[[["わかりやすい","easyToUnderstand","thumb-up"],["問題の解決に役立った","solvedMyProblem","thumb-up"],["その他","otherUp","thumb-up"]],[["必要な情報がない","missingTheInformationINeed","thumb-down"],["複雑すぎる / 手順が多すぎる","tooComplicatedTooManySteps","thumb-down"],["最新ではない","outOfDate","thumb-down"],["翻訳に関する問題","translationIssue","thumb-down"],["サンプル / コードに問題がある","samplesCodeIssue","thumb-down"],["その他","otherDown","thumb-down"]],["最終更新日 2025-08-19 UTC。"],[[["\u003cp\u003eA regional managed instance group (MIG) is considered unbalanced when the difference in virtual machines (VMs) between two zones is two or more.\u003c/p\u003e\n"],["\u003cp\u003eManually rebalancing an unbalanced MIG involves deleting VMs from zones with more instances or resizing the group to add instances to zones with fewer VMs.\u003c/p\u003e\n"],["\u003cp\u003eEven with proactive instance redistribution turned off, resizing a MIG will cause it to opportunistically converge toward balance by adding VMs to zones with the fewest or removing them from the zones with the most.\u003c/p\u003e\n"],["\u003cp\u003eRe-enabling proactive redistribution requires an initial manual rebalancing of the MIG to ensure an even distribution of instances across zones.\u003c/p\u003e\n"]]],[],null,["*** ** * ** ***\n\nA\n[regional managed instance group (MIG)](/compute/docs/instance-groups#managed_instance_groups)\nis not balanced if the difference in the number of VMs between\ntwo zones is 2 or more VMs. A regional MIG can fall out of balance if you\ndisable\n[proactive instance redistribution](/compute/docs/instance-groups/regional-migs#proactive_instance_redistribution)\nand then delete or abandon instances to cause an uneven distribution across\nzones.\n\nIf your group is not balanced and you want to re-enable proactive instance\ndistribution, you must first manually rebalance your group to achieve an even\ndistribution of instances across zones.\n\nManually rebalance by deleting VMs or resizing the group\n\nYou can manually rebalance your group to achieve an even distribution of\ninstances across zones by\n[deleting](/compute/docs/instance-groups/add-remove-vms-in-mig#delete_from_group)\nVMs from zones with more instances or by\n[resizing](/compute/docs/instance-groups/add-remove-vms-in-mig#resize_managed_group)\nto add instances to zones with fewer VMs until the distribution is even.\n\nWhen you resize a MIG that has proactive instance redistribution turned off,\nthe group still *opportunistically* converges toward balance, treating each\nresize operation as an opportunity to balance the group:\n\n- When the group grows, the group always tries to add VMs to the zones with the smallest number of VMs.\n- When the group shrinks, the group always removes VMs from the zones with the largest number of VMs.\n\n[](/static/compute/images/rmig-manual-redistribution.svg) *Example of manually resizing a group to achieve even redistribution*\n\nWhat's next\n\n- Learn how to re-enable or disable [proactive redistribution](/compute/docs/instance-groups/regional-mig-enable-disable-proactive-redistribution).\n- Learn how to set a regional MIG's [target distribution shape](/compute/docs/instance-groups/regional-mig-set-target-distribution-shape)."]]