Crate kube_leader_election

Crate for implementing leader election in Kubernetes operators

Example

The following example uses a Kubernetes Lease to implement leader election, acquires leadership, waits a little while and steps down again.

use kube_leader_election::{LeaseLock, LeaseLockParams};
use std::time::Duration;

#[tokio::main]
async fn main() -> anyhow::Result<()> {
   std::env::set_var(
       "RUST_LOG",
       std::env::var("RUST_LOG").unwrap_or_else(|_| "info".to_string()),
   );
   env_logger::init();

   // Configure the LeaseLock mechanism
   //
   // One should try to renew/acquire the lease before `lease_ttl` runs out.
   // E.g. if `lease_ttl` is set to 15 seconds, one should renew it every 5 seconds.
   let leadership = LeaseLock::new(
       kube::Client::try_default().await?,
       "default",
       LeaseLockParams {
           holder_id: "simple-lease".into(),
           lease_name: "simple-lease-example".into(),
           lease_ttl: Duration::from_secs(15),
       },
   );

   // Run this in a background task and share the result with the rest of your application
   let _lease = leadership.try_acquire_or_renew().await?;
   // `lease.acquired_lease` can be used to determine if we're leading or not

   log::info!("waiting 5 seconds, then stepping down again");
   tokio::time::sleep(Duration::from_secs(5)).await;

   // To give up leadership, call `step_down`.
   //
   // This will set the current ttl on the lease to 1s and remove the current holder identity,
   // so all other candidates start to race for the lock on the lease.
   leadership.step_down().await?;

   Ok(())
}

Please refer to the examples for more details.

Structs

• LeaseLock
  Represent a LeaseLock mechanism to try and acquire leadership status
• LeaseLockParams
  Parameters to create a LeaseLock lock
• LeaseLockResult
  Result of a try_acquire_or_renew call on a LeaseLock

Enums

• Error