Nginxで、アクセスしたらちゃんと返ってきているのにログを見ると connect() failed (111:Connection refused) が頻発に発生している謎を調査したら、 いままで知らなかったNginxの挙動にたどり着いたのでメモ。 (ただしよく見るとドキュメントにちゃんと書いてあったというオチ) 問題 [error] 11#11: *21735 connect() failed (111: Connection refused) while connecting to upstream, client: xx.xx.x.x, server: example.com, request: "GET /hogehoge HTTP/2.0", upstream: "http://[::1]:3000/hogehoge", host: "xx.xx.x.x", referrer:
![Nginxのupstreamに安易にlocalhostと書くと嵌まる罠、またはドメイン名解決の挙動 - Qiita](https://cdn-ak-scissors.b.st-hatena.com/image/square/8a124251c7087a5e27f1d2932325224f1bd6a134/height=288;version=1;width=512/https%3A%2F%2Fqiita-user-contents.imgix.net%2Fhttps%253A%252F%252Fcdn.qiita.com%252Fassets%252Fpublic%252Farticle-ogp-background-412672c5f0600ab9a64263b751f1bc81.png%3Fixlib%3Drb-4.0.0%26w%3D1200%26mark64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-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%26mark-x%3D142%26mark-y%3D57%26blend64%3DaHR0cHM6Ly9xaWl0YS11c2VyLWNvbnRlbnRzLmltZ2l4Lm5ldC9-dGV4dD9peGxpYj1yYi00LjAuMCZoPTc2Jnc9NzcwJnR4dD0lNDB5b2tvbW90b2QmdHh0LWNvbG9yPSUyMzIxMjEyMSZ0eHQtZm9udD1IaXJhZ2lubyUyMFNhbnMlMjBXNiZ0eHQtc2l6ZT0zNiZ0eHQtYWxpZ249bGVmdCUyQ3RvcCZzPTliMzZhZGZmYjE3MGNmNTg0MzgyYjU4YTFhODNkNjlk%26blend-x%3D142%26blend-y%3D486%26blend-mode%3Dnormal%26s%3D648a80fdc41b6619ba2e3e00190cc6ff)