Docker Swarm Cluster Complete Guide

https://knowledgepill.it/posts/docker_swarm_compendium/

by lukasbar • 6 years ago

84 39 6 years ago

orf• 6 years ago

Swarm was interesting, but it seems that both SwarmKit and "Classic Swarm" are dead[1][2], with no real activity since 2018.

Kubernetes, for better or for worse, has clearly completely won. Not that this article isn't interesting for it's own sake, but it's just something to consider.

1. https://github.com/docker/swarmkit/graphs/contributors 2. https://github.com/docker/classicswarm/graphs/contributors

sph• 6 years ago

SwarmKit and ClassicSwarm are not "docker swarm", but AFAIK precursors of it until they've been merged into Docker itself.

As a production user of Docker Swarm though, it is effectively dead and I've been planning a migration to k8s ASAP.

justincormack• 6 years ago

Swarmkit is the code that runs "Docker Swarm", it is vendored in to build it. I don't think anyone really uses Classic Swarm any more, and it was a precursor.

zenlot• 6 years ago

That’s very sad to see Docker Swarm declining. I run few production clusters, all are being set up via Ansible and Wireguard for communication. The setup takes only few minutes and runs perfectly fine. It's been running for a while and I haven't had any issues with clusters, as well as it doesn't require maintenance. While Kubernetes is great, it requires a lot of maintenance and setup isn't straightforward. Sometimes you don't need additional complexity and want things just to run and pretty much forget.

moomin2• 6 years ago

I know Mirantis have pledged to continue developing Docker Swarm, but it still strikes me as a pretty risky choice for 2020.

DyslexicAtheist• 6 years ago

I know some companies still using it because they say K8 is too complex (e.g. learning curve) for their needs. It could be appealing to these cases.

moomin2• 6 years ago

Meh, it’s a pain to install, but that can be automated, and a pain to get your head around, but the only features you really need for basic usage are service and deployment.

On the other hand, most of the books on it are spectacularly bad.

lukasbar• 6 years ago

This guide can help people that want to pass DCA exam from Docker Inc.

kfk3• 6 years ago

I am looking into this now. Basically it’s either this or the super hard Kubernetes right? I find it hard to believe that we don’t have a middle ground?

scrappyjoe• 6 years ago

K3s is pretty approachable.

tyingq• 6 years ago

Mesos and K3S are two other choices in that space.

dblooman• 6 years ago

There is AWS ECS as well

sandGorgon• 6 years ago

There is the k3s distro of kubernetes

auspex3• 6 years ago

Kubernetes really isn't as difficult as you might think. Early on it was "hard" because most people were learning containers as well as Kubernetes.

Also how that we have managed services like EKS, GKE, AKS it's really straight forward to learn.

I would suggest start with a GKE cluster and deploy nginx.

kfk3• 6 years ago

There are many managed services, which is great, but how does this work when your storage is somewhere else? For instance I might decide to put the storage (postgres and minio) on a cheap Hetzner dedicated server, how would this work with EKS? I am especially trying to understand doing analytics and ML with dask.distributed. I think running compute on managed Kubernetes with storage inside another server could (hybrid?) should be ok, but I haven't figured this part yet.

jordanbeiber4• 6 years ago

Nomad + Consul.

Used it for years in prod - just awesome.

I’ve also used k8s extensively and nomad/consul is more ”open” and less opinionated.

If you also manage some form of legacy infrastructure and VMs, consul is hard to ignore.

Two go-binaries - you’re up in minutes for a test drive.

kfk3• 6 years ago

I looked into Nomad, did not understand much. I am pretty OK with docker and docker-compose, me and my team use docker to develop data workflows in python locally. So out of Docker I am much less comfortable. For instance, would JupyterHub for Kubernetes run on Nomad?

https://zero-to-jupyterhub.readthedocs.io/en/latest/customiz...

heipei• 6 years ago

sigh I've almost given up nudging folks on here to give Nomad a spin. It's so easy to deploy and play with, heck you can run a client and server with a single go binary on your local machine. If you compare that to all the hundreds of different (and soon-to-be-deprecated) installation instructions for k8s, k8s feels like a joke at best, or an evil plot at worst to get everyone to use hosted k8s. Honestly, people use hosted k8s because you need a full-time person/team to run it, so in the end, even though k8s is Open Source, Google (and AWS) still win...

Nevermind that Nomad is fast, easy to grasp, very concise and can run non-Docker workloads. Oh well...

gas9S9zw3P9c3• 6 years ago

I don't understand why people think Kubernetes is "hard" - I find it quite straightforward and the documentation is excellent. I've been running my side projects on a single k8s clusters and rarely have issues.

Yes, there is a learning curve. It's not a Heroku where you enter one command and it just works. You'll need to spend a few days to become familiar with the basics concepts. And it may take weeks grasp the advanced concepts. But it's less complexity than learning something like a new programming language.

You'll probably get back the time you invested. Things like deploying production-ready application with a single command using e.g. Helm is quite powerful and can save you money over using managed services.

ernststavrob• 6 years ago

Kubernetes is "hard" when you're not running on the cloud. The solutions for persistent storage and networking are a mess when you're running on self-hosted infrastructure.

woudsma• 6 years ago

This was also my question/frustration. Kubernetes is not so easy to learn, especially if your focus is on other programming projects and you just want a easy and scalable personal server setup.

I've created a tool called 'Swarmlet' over the past few weeks, which tries to mimic Dokku, so it combines git and Docker Swarm mode for easy app deployments. With some services included like Traefik for routing and automatic SSL using Let's Encrypt, with Consul as a distributed secrets store. https://github.com/swarmlet/swarmlet

Definitely not production-ready, and quite some things to do, but it's a nice POC which actually works for me.

belzebalex2• 6 years ago

Docker Swarm is a marvel. It's super easy to use yet does the job very simply.

auspex3• 6 years ago

On the surface. Easy to setup a simple use case but long term has a similar learning curve to Kubernetes for a production deployment.

readyoubestbook• 6 years ago

Maybe I am missing something or underestimating the complexity of a k8s deployment, but we have been running Swarm in production for a while now and it was/is still a breeze. So what would you consider the complexities of running Swarm in production - I would then like to look into these - as a means of being ahead of the curve of complexity...

winxton• 6 years ago

Agreed. It's my go to for smaller projects and what I recommend for those who don't want to spend more than a day figuring out how to deploy their pet project as it's a logical progression from docker-compose in dev to a production environment.

https://dockerswarm.rocks is better for a more complete, production-ready setup guide.

Docker Swarm Cluster Complete Guide

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