The error was: NoInstallationError("Could not find a usable 'nginx' binary. Ensure nginx exists, the binary is executable, and your PATH is set correctly.",) の解決方法
The error was: NoInstallationError(“Could not find a usable ‘nginx’ binary. Ensure nginx exists, the binary is executable, and your PATH is set correctly.”,) というエラーが発生したときの解決方法をご紹介します。
背景 crontab で certbot-auto renew --nginx がエラー
Let’s Encrypt の SSL 証明書を certbot と crontab で自動更新する設定方法 にて設定した処理がエラーで失敗していました。
解決方法 PATH を適切に設定する
cron の実行結果のログに以下のようなエラーメッセージが出力されていました。
Saving debug log to /var/log/letsencrypt/letsencrypt.log
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Processing /etc/letsencrypt/renewal/codenote.net.conf
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Cert is due for renewal, auto-renewing...
Non-interactive renewal: random delay of 18.66088887793885 seconds
Could not choose appropriate plugin: The nginx plugin is not working; there may be problems with your existing configuration.
The error was: NoInstallationError("Could not find a usable 'nginx' binary. Ensure nginx exists, the binary is executable, and your PATH is set correctly.",)
Attempting to renew cert (codenote.net) from /etc/letsencrypt/renewal/codenote.net.conf produced an unexpected error: The nginx plugin is not working; there may be problems with your existing configuration.
The error was: NoInstallationError("Could not find a usable 'nginx' binary. Ensure nginx exists, the binary is executable, and your PATH is set correctly.",). Skipping.
All renewal attempts failed. The following certs could not be renewed:
/etc/letsencrypt/live/codenote.net/fullchain.pem (failure)
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All renewal attempts failed. The following certs could not be renewed:
/etc/letsencrypt/live/codenote.net/fullchain.pem (failure)
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1 renew failure(s), 0 parse failure(s)
The error was: NoInstallationError(“Could not find a usable ‘nginx’ binary. Ensure nginx exists, the binary is executable, and your PATH is set correctly.”,) のエラーメッセージ通り、 PATH が適切に設定されてないのが問題なので crontab の PATH を見直しましょう。
$ crontab -l
PATH=/usr/local/bin:/bin:/usr/bin
$ which nginx
/usr/sbin/nginx
という状態だったので、crontab を以下のように PATH に /usr/sbin も追加してあげれば OK です。
$ crontab -l
PATH=/usr/local/bin:/usr/sbin:/bin:/usr/bin
以上、crontab の PATH 設定漏れ問題に直面した、現場からお送りしました。