When draining Istio pods some nodes may not drain because they have a replica count of 1, while 3 or
more replicas are required. In order to avoid this, you should set the minimum replica count for each
property to at least 3.
When backing up and draining Istio nodes you may see errors like:
kubectl drain` failed to evict and reschedule pods to another node due to PodDisruptionBudget definitions:
===
NAMESPACE NAME MIN AVAILABLE MAX UNAVAILABLE ALLOWED DISRUPTIONS AGE
istio-system istio-ingressgateway 1 N/A 2 5d11h
istio-system istio-pilot 1 N/A 2 5d11h
===
For istio-ingressgateway and istio-pilot you can set the
istio.ingressgateway.replicaCountMin and istio.pilot.replicaCountMin
properties to 3 or higher. See the
Configuration properties reference,
istio.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-26 UTC."],[[["\u003cp\u003eVersion 1.6 of the Apigee hybrid documentation is end of life, and users should upgrade to a newer version.\u003c/p\u003e\n"],["\u003cp\u003eTo prevent draining issues with Istio pods, set the minimum replica count for properties such as \u003ccode\u003eistio.ingressgateway.replicaCountMin\u003c/code\u003e and \u003ccode\u003eistio.pilot.replicaCountMin\u003c/code\u003e to at least 3.\u003c/p\u003e\n"],["\u003cp\u003eWhen backing up and draining Istio nodes, errors may occur due to PodDisruptionBudget definitions, particularly with \u003ccode\u003eistio-ingressgateway\u003c/code\u003e and \u003ccode\u003eistio-pilot\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eFor other Istio components without a \u003ccode\u003ereplicaCountMin\u003c/code\u003e property, refer to the GKE documentation for manually upgrading a cluster or node pool or Istio documentation for \u003ccode\u003eIstioOperator\u003c/code\u003e options.\u003c/p\u003e\n"]]],[],null,["# Expand Istio property replica counts to avoid problems when draining Istio nodes\n\n| You are currently viewing version 1.6 of the Apigee hybrid documentation. **This version is end of life.** You should upgrade to a newer version. For more information, see [Supported versions](/apigee/docs/hybrid/supported-platforms#supported-versions).\n\n\nWhen draining Istio pods some nodes may not drain because they have a replica count of 1, while 3 or\nmore replicas are required. In order to avoid this, you should set the minimum replica count for each\nproperty to at least 3.\n\n\nWhen backing up and draining Istio nodes you may see errors like: \n\n```\nkubectl drain` failed to evict and reschedule pods to another node due to PodDisruptionBudget definitions:\n===\nNAMESPACE NAME MIN AVAILABLE MAX UNAVAILABLE ALLOWED DISRUPTIONS AGE\nistio-system istio-ingressgateway 1 N/A 2 5d11h\nistio-system istio-pilot 1 N/A 2 5d11h\n===\n```\n\n\nFor `istio-ingressgateway` and `istio-pilot` you can set the\n`istio.ingressgateway.replicaCountMin` and `istio.pilot.replicaCountMin`\nproperties to **`3`** or higher. See the\n[Configuration properties reference,\n`istio`](/apigee/docs/hybrid/v1.3/config-prop-ref#istio).\n\n\nFor other `istio` components (that don't have a replicaCountMin property), see\n[Manually\nupgrading a cluster or node pool](https://cloud.google.com/kubernetes-engine/docs/how-to/upgrading-a-cluster) in the GKE documentation or\n[IstioOperator\nOptions](https://istio.io/latest/docs/reference/config/istio.operator.v1alpha1/) in the Istio documentation."]]
