ROS2 apt update key 문제.

$ sudo apt clean && sudo apt update
받기:1 https://dl.yarnpkg.com/debian stable InRelease [17.1 kB]
기존:2 http://packages.osrfoundation.org/gazebo/ubuntu-stable focal InRelease                                             
기존:3 http://dl.google.com/linux/chrome/deb stable InRelease                                                             
받기:4 http://packages.ros.org/ros2/ubuntu focal InRelease [4,670 B]                                                      
기존:6 http://packages.microsoft.com/repos/edge stable InRelease                                                          
무시:7 http://linux.dropbox.com/ubuntu disco InRelease                                                                    
기존:8 http://packages.microsoft.com/repos/code stable InRelease                                                          
오류:4 http://packages.ros.org/ros2/ubuntu focal InRelease                                                                
  다음 서명들은 공개키가 없기 때문에 인증할 수 없습니다: NO_PUBKEY F42ED6FBAB17C654
받기:9 http://linux.dropbox.com/ubuntu disco Release [6,598 B]                                                            
기존:11 http://kr.archive.ubuntu.com/ubuntu focal InRelease                                                               
기존:12 http://security.ubuntu.com/ubuntu focal-security InRelease                                                        
기존:13 http://kr.archive.ubuntu.com/ubuntu focal-updates InRelease                                                       
무시:5 https://www.scootersoftware.com bcompare4 InRelease                                               
기존:14 http://kr.archive.ubuntu.com/ubuntu focal-backports InRelease         
기존:15 https://www.scootersoftware.com bcompare4 Release
내려받기 28.4 k바이트, 소요시간 1초 (20.4 k바이트/초)
패키지 목록을 읽는 중입니다... 완료
의존성 트리를 만드는 중입니다       
상태 정보를 읽는 중입니다... 완료
패키지 525이(가) 업그레이드되었습니다. 'apt list --upgradable'를 실행하여 확인해 보십시오.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://packages.ros.org/ros2/ubuntu focal InRelease: 다음 서명들은 공개키가 없기 때문에 인증할 수 없습니다: NO_PUBKEY F42ED6FBAB17C654
W: http://packages.ros.org/ros2/ubuntu/dists/focal/InRelease 파일을 받는데 실패했습니다  다음 서명들은 공개키가 없기 때문에 인증할 수 없습니다: NO_PUBKEY F42ED6FBAB17C654
W: Some index files failed to download. They have been ignored, or old ones used instead.

 

이런 문제가 발생할 때가 있다.

 

$ apt-key list

로 현재 설치된 키를 확인 할 수 있다.

 

ROS2 키를 확인한다.

$ curl http://repo.ros2.org/repos.key | gpg --with-fingerprint

 

안되는 키를 삭제한다.

$ sudo apt-key del F42ED6FBAB17C654

 

새 키를 추가한다.

$ curl http://repo.ros2.org/repos.key | sudo apt-key add -
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  1678  100  1678    0     0   5707      0 --:--:-- --:--:-- --:--:--  5707
OK