Kustomize

Octopus supports the deployment of Kubernetes resources through the Kustomize step.

This step allows you to source your Kustomize files from git, perform variable substitutions based on your environment and/or tenant and finally apply the changes to your Kubernetes clusters.

Kustomize introduces a template-free way to customize application configuration that simplifies the use of off-the-shelf applications.

Recommended usages for this step

We list a few different scenarios below to help you figure out what is the best setup for you to deploy your applications to a Kubernetes cluster with Octopus.

When you use Kustomize for one application configuration

1. Multiple overlays
   This is the recommended usage if you are already using Kustomize and just want Octopus to orchestrate the deployment. In this scenario, our recommendation is to use .env files with Octopus variable substitution syntax, so we can replace secrets and any other data managed via Octopus variables. These .env files are then used by secretGenerator and/or configMapGenerator.
   Everything else is defined in the kustomization.yaml files directly, and overlays should match the same environment structure defined in Octopus itself.

2. Single overlay for Octopus
   In this scenario, you may define two overlays, one being for local use outside Octopus, so you can test your yaml files. The other overlay is used exclusively by Octopus.
   In the Octopus overlay, you add variable substitution syntax directly into kustomization.yaml and any other yaml files in the overlay folder, as well as .env files.
   This scenario is better suited for customers with many environments and/or tenants, where customizations are needed for each target.

3. A mix of both
   This would be the ideal scenario when you have a small number of environments and many tenants.
   In this scenario, you model your overlays based on the environments, with the different settings hardcoded in the kustomization.yaml file, and you use Octopus substitution syntax to define the different tenant properties in kustomization.yaml file.
   Again as in the previous scenarios, we would use .env files for secrets via secretGenerator.

When you use Kustomize to template configurations for many applications

1. A mix of both — templates
   You can go beyond configuration for a single application with Octopus and Kustomize. Imagine you have a hundred applications you deploy to Kubernetes. Some of them might have universal traits, like a group of API applications or a group of databases. Therefore, parts of the configuration will be universal for all the apps or a group of apps. There likely be app-unique parameters (like a container image).
   You can combine overlays and Octopus variables to create and use one template for all the apps. In this scenario, you would have a set of base files same for all the apps. One or more levels of overlays to add customizations for an app group. You can introduce another layer of overlays for environments. Finally, app-specific parameters (e.g. container images, tags and labels) can be defined in Octopus variables.
   In this scenario, tenant or environment-specific parameters can be added to any overlay. For example, you can add prefixes for tenants; also consider using system variables.

Kustomization file directory

This field must be a path to a directory containing the kustomization.yaml file. During deployment, Kustomize reads the kustomization.yaml file located at this path to perform manifest yaml transforms.
The path is relative to the root of the git repository. When using overlays, ensure the path is to the overlay directory containing kustomization.yaml file.
Also, remember that in Linux workers, the paths are case-sensitive, so it is always good practice to check this.

Substitute Variables in Files

This setting is useful, for example, when you want to put your application specific configuration settings in a .env file and also have the value scoped per environment and/or tenant, see more information regarding variable scoping.
The target file paths are relative to the root of the git repository. Again remember that in Linux workers, paths are case-sensitive, so it is always good practice to check this.
You can use glob patterns to target multiple files. Learn more about glob patterns.

Referencing Container images

From v2.0.2, you are able to add container images as package references directly from the Kustomize step. Image references added in this way can be used via reference package variables.

For example, if you add a container image reference for nginx:

You will then be able to select the version of this container image at release creation time. You can use the referenced nginx container image in your kustomization.yaml file using the following syntax:

# ~/myApp/kustomization.yaml

resources:
- deployment.yaml

images:
- name: nginx
   newTag: #{Octopus.Action.Package[nginx].PackageVersion}

The ”#{Octopus.Action.Package[nginx].PackageVersion}” Octostache expression will be resolved to the selected image version during the deployment.

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Page updated on Sunday, January 1, 2023