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Do I Need Kubernetes?

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Re: Do I Need Kubernetes?

#61

Post by heroic »

save_ferris wrote: post #12
gravypod wrote: post #6

> Run your applications in Docker from day 1 (with docker-compose it’s as valuable for dev as it is for production) and think carefully before letting your applications store local state. I think this is the key take away for many startups. Get it so you: 1. Have a single-command way to bring up your entire backend 2. That command can run on your dev machine 3. You document all of the settings for your containers and…

> people were amazed by the productivity gains Yeah, docker compose is great for running distributed apps locally when everything “just works”. The problem is that it also impedes development when the compose setup isn’t fully optimized. I work on dockerized rails apps, and whenever a new dependency is added, it can take 15 minutes to rebuild the image, which completely breaks my flow. Docker also creates a ton of da…

Split the dockerfile into 3 parts. builder image for gems. builder image for assets(nodejs and stuff). copy code from disk, gems from image one, assets from image two, into the third image. you will end up saving HUGE time

Re: Do I Need Kubernetes?

#62

Post by gravypod »

abatilo wrote: post #42
gravypod wrote: post #6

> Run your applications in Docker from day 1 (with docker-compose it’s as valuable for dev as it is for production) and think carefully before letting your applications store local state. I think this is the key take away for many startups. Get it so you: 1. Have a single-command way to bring up your entire backend 2. That command can run on your dev machine 3. You document all of the settings for your containers and…

There are a lot of projects these days that aim to use Kubernetes as a docker-compose environment. I personally use http://skaffold.dev/ with either a local Kubernetes cluster built with https://github.com/rancher/k3d or https://github.com/kubernetes-sigs/kind . I think there's a very easy argument to be made that says that running K8s locally is overkill, but what I will say is that if you run your applications loca…

`kind` and `k3d` are great but I don't think their aimed at being a developer friendly cluster from what I understand. They both require a lot of tweaking and setup to make them look like their a managed kube cluster (LB, storage, ingresses, etc). I wish there was something that could create a kube cluster that:

    1. sets up automatic port forwards to my host system
    2. handles ingresses by binding port :80 on my system
    3. provisions PVs for you when you create PVCs and respects retention policies 
    4. Allows you to select from a monitoring stack and only require that you supply configurations for dashboards/alerts that can be 1:1 applicable to production so devs can debug dashboards/alerts locally.
`kind` is targeting itself as being "a real kubernetes implementation"

`k3d` is targeting itself as being Rancher's kubernetes implementation so if you buy into all of the Rancher tooling it'd be a great option.

Re: Do I Need Kubernetes?

#63

Post by gravypod »

spost wrote: post #23

I work for a startup whose product is small (half a dozen servers, if relatively beefy ones) clusters that will be run on-prem by customers, at least sometimes in a low-to-no-touch capacity. Most of our application components are micro-ish services that are run on all hosts in the cluster for either extra capacity or fault tolerance. We currently run everything on mesos/marathon, but are looking to switch away from i…

There's a great talk from Chick-Fil-A about running kube clusters on bare metal [0]. I'm also going to be taking up a similar problem soon-ish and I'm also looking into Container Linux/derivations for doing a lot of the bare metal, updating, and rollbacks they talk about here. If anyone here has worked on this project, or similar, it would be awesome to get in touch!

[0] - https://www.youtube.com/watch?v=8edDcy3oeUo

Re: Do I Need Kubernetes?

#64

Post by tilolebo »

abatilo wrote: post #42
gravypod wrote: post #6

> Run your applications in Docker from day 1 (with docker-compose it’s as valuable for dev as it is for production) and think carefully before letting your applications store local state. I think this is the key take away for many startups. Get it so you: 1. Have a single-command way to bring up your entire backend 2. That command can run on your dev machine 3. You document all of the settings for your containers and…

There are a lot of projects these days that aim to use Kubernetes as a docker-compose environment. I personally use http://skaffold.dev/ with either a local Kubernetes cluster built with https://github.com/rancher/k3d or https://github.com/kubernetes-sigs/kind . I think there's a very easy argument to be made that says that running K8s locally is overkill, but what I will say is that if you run your applications loca…

Talking about kind and k3s, does anyone know how to load a local docker image into a k3d cluster?

The command is supposed to be: 'k3d image import --cluster myCluster image:tag', but it fails with "Failed to start exec process in node 'k3d-myCluster-tools'"

On kind it works fine with 'kind load docker-image --name myCluster image:tag'.

I'm using WSL2.

Re: Do I Need Kubernetes?

