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0 pointsStavrosK8y ago0 comments

From what I saw, it's not very easy to have a deployment with multiple applications on the swarm, is that wrong?

For example, I have ten applications, and each requires a database, a redis instance, a celery instance and two web workers. Dokku lets me deploy these independently of each other, but uses the same nginx instance and proxies them transparently.

As I understand it, Swarm has no notion of multiple projects. Each swarm is running a single deployment, where all containers are equal, is that correct?

Basically, Dokku is a self-hosted Heroku, which is what I need (I want to be able to easily create a project that I can run semi-independently of the others on the same server). My understanding is that, to do that with Swarm, I'd have to have a single termination container that would connect to every app, but apps wouldn't be any more segregated than that. Maybe I'm complicating things, though. Have you used Swarm for such a use case?

I tried the official tutorial, but couldn't get it to work, as the instructions appeared outdated and didn't work for single-host deployments, and were geared more towards Windows and Mac than Linux. Would you happen to have a good "getting started" document? All my apps are already using docker-compose.

EDIT: Also, a machine that's a manager doesn't want to join the swarm as a worker as well, that's why I'm saying that it doesn't appear good for single-server deployments:

> Error response from daemon: This node is already part of a swarm. Use "docker swarm leave" to leave this swarm and join another one.

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2 comments · 2 top-level

sandGorgon8y ago

the docker stack deploy command does automatic diffing of which services have changed. So your deploys are automatically optimized. This is generally the philosophy of Swarm vs kubernetes - everything is built in. You can argue this is less powerful, but in general it works brilliantly. In so far as separating out the different "applications", you simply put them on a separate overlay network (encrypted if you want).

Also, if you are dead-set on making them entirely separate, every separate "application" is a separate "Stack". So you can stack deploy them separately.

If I had to do what you just told me - single nginx proxying to two different "applications" - i would do this. 1. stack 1 - application 1 + network 1 2. stack 2 - application 2 + network 1 3. stack 3 - nginx + network 1

now you can deploy any of them independently. You can make this even more sophisticated by having each stack on a different overlay network (encrypted as well). And nginx bridging between them.

Not sure why you are facing problem with the official tutorial - btw, a manager is a worker ;) I have a fairly large dev swarms on a single node.

faisyl8y ago

Swarm is nice as-is but is, but really shines with support like docker-swarm-proxy. Please check out http://proxy.dockerflow.com/. It allows for automatic service discovery as well as routing/termination etc. It also runs as a stack on swarm itself. Supports custom TLS termination as well as SNI routing.

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