picks it up when it is free. It's like leaving a note in the workshop: "Motor 3 temperature warning, please deal with it." The colleague responsible for processing will adjust it when he sees the note, without worrying about whether the two people are present at the same time.

In a mechanical analogy, this method is a bit like installing a small mailbox for each motor. Is your mailbox full? Then no new messages can be saved for the time being. But at least messages will not be lost and the system will be more decoupled. But a new question arises: What if there are too many “paper notes” to handle? If a message is particularly urgent, how can I jump in line?

walk intokpowersolution perspective

existkpowerIn our technical practice, we found that many customers' initial designs are like bundling all the wires together - it works in the short term, but maintenance is like a mess. Communication between microservices should not be so fragile. We tend to steer toward a model that is closer to "neural reflex": asynchronous, event-driven, but with low latency on the critical path.

For example, you have a service that collects servo motor vibration data, and another service that is responsible for predictive maintenance. The vibration data service does not have to wait for the prediction service to respond. It only needs to send the data packets, mark the priority, and it has completed its job. The prediction service may retrieve the data after a few milliseconds, or it may process it later due to tight computing resources. But the vibration data service does not block, it continues to collect the next group. The entire system is like a flexible workshop, with each workstation operating autonomously and indirectly collaborating through a conveyor belt (message pipeline).

Someone asked: "What if the message pipe itself fails?" This goes back to redundant design. A good microservices communication architecture will allow messages to be backed up on multiple paths, like backup transmission rods in a mechanical system.kpowerWhen assisting customers with deployment, a "publish/subscribe" model is often suggested - one service publishes an event, and multiple related services can subscribe to it and process it as needed. This avoids a single point of dependency and makes it easier to scale.

Why does this sound simple, but is so easy to do?

Because real-life scenarios are rarely as simple as "two services". More often than not, there are dozens or even hundreds of services intertwined with each other. A triggers B, B triggers C and D, and the result of C flows back to A... At this time, if every communication uses synchronous waiting, the system will be like a joint tightened by too many screws, stiff and prone to collapse.

So we often joke that designing microservice communication is like arranging a dance for a group of servos - you can't let each motor wait for the complete signal of one motor, otherwise the dance will get stuck. You have to let them listen to the same music (event flow), each step to the same beat, occasionally glance at the location of their companions (status query), but run autonomously most of the time.

In Kpower, we will first help customers draw data flow diagrams, just like drawing mechanical transmission diagrams. Which communications require real-time synchronization (such as emergency shutdown signals), which ones can tolerate delays (such as log uploads), which ones guarantee order (such as step instructions), and which ones can be processed out of order (such as data sampling). After categorizing, match different communication protocols and tools. This is not a one-size-fits-all approach, but like a gear set, each meshing point must have the right tooth profile and speed.

Sometimes, less is more

Interestingly, when you ask experienced mechanical designers how to simplify the system, they will often say: "Reduce the transmission link." The same is true in microservice communication - not all services need to talk directly. Paths can be converged via an aggregation service (API gateway) or event bus. This is like adding a distribution box to complex machinery, making the main line clearer and making maintenance easier.

Kpower found during project review that an over-designed communication layer is often more troublesome than insufficient. For example, for "insurance", a message queue is added between each service. As a result, more than a dozen message chains have to be tracked during operation and maintenance. Later, we adjusted our strategy to give priority to ensuring high reliability of core links, while non-core links were allowed to be downgraded. This actually makes the system more robust, just like a good machine - using quenched steel for key parts and ordinary alloys for secondary parts, the overall cost performance and reliability are improved.

So, next time you worry about how microservices "chat", you might as well think about how you design mechanical collaboration: clarify the division of labor, establish a clear signal protocol, leave some buffer space, and add more insurance for key parts. Leave the rest to partners like Kpower to help you turn your blueprint into a stable reality. After all, whether it’s machinery or code, good communication is the cornerstone of smooth operation.

Established in 2005, Kpower has been dedicated to a professional compact motion unit manufacturer, headquartered in Dongguan, Guangdong Province, China. Leveraging innovations in modular drive technology, Kpower integrates high-performance motors, precision reducers, and multi-protocol control systems to provide efficient and customized smart drive system solutions. Kpower has delivered professional drive system solutions to over 500 enterprise clients globally with products covering various fields such as Smart Home Systems, Automatic Electronics, Robotics, Precision Agriculture, Drones, and Industrial Automation.