#65

Post by overgard »

I think one of the underrated parts of using something like Kubernetes early (or even w/ simpler orchestrators like swarm or rancher), is that it encourages (and sometimes enforces) architecture best practices from the start. IE, you won't be storing state locally, you'll be able to handle servers being randomly killed, you'll already have horizontal scaling, etc. In my experience the hard part of migrating to containers in a legacy app is when they break those constraints, especially around local state and special servers. It's easier to do these things sooner rather than later, and the constraints kubernetes places on you aren't that hard to work around if you design it in from the start.

I good reason not to use kubernetes though is if you know your app is probably never going to scale, or if it's the kind of thing that can scale very well on a single machine, or if it's not primarily based on http communication. (I wouldn't write a real time game server in kubernetes, for instance, because I doubt it'd really help with a primarily UDP workload that is likely going to be attached to one server)

Re: Do I Need Kubernetes?

#66

Post by onei »

tln wrote: post #58
save_ferris wrote: post #12

Earlier quoted context omitted.

> people were amazed by the productivity gains Yeah, docker compose is great for running distributed apps locally when everything “just works”. The problem is that it also impedes development when the compose setup isn’t fully optimized. I work on dockerized rails apps, and whenever a new dependency is added, it can take 15 minutes to rebuild the image, which completely breaks my flow. Docker also creates a ton of da…

First, make sure you only copy your Gemfile and maybe Gemfile.lock before running bundle install. If you aren't that could explain the amount of bloat since every build will create some large layers with no chance of re-use. You could try making your own base image that installs your gems. Eg, copy your Dockerfile to Dockerfile.base. Remove everything after the bundle install, and build to say app-base:latest. Then c…

I'd suggest using targets within the dockerfile combined with buildkit. Targets allow you to build multiple images from one dockerfile or have multiple distinct stages that depend on one another. Using buildkit means you can build target dependencies in parallel.

Personally, I found having multiple intermediate dockerfiles more confusing than helpful, so having an easy to follow, centralised build made life a lot easier for me, especially if you produce multiple images that are pretty similar at the base.

Re: Do I Need Kubernetes?

#67

Post by Axsuul »

I need Kubernetes since we're outgrowing Docker Swarm. Docker Swarm has a lot of issues we deal with on a constant basis so it's becoming quite painful.

Can anyone suggest a good migration guide from Docker Swarm -> Kubernetes?

Re: Do I Need Kubernetes?

#68

Post by k__ »

This sounds like people try to compare K8s with what was before and sure, that all holds true.

You get all of this with serverless (be it with managed services or FaaS), with reduced (albeit not zero) complexity compared to K8s.

Re: Do I Need Kubernetes?

#69

Post by ezekiel68 »

gravypod wrote: post #27
JamesSwift wrote: post #21

Earlier quoted context omitted.

I prefer to take it one abstraction further and setup a makefile where the default `make` brings up the app. This makes it so you can rework the runtime as you see fit and nothing changes. It also doesn't require you to jump into docker immediately, and gives a good extension point for various 'helper script' workflows that you will always have.

Makefiles are nice in theory but don't scale well to team members who don't know how to use make. If your team is full of experienced C/C++ devs then this will probably work great for you. If you are working with a bunch of android/javascript/etc developers who've never seen make, and who haven't exercised the skillset of reading through 3-decade-old email threads to find answers, you'll find that the only thing you'…

Not to pile on -- and I'm sure there would be exceptions -- but I've worked with some large and dynamic (employee churn) dev teams and it's always been worth it in my cases, so far, to burn a half day with new people to get them comfortable with Makefiles (and how to fix the common errors when editing them). Teams I've been on have used them for python, ruby, node, Java and Rust[1] codebases (across the years). It's definitely language-agnostic enough on its own. Oh! And the same Makefile is used in the CI/CD pipeline, to make the entire process more likely to be repeatable by our automation tools.

[1] Yes, our Makefiles sometimes call docker/npm/ant/maven/gradle/cargo under the hood. Its been worth it, in my experience. One syntax on all projects to set up the workspace, refresh dependencies, deploy to dev env, clean, etc.

Re: Do I Need Kubernetes?

#70

Post by daralthus »

thom wrote: post #9
gravypod wrote: post #6

> Run your applications in Docker from day 1 (with docker-compose it’s as valuable for dev as it is for production) and think carefully before letting your applications store local state. I think this is the key take away for many startups. Get it so you: 1. Have a single-command way to bring up your entire backend 2. That command can run on your dev machine 3. You document all of the settings for your containers and…

Can I ask people who _don't_ use Kubernetes and maybe have architectures built on proprietary cloud services: how do you manage this?

Use Pulumi or Terraform.
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