[Kamal 2]: Container Conflicts for Staging and Production Application Running on Same Host

[mike-weiner]

I've got a basic web application running on a DigitalOcean Droplet. I have both the production and staging instances of the application on the same host. I realize that's atypical. It's a non-critical, side project that I don't need redundancy for nor do I need to add complexity for 2 different hosts.

I'm hitting a weird edge case that I'm looking for some advice on.

When I've got a new build ready to go out to staging, I do a kamal deploy -d staging and it builds the container with the current commit (let's say that is 123), builds the image, and exposes port abcd for my web application. That deploys perfectly.

24 hours later I'll do a kamal deploy to push the changes out to production. Kamal re-builds the container with the same commit (123) but it exposes a different port, let's say efgh for production. That process then overwrites that image in my registry with a build that now exposes port efgh instead of abcd.

The production instance deploys fine, but if I ever need to restart the staging instance, it will go and re-pull the 123 container image which is now built to expose the incorrect port.

Is there a better way to achieve this kind of setup to avoid this? Or is this a limitation that I'm going to need to live with?

Thank you!

[tuladhar]

Are you using same service: name for both your staging and production?

[mike-weiner]

Yes, I am.

[tuladhar]

The service name must be unique, you can prefix or suffix with environment name, e.g: myapp-staging

[mike-weiner]

Here is my config: https://github.com/mike-weiner/kenyonwx/tree/main/config

The problem that I have is that I do a kamal deploy -d staging and that pushes both a latest-staging and a commit (57c85d4062d5de024719fde5c4b42adf3aef3c67) image to Docker.

I then run kamal deploy and that pushes both a latest and a commit (57c85d4062d5de024719fde5c4b42adf3aef3c67) image to Docker that overwrites the previous 57c85d4062d5de024719fde5c4b42adf3aef3c67 tagged image. And that changes the exposed port in the image.

Kamal uses the commit image to deploy. So this overwriting of the commit image tag is a problem as the port changes between my staging and production environment.

[tuladhar]

Hmm...in that case, this might help.

kamal deploy -d staging --version staging