正在阅读下面文章的是一个七岁的孩子，你该如何表达才能让他理解以下技术内容？（费曼学习法）
你这篇文章要解决的最重要问题是什么？
记录自己的配置过程。参考文章：Setting up a Cloudflare Tunnel on the Raspberry Pi - Pi My Life Up
树莓派3b闲了很长时间，想把它利用起来。重装了 Ubuntu 22.04 LTS。
所有依次执行的命令：
sudo apt update
sudo apt upgrade
sudo apt install curl lsb-release
curl -L https://pkg.cloudflare.com/cloudflare-main.gpg | sudo tee /usr/share/keyrings/cloudflare-archive-keyring.gpg >/dev/null
echo "deb [signed-by=/usr/share/keyrings/cloudflare-archive-keyring.gpg] https://pkg.cloudflare.com/cloudflared $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/cloudflared.list
sudo apt update
sudo apt install cloudflared
cloudflared tunnel login # 点击出现的链接，选择域名
cloudflared tunnel create TUNNELNAME
cloudflared tunnel route dns TUNNELNAME DOMAINNAME
cloudflared tunnel run --url localhost:PORT TUNNELNAME设置 systemd 服务，使得开机自启：
sudo vim ~/.cloudflared/config.yml
sudo cloudflared --config ~/.cloudflared/config.yml service install
sudo systemctl enable cloudflared
sudo systemctl start cloudflared~/.cloudflared/config.yml:
tunnel: [TUNNELNAME]
credentials-file: /home/[USERNAME]/.cloudflared/[UUID].json
ingress:
- hostname: [HOSTNAME]
service: [PROTOCOL]://localhost:[PORT]
- service: http_status:404