https://github.com/hendrikmaus/kube-leader-election

A crate to implement leader election for Kubernetes workloads in Rust.
https://github.com/hendrikmaus/kube-leader-election

kubernetes leader-election rust-lang

Last synced: 14 days ago
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A crate to implement leader election for Kubernetes workloads in Rust.

• Host: GitHub
• URL: https://github.com/hendrikmaus/kube-leader-election
• Owner: hendrikmaus
• License: mit
• Created: 2021-07-21T19:58:07.000Z (over 3 years ago)
• Default Branch: master
• Last Pushed: 2024-10-11T09:00:58.000Z (about 1 month ago)
• Last Synced: 2024-10-26T16:54:38.890Z (19 days ago)
• Topics: kubernetes, leader-election, rust-lang
• Language: Rust
• Homepage: https://docs.rs/crate/kube-leader-election
• Size: 145 KB
• Stars: 47
• Watchers: 2
• Forks: 6
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# Kubernetes Leader Election in Rust

![CI workflow](https://github.com/hendrikmaus/kube-leader-election/actions/workflows/ci.yaml/badge.svg)

![crates.io version](https://img.shields.io/crates/v/kube-leader-election)

[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)

This library provides simple leader election for Kubernetes workloads.

```toml

[dependencies]

kube-leader-election = "0.37.0"

```

## Example

Acquire leadership on a Kubernetes [`Lease`](https://kubernetes.io/docs/reference/kubernetes-api/cluster-resources/lease-v1/) called `some-operator-lock`, in the `default` namespace and promise to renew the lock every 15 seconds:

```rust

let leadership = LeaseLock::new(

    kube::Client::try_default().await?,

    "default",

    LeaseLockParams {

        holder_id: "some-operator".into(),

        lease_name: "some-operator-lock".into(),

        lease_ttl: Duration::from_secs(15),

    },

);

// Run this in a background task every 5 seconds

// Share the result with the rest of your application; for example using Arc

// See https://github.com/hendrikmaus/kube-leader-election/blob/master/examples/shared-lease.rs

let lease = leadership.try_acquire_or_renew().await?;

log::info!("currently leading: {}", lease.acquired_lease);

```

*Please refer to the [`examples`](https://github.com/hendrikmaus/kube-leader-election/tree/master/examples) for runnable usage demonstrations.*

## Features

- Kubernetes `Lease` locking, similar to [client-go's leaderelection](https://pkg.go.dev/k8s.io/client-go/tools/leaderelection)

## Kubernetes `Lease` Locking

A very basic form of leader election without fencing, i.e., only use this if your application can tolerate multiple replicas acting as leader for a short amount of time.

This implementation uses a Kubernetes `Lease` resource from the API group `coordination.k8s.io`, which is locked and continuously renewed by the leading replica. The leaseholder, as well as all candidates, use timestamps to determine if a lease can be acquired. Therefore, this implementation is volatile to datetime skew within a cluster.

Only use this implementation if you are aware of its downsides, and your workload can tolerate them.

## Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

## License

[MIT](https://choosealicense.com/licenses/mit/)