Why do I need Docker?

Question

System administration

Good afternoon!
I’m not completely in the subject, and to be honest, I didn’t really go into it, but why would Docker be needed other than as a toy for the admin?
I'm sooooo not catching up at all, and therefore I would like to ask you to explain to me like a fool:
Here is my standard stack:
* NodeJS
* MongoDB
* Nginx
* RabbitMQ
* Memcached
* GO // This is less common, but sometimes I write native utilities on it that Node pulls
All data in Mongo, RabbitMQ and on the local folders of the Node program (she sometimes writes logs in them, saves processed data that does not fit into the mona) is very important, even after the crash, i.e. losing and forgetting is not an option.
But at the same time, contrary to the nodes, there are sometimes a lot of the same type (up to 100), and each time it is not very convenient to raise a virtual machine, and killing it is not very convenient. And at the same time, sometimes it would be necessary to raise another 50 workers, let it be on holidays or weekends, when there is a lot of data, but at night, on the contrary, kill them, so that the Amazon money would not be idle and hawal.
And here he himself is a stupid question:
* Should I teach, docker. And use it for yourself?
* Do I need to shove everything into containers, or run bases and Rabbit as usual on virtual machines?
* Is it possible to make private containers with Node-worker. Since configs are wired in them, they are blocked from going to the public hub.

Answer 1

Why do you need Docker?
Personally, I use:
- Docker for environment management (both for dev and prod)
- Docker-distribution for storing built container images
- Docker-compose for container orchestration on the target machine (for dev it's my machine, for prod it's a remote server)
- Docker-machine for managing remote machines (it will put the docker where it needs to be and all that)
- Docker-swarm (I don't use it yet, there was no need) - for container orchestration in the classter, with failover, etc. Since docker-machine can be configured so that he would also create instances (for example, droplets on DO), then you can organize a fully automated system with a certain level of fault tolerance.
In general, you can not log in via SSH at all for deployment. Wildly convenient, especially when there are a lot of projects and a lot of servers.

Answer 2

If you ask the question "Why do I need XXX" then you don't need XXX. Docker is needed in order to play with it, obviously you prefer other toys.