Kube is an umbrella-crate for interacting with Kubernetes in Rust.

Overview

Kube contains a Kubernetes client, a controller runtime, a custom resource derive, and various tooling required for building applications or controllers that interact with Kubernetes.

The main modules are:

• client with the Kubernetes Client and its layers
• config for cluster Config
• api with the generic Kubernetes Api
• derive with the CustomResource derive for building controllers types
• runtime with a Controller / watcher / reflector / Store
• core with generics from apimachinery

You can use each of these as you need with the help of the exported features.

Using the Client

use futures::{StreamExt, TryStreamExt};
use kube::{Client, api::{Api, ResourceExt, ListParams, PostParams}};
use k8s_openapi::api::core::v1::Pod;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
// Infer the runtime environment and try to create a Kubernetes Client
let client = Client::try_default().await?;

// Read pods in the configured namespace into the typed interface from k8s-openapi
let pods: Api<Pod> = Api::default_namespaced(client);
for p in pods.list(&ListParams::default()).await? {
println!("found pod {}", p.name());
}
Ok(())
}

For details, see:

• Client for the extensible Kubernetes client
• Api for the generic api methods available on Kubernetes resources
• k8s-openapi for documentation about the generated Kubernetes types

Using the Runtime with the Derive macro

use schemars::JsonSchema;
use serde::{Deserialize, Serialize};
use serde_json::json;
use validator::Validate;
use futures::{StreamExt, TryStreamExt};
use k8s_openapi::apiextensions_apiserver::pkg::apis::apiextensions::v1::CustomResourceDefinition;
use kube::{
api::{Api, DeleteParams, ListParams, PatchParams, Patch, ResourceExt},
core::CustomResourceExt,
Client, CustomResource,
runtime::{watcher, utils::try_flatten_applied, wait::{conditions, await_condition}},
};

// Our custom resource
#[derive(CustomResource, Deserialize, Serialize, Clone, Debug, Validate, JsonSchema)]
#[kube(group = "clux.dev", version = "v1", kind = "Foo", namespaced)]
pub struct FooSpec {
info: String,
#[validate(length(min = 3))]
name: String,
replicas: i32,
}

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
let client = Client::try_default().await?;
let crds: Api<CustomResourceDefinition> = Api::all(client.clone());

// Apply the CRD so users can create Foo instances in Kubernetes
crds.patch("foos.clux.dev",
&PatchParams::apply("my_manager"),
&Patch::Apply(Foo::crd())
).await?;

// Wait for the CRD to be ready
tokio::time::timeout(
std::time::Duration::from_secs(10),
await_condition(crds, "foos.clux.dev", conditions::is_crd_established())
).await?;

// Watch for changes to foos in the configured namespace
let foos: Api<Foo> = Api::default_namespaced(client.clone());
let lp = ListParams::default();
let mut apply_stream = try_flatten_applied(watcher(foos, lp)).boxed();
while let Some(f) = apply_stream.try_next().await? {
println!("saw apply to {}", f.name());
}
Ok(())
}

For details, see:

• CustomResource for documentation how to configure custom resources
• runtime::watcher for how to long-running watches work and why you want to use this over Api::watch
• runtime for abstractions that help with more complicated Kubernetes application

Examples

A large list of complete, runnable examples with explainations are available in the examples folder.