kamal custom builder for docker

[alexohre]

hello folks,
the title might not really convey the full information I wanted but here is the drill

so I have been playing with the kamal deployment tool recently and found it very interesting but at thesame time the build takes much time and requires more memory from my machine to process it. then I stumbled upon docker build cloud which build way faster than the local build.

here is the stats with my cloud build
initial build was 1ms 21s
the second build was just 28s

so now I was thinking if there is a way I can tell kamal to use a specific builder in my local machine that is connected to my build cloud instead of creating a new build all the time I run kamal setup

something like Kamal setup --builder custom-build-name to make the deploy process faster

and if its not an option now I think someone could make it possible soon

and finally a big thanks to the Rails community for all the good work so far.

[nickhammond]

Nice find! Kamal currently supports remote builders(https://kamal-deploy.org/docs/configuration/builders/#remote-configuration) but the builder name is kamal specific. A new option to the builder configuration would probably be needed or you might be able to create a context that points at Docker cloud and Kamal would just pick it up. Here are some builder examples as well https://kamal-deploy.org/docs/configuration/builder-examples/.

I'm putting the full build step here for documentation to help with a new configuration option PR.

Here's a full Docker cloud setup and build:

 docker login
 docker buildx create --driver cloud ORG/BUILDER_NAME
 docker buildx build --builder cloud-ORG-BUILDER_NAME --tag IMAGE .

Kamal creates a build context using a method based on the builder called builder_name
https://github.com/basecamp/kamal/blob/main/lib/kamal/commands/builder/native/remote.rb#L39

    def builder_name
      "kamal-#{config.service}-native-remote"
    end

So most likely a new driver(cloud?) that creates the build context with the cloud driver, creates a build context with that driver, and then builds with the cloud context.

[alexohre]

wow, thanks for the detailed response

at last, someone finally understood me

 docker login
 docker buildx create --driver cloud ORG/BUILDER_NAME
 docker buildx build --builder cloud-ORG-BUILDER_NAME --tag IMAGE .

I have done the above already, it is just for me to tell Kamal to use my cloud-orgname builder to make life easy for my poor machine

[nickhammond]

@alexohre Sorry, that's not a working example it's just the steps that would need to happen in a PR.

[alexohre]

that would be awesome if it would be on the next update of kamal to speed things a bit faster

…

On Tue, Aug 27, 2024 at 4:23 AM Nick Hammond ***@***.***> wrote: @alexohre <https://github.com/alexohre> Sorry, that's not a working example it's just the steps that would need to happen in a PR. — Reply to this email directly, view it on GitHub <#914 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ALNPNJVJJCMGHY5CZUY53E3ZTPWLVAVCNFSM6AAAAABNETTBE6VHI2DSMVQWIX3LMV43URDJONRXK43TNFXW4Q3PNVWWK3TUHMYTANBVHAYTKMA> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[nickhammond]

It looks like this almost works, but needs a few small tweaks to get it going.

builder:
  arch: amd64
  driver: cloud nickhammond/hotdonuts

  INFO [551c2126] Running docker buildx inspect kamal-local-cloud nickhammond/hotdonuts as n@localhost
  ERROR (SSHKit::Command::Failed): docker exit status: 256
docker stdout: Nothing written
docker stderr: ERROR: "docker buildx inspect" requires at most 1 argument.
See 'docker buildx inspect --help'.

Usage:  docker buildx inspect [NAME]

Inspect current builder instance