﻿---
title: Kubernetes LeaderElection Provider
description: Provides the option to enable leaderelection between a set of Elastic Agents running on Kubernetes. Only one Elastic Agent at a time will be the holder...
url: https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/4409/reference/fleet/kubernetes_leaderelection-provider
products:
  - Elastic Agent
  - Fleet
---

# Kubernetes LeaderElection Provider
Provides the option to enable leaderelection between a set of Elastic Agents running on Kubernetes. Only one Elastic Agent at a time will be the holder of the leader lock and based on this, configurations can be enabled with the condition that the Elastic Agent holds the leadership. This is useful in cases where the Elastic Agent between a set of Elastic Agents collects cluster wide metrics for the Kubernetes cluster, such as the `kube-state-metrics` endpoint.
Provider needs a `kubeconfig` file to establish a connection to Kubernetes API. It can automatically reach the API if it’s running in an InCluster environment (Elastic Agent runs as Pod).
```yaml
providers.kubernetes_leaderelection:
  #enabled: true
  #kube_config: /Users/elastic-agent/.kube/config
  #kube_client_options:
  #  qps: 5
  #  burst: 10
  #leader_lease: agent-k8s-leader-lock
  #leader_retryperiod: 2
  #leader_leaseduration: 15
  #leader_renewdeadline: 10
```

<definitions>
  <definition term="enabled">
    (Optional) Defaults to true. To explicitly disable the LeaderElection provider, set `enabled: false`.
  </definition>
  <definition term="kube_config">
    (Optional) Use the given config file as configuration for the Kubernetes client. If `kube_config` is not set, `KUBECONFIG` environment variable will be checked and will fall back to InCluster if it’s not present.
  </definition>
  <definition term="kube_client_options">
    (Optional) Configure additional options for the Kubernetes client. Supported options are `qps` and `burst`. If not set, the Kubernetes client’s default QPS and burst settings are used.
  </definition>
  <definition term="leader_lease">
    (Optional) Specify the name of the leader lease. This is set to `elastic-agent-cluster-leader` by default.
  </definition>
  <definition term="leader_retryperiod">
    (Optional) Default value 2 (in sec). How long before Elastic Agents try to get the `leader` role.
  </definition>
  <definition term="leader_leaseduration">
    (Optional) Default value 15 (in sec).  How long the leader Elastic Agent holds the `leader` state.
  </definition>
  <definition term="leader_renewdeadline">
    (Optional) Default value 10 (in sec). How long leaders retry getting the `leader` role.
  </definition>
</definitions>

The available key is:

| Key                                | Type   | Description                                                                                                                            |
|------------------------------------|--------|----------------------------------------------------------------------------------------------------------------------------------------|
| `kubernetes_leaderelection.leader` | `bool` | The value of the leadership flag. This is set to `true` when the Elastic Agent is the current leader, and is set to `false` otherwise. |


## Understanding leader timings

As described above, the LeaderElection configuration offers the following parameters: Lease duration (`leader_leaseduration`), Renew deadline (`leader_renewdeadline`), and Retry period (`leader_retryperiod`). Based on the config provided, each agent will trigger Kubernetes API requests and will try to check the status of the lease.
<note>
  The number of leader calls to the K8s Control API is proportional to the number of Elastic Agents installed. This means that requests will come from all Elastic Agents per `leader_retryperiod`. Setting `leader_retryperiod` to a greater value than the default (2sec), means that fewer requests will be made towards the Kubernetes Control API, but will also increase the period where collection of metrics from the leader Elastic Agent might be lost.
</note>

The library applies [specific checks](https://github.com/kubernetes/client-go/blob/master/tools/leaderelection/leaderelection.go#L76) for the timing parameters and if those are not verified Elastic Agent will exit with a `panic` error.
In general: - Leaseduration must be greater than renewdeadline - Renewdeadline must be greater than retryperiod*JitterFactor.
<note>
  Constant JitterFactor=1.2 is defined in [leaderelection lib](https://pkg.go.dev/gopkg.in/kubernetes/client-go.v11/tools/leaderelection).
</note>


## Enabling configurations only when on leadership

Use conditions based on the `kubernetes_leaderelection.leader` key to leverage the leaderelection provider and enable specific inputs only when the Elastic Agent holds the leadership lock. The below example enables the `state_container` metricset only when the leadership lock is acquired:
```yaml
- data_stream:
    dataset: kubernetes.state_container
    type: metrics
  metricsets:
    - state_container
  add_metadata: true
  hosts:
    - 'kube-state-metrics:8080'
  period: 10s
  condition: ${kubernetes_leaderelection.leader} == true
```