ROS2安装：Failed to connect to raw.githubusercontent.com port 443 after 3 ms: Connection refused

前言

这两天换了台电脑装ROS2，按照官网的教程进行安装，发现到如下两步会出现问题，最后把解决的过程记录，便于自己理解

环境

Ubuntu 22.04
ROS2 humble(需要安装)
已经科学上网

流程

按照官网的步骤如下：

官网: https://docs.ros.org/en/humble/Installation/Ubuntu-Install-Debians.html#

Set locale

locale  # check for UTF-8

sudo apt update && sudo apt install locales
sudo locale-gen en_US en_US.UTF-8
sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
export LANG=en_US.UTF-8

locale  # verify settings

Add the ROS2 apt repository

First ensure that the Ubuntu Universe repository is enabled.

sudo apt install software-properties-common
sudo add-apt-repository universe

Now add the ROS 2 GPG key with apt.

sudo apt update && sudo apt install curl
sudo curl -sSL https://raw.githubusercontent.com/ros/rosdistro/master/ros.key -o /usr/share/keyrings/ros-archive-keyring.gpg

Then add the repository to your sources list.

echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/ros-archive-keyring.gpg] http://packages.ros.org/ros2/ubuntu $(. /etc/os-release && echo $UBUNTU_CODENAME) main" | sudo tee /etc/apt/sources.list.d/ros2.list > /dev/null

Install ROS2 bag

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sudo apt update
sudo apt upgrade

之后就可以使用sudo apt install来下载需要的ROS2的包了

sudo apt install ros-humble-desktop
sudo apt install ros-humble-ros-base
sudo apt install ros-dev-tools

问题

在正常的安装流程的这一步sudo add-apt-repository universe会出现以下问题

Adding component(s) 'universe' to all repositories.
Press [ENTER] to continue or Ctrl-c to cancel.
Hit:1 http://archive.ubuntu.com/ubuntu jammy InRelease
Hit:2 http://archive.ubuntu.com/ubuntu jammy-updates InRelease
Hit:3 http://archive.ubuntu.com/ubuntu jammy-backports InRelease
Get:4 http://packages.ros.org/ros2/ubuntu jammy InRelease [4,673 B]
Err:4 http://packages.ros.org/ros2/ubuntu jammy InRelease  
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654
Hit:5 http://archive.ubuntu.com/ubuntu jammy-security InRelease
Reading package lists... Done
W: GPG error: http://packages.ros.org/ros2/ubuntu jammy InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654
E: The repository 'http://packages.ros.org/ros2/ubuntu jammy InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

使用搜到的增加PUBKEY的方法无法解决，并且如果在后面，需要增加ros的key时候，会出现连接拒绝的情况

sudo curl -sSL https://raw.githubusercontent.com/ros/rosdistro/master/ros.key -o /usr/share/keyrings/ros-archive-keyring.gpg
curl: (7) Failed to connect to raw.githubusercontent.com port 443 after 3 ms: Connection refused

解决

1. sudo vim etc/hosts
2. 添加一行：185.199.108.133 raw.githubusercontent.com
3. :wq保存退出