微服务和数据库：mongodb docker-如何设置容器

Question

I'm creating an app using micro-services architecture, using mongodb, nodejs, and docker.

I read that, each micro-services should have his own database, and I guess each microservice live in a separate container. So I guess 1 micro-service = 1 container

But what about their respecting databases, should they also live in the same micro-service container ? So it would be 1 micro-service = 1 container (with 1mongo image + 1nodejs image)

Or is it more like 1micro-service = 1container(app) + 1container(database)

I'm trying to implement this way right now, but each time I down my container, the volume is removed...

So i'm wondering, how should I set up my database and containers to properly apply a micro-service architecture

Thanks in advance for any feedback

Answer 1

You should run one service in at least one container. In the situation you're describing, for basically exactly the reasons you describe, it's generally important to run your databases in separate containers (you don't want to have to destroy and restart your database just because you updated application code).

(Imagine you were running things purely locally: the situation is analogous to your application starting and stopping the database on its own. It's administratively a little easier at first glance, but if the application vs. database is having trouble, or if you need to scale things, or ..., you'd be much happier directly managing the database.)

This Kubernetes question has a good higher-level picture: in that question there are a half-dozen services, plus one of them has a backing database, and these are each running in separate containers (in that question separate Kubernetes Deployments/StatefulSets/Pods). Logically "service B plus its backing database" might be a single unit but you'd deploy the two halves in separate containers.