[[["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"]],[["わかりにくい","hardToUnderstand","thumb-down"],["情報またはサンプルコードが不正確","incorrectInformationOrSampleCode","thumb-down"],["必要な情報 / サンプルがない","missingTheInformationSamplesINeed","thumb-down"],["翻訳に関する問題","translationIssue","thumb-down"],["その他","otherDown","thumb-down"]],["最終更新日 2025-09-04 UTC。"],[],[],null,["# Switch between a target instance and a backend service\n\nThis page describes how to switch the target of a forwarding rule between a\ntarget instance and a backend service.\n\nExternal protocol forwarding\n----------------------------\n\nTo switch an external forwarding rule's target from a target instance to a\nbackend service (or the other way around), you need to delete and re-create\nthe forwarding rule with the new target. This method requires a static IP\naddress so that you can use the same address with the new forwarding rule.\n\nDeleting and re-creating the forwarding rule is the only way to switch between\nexternal protocol forwarding and a backend service-based external passthrough Network Load Balancer.\n\nInternal protocol forwarding\n----------------------------\n\nThere are two ways to switch between internal protocol forwarding and an\ninternal passthrough Network Load Balancer:\n\n- You can switch between a target instance and a backend service by updating the\n forwarding rule with the `gcloud compute forwarding-rules set-target` command\n as described in\n [Change the target of an internal forwarding rule](#int-change-target).\n When switching between\n internal protocol forwarding and an internal passthrough Network Load Balancer, you don't need\n to delete and re-create the forwarding rule. The forwarding rule continues to\n use the same internal IP address (whether static or ephemeral).\n\n- You can also switch between a target instance and a backend service by deleting\n and re-creating the forwarding rule. However, this method requires a static\n IPv4 address in order to use the same address with the new forwarding rule.\n You can't use this method for IPv6 addresses because reserving an IPv6 address\n is not supported.\n\nA target instance does not specify any protocol---it inherits the protocols and\nports of the forwarding rule. Therefore, when switching a forwarding rule to\nreference a backend service, you must ensure that the IP protocol of the\nforwarding rule (either TCP or UDP) matches the protocol of the backend\nservice (either TCP or UDP).\n\nThe following diagram shows an example that uses internal protocol forwarding.\n[](/static/load-balancing/images/pf-int-switch-target.svg) Switch between a target instance and a backend service.\n\n### Change the target of an internal forwarding rule\n\nTo change a forwarding rule from pointing to a target instance to pointing to a\nregional backend service, use the following command: \n\n```\ngcloud compute forwarding-rules set-target FORWARDING_RULE \\\n --backend-service=BACKEND_SERVICE \\\n --region=REGION\n```\n\nTo transition back to a target instance, use the following command: \n\n```\ngcloud compute forwarding-rules set-target FORWARDING_RULE \\\n --target-instance=TARGET_INSTANCE \\\n --target-instance-zone=ZONE\n```"]]
