CODEWITHSUNDEEP
dockerarchitecturemicroservices
Zoinky
Zoinky

Reputation: 5019

multiple micro services sharing same database SERVER (One container, multiple dabases)

Is it good practice to have multiple services connect to the same database server but each having their own database. I guess having one Postgres instance is better than each service/container having their own instance.

My question is that should each service:

  1. run in their own container with db server instance in the same container
  2. run in their own container and the db for that service run on a separate container just for the db (multiple db containers/one per service)
  3. one db SERVER, multiple databases, one container for all databases and all services connect this container/db server

I understand that each service should have their own db, but does that also means they should be completely decoupled even server wise.

I guess the reason I want to have one db SERVER is so that resources are not "wasted" as multiple instance of db server running

I also understand that having one server will mean that all services will coupled hardware wise

Upvotes: 2

Views: 2589

Answers (3)

Rych Emrycho
Rych Emrycho

Reputation: 85

Well, you can consider these:

1) If your service doesn't care about your database server, I mean like, for Service A it must be MongoDB, Service B must be Ms. SQL Server, etc.

Then you can go with this setup:

One Database Server -> with, Multiple Databases -> where, One Database for each Service.

2) But, if you find it does matter, as I describe below:

Service A -> Postgres

Service B -> Postgres

Service C -> Ms. SQL Server

Service D -> MongoDB

then you will have 3 database servers where Service A & B will share the same Postgres database server (containing 2 databases, one for Service A, one for Service B) and Service C will have 1 Ms. SQL Server (containing, 1 database) also Service D MongoDB server (containing 1 database).

Usually, you will find this case while you are working with different teams (which handle each service) and each team decides on their own choices.

Upvotes: 0

Arnon Rotem-Gal-Oz
Arnon Rotem-Gal-Oz

Reputation: 25909

Yes it is ok to have multiple services on the same server.

The deployment configuration should be guided by your operational needs (cost, performance monitoring etc.) as long as the services are decoupled you'd have the freedom to move the data around based on your operational needs

Upvotes: 0

David Maze
David Maze

Reputation: 159091

It doesn’t really matter. Modern infrastructures tend not to care about the overhead of running multiple copies of the same service. Since database I/O can often be a critical performance point, you might find it more manageable to not share a database, so that you can put databases under heavier load on dedicated and/or larger hardware.

(Also consider running your database(s) on dedicated hardware, not under Docker: they’re the one thing you must back up, and you’ll update them much less often than the rest of your application stack, so their lifecycle is fundamentally different from a disposable Docker container. If you’re using a public cloud service that offers a managed database service and are willing to pay for it, that can also be a very reasonable option.)

Whatever you decide, you almost definitely need to make all of the parameters (host, database, username, password) configurable, usually via environment variables. (I see too many SO questions that have host names hard-coded in source code.) You should be able to deploy the same image with different options in development, test, and production environments, which will generally have different host names.

Upvotes: 3

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