[Docker] Error response from daemon: Get "https://registry-1.docker.io/v2/": x509: certificate signed by unknown authority

문제 발생

• 갑자기 docker hub에서 image pull이 안 된다.

rapa@manager:~$ docker pull influxdb
Using default tag: latest
Error response from daemon: Get "https://registry-1.docker.io/v2/": x509: certificate signed by unknown authority

Error response from daemon: Get "https://registry-1.docker.io/v2/": x509: certificate signed by unknown authority

• 다른 VM 머신에서는 image pull이 잘 된다.

rapa@worker1:~$ docker pull influxdb
Using default tag: latest
latest: Pulling from library/influxdb
76dff75df4d9: Pull complete 
3e8c90a1c4bb: Pull complete 
b3662c105080: Pull complete 
709a9b6ea5e8: Pull complete 
b43f10f9a393: Pull complete 
73525c4cb21f: Pull complete 
6a94442e11ba: Pull complete 
bf874bbac1af: Pull complete 
5e9974947659: Pull complete 
5c566ee67edc: Pull complete 
Digest: sha256:251ce6c49c44fcfb6145192c6d5779a7bd37c384d6e32ce31b9d5f41e9d56867
Status: Downloaded newer image for influxdb:latest
docker.io/library/influxdb:latest

삽질 1) 서비스 재실행

rapa@manager:~$ sudo systemctl daemon-reload 
rapa@manager:~$ sudo systemctl restart docker 

rapa@manager:~$ docker pull influxdb
Using default tag: latest
Error response from daemon: Get "https://registry-1.docker.io/v2/": x509: certificate signed by unknown authority

daemon-reload와 docker를 재실행해도 해결이 안 된다.

삽질 2) 도커 재로그인

로그인 자체가 안 되고, 동일한 오류 메세지가 나온다.

해결

• ca-certificates 패키지 설치

rapa@manager:~$ sudo apt install ca-certificates

• ca-certificates 업데이트

rapa@manager:~$ sudo update-ca-certificates
Updating certificates in /etc/ssl/certs...
0 added, 0 removed; done.
Running hooks in /etc/ca-certificates/update.d...
done.

• 도커 서비스 재실행

rapa@manager:~$ sudo systemctl restart docker

• 성공

rapa@manager:~$ docker pull influxdb
Using default tag: latest
latest: Pulling from library/influxdb
76dff75df4d9: Pull complete 
3e8c90a1c4bb: Pull complete 
b3662c105080: Pull complete 
709a9b6ea5e8: Pull complete 
b43f10f9a393: Pull complete 
73525c4cb21f: Pull complete 
6a94442e11ba: Pull complete 
bf874bbac1af: Pull complete 
5e9974947659: Pull complete 
5c566ee67edc: Pull complete 
Digest: sha256:251ce6c49c44fcfb6145192c6d5779a7bd37c384d6e32ce31b9d5f41e9d56867
Status: Downