[CONTINT-4726] Add a Kubernetes objects generator

[L3n41c]

What does this PR do?

Add a Kubernetes objects generator.

Motivation

In order to perform performance benchmarks, we need to generate load on the agent.
A form of load for the agent is Kubernetes resources.

Related issues

Additional Notes

[blt]

That this function is created with a macro makes this module hard to follow. I strongly prefer we do not introduce macros into lading. They are tricky to debug, make dealing with type errors a pain and are contrary to the 'naive' style of the project where indirection and abstraction is kept to a minimum.

Structurally I believe you should be able to avoid the use of macros entirely and use an internal enum with functions hung off it. Something like:

#[derive(Debug, Clone)]
pub enum Resource {
    Namespace(k8s_openapi::api::core::v1::Namespace),
    Pod(k8s_openapi::api::core::v1::Pod),
    Deployment(k8s_openapi::api::apps::v1::Deployment),
    Service(k8s_openapi::api::core::v1::Service),
}

impl Resource {
    fn api<K>(&self, client: kube::Client) -> kube::Api<K>
    where
        K: ...
    { ... }

    async fn create(
        &self,
        client: kube::Client,
        number_of_instances: u32,
    ) -> Result<(), Error> { ... }

And then in create you switch on the enum and Kubernetes is written in terms of Resource which also implies you can have one Kubernetes generator handle multiple Resources instead of the current state where you have multiple Kubernetes generators that each handle one resource.

[L3n41c]

I tried to remove the macros in a separate commit to better visualize the differences with and without them: 2686034 (#1392)

I feel that a lot of Resource methods would need to duplicate similar enum switches.

@blt would you mind reviewing 2686034 (#1392) and let me know if it’s correctly implementing your suggestion?

[Copilot]

Pull Request Overview

This PR introduces a new Kubernetes objects generator for performance benchmarking. The generator creates, manages, and optionally recreates Kubernetes resources to simulate load on agents monitoring Kubernetes environments.

• Adds a new kubernetes generator module with support for Node, Namespace, Pod, Deployment, and Service resources
• Implements resource lifecycle management including creation, deletion, and optional recreation based on max lifetime
• Provides configuration options for manifest content, instance count, and resource lifetime management

Reviewed Changes

Copilot reviewed 5 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
lading/src/generator/kubernetes.rs	Core implementation of the Kubernetes generator with resource management logic
lading/src/generator.rs	Integration of the Kubernetes generator into the main generator framework
lading/Cargo.toml	Added Kubernetes client dependencies (kube, kube-core, k8s-openapi, either)
examples/lading-kubernetes.yaml	Example configuration demonstrating various Kubernetes resource types
CHANGELOG.md	Documentation of the new feature

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