Safely Drain a Node in Kubernetes

--- reviewers: - davidopp - mml - foxish - kow3ns title: Safely Drain a Node content_type: task weight: 310 ---  This page shows how to safely drain a {{< glossary_tooltip text="node" term_id="node" >}}, optionally respecting the PodDisruptionBudget you have defined. ## {{% heading "prerequisites" %}} This task assumes that you have met the following prerequisites: 1. You do not require your applications to be highly available during the node drain, or 1. You have read about the [PodDisruptionBudget](/docs/concepts/workloads/pods/disruptions/) concept, and have [configured PodDisruptionBudgets](/docs/tasks/run-application/configure-pdb/) for applications that need them.  ## (Optional) Configure a disruption budget {#configure-poddisruptionbudget} To ensure that your workloads remain available during maintenance, you can configure a [PodDisruptionBudget](/docs/concepts/workloads/pods/disruptions/). If availability is important for any applications that run or could run on the node(s) that you are draining, [configure a PodDisruptionBudgets](/docs/tasks/run-application/configure-pdb/) first and then continue following this guide. It is recommended to set `AlwaysAllow` [Unhealthy Pod Eviction Policy](/docs/tasks/run-application/configure-pdb/#unhealthy-pod-eviction-policy) to your PodDisruptionBudgets to support eviction of misbehaving applications during a node drain. The default behavior is to wait for the application pods to become [healthy](/docs/tasks/run-application/configure-pdb/#healthiness-of-a-pod) before the drain can proceed. ## Use `kubectl drain` to remove a node from service You can use `kubectl drain` to safely evict all of your pods from a node before you perform maintenance on the node (e.g. kernel upgrade, hardware maintenance, etc.). Safe evictions allow the pod's containers to [gracefully terminate](/docs/concepts/workloads/pods/pod-lifecycle/#pod-termination) and will respect the PodDisruptionBudgets you have specified. {{< note >}} By default `kubectl drain` ignores certain system pods on the node that cannot be killed; see the [kubectl drain](/docs/reference/generated/kubectl/kubectl-commands/#drain) documentation for more details. {{< /note >}} When `kubectl drain` returns successfully, that indicates that all of the pods (except the ones excluded as described in the previous paragraph) have been safely evicted (respecting the desired graceful termination period, and respecting the PodDisruptionBudget you have defined). It is then safe to bring down the node by powering down its physical machine or, if running on a cloud platform, deleting its virtual machine. {{< note >}} If any new Pods tolerate the `node.kubernetes.io/unschedulable` taint, then those Pods might be scheduled to the node you have drained. Avoid tolerating that taint other than for DaemonSets. If you or another API user directly set the [`nodeName`](/docs/concepts/scheduling-eviction/assign-pod-node/#nodename)

This document explains how to safely drain a node in Kubernetes using `kubectl drain`, respecting PodDisruptionBudgets (PDBs) to ensure workload availability during maintenance. It outlines the prerequisites, including configuring PDBs and understanding unhealthy pod eviction policies. The process involves using `kubectl drain` to evict pods gracefully, allowing for safe node maintenance like kernel upgrades or hardware maintenance. It also highlights considerations for system pods and the `node.kubernetes.io/unschedulable` taint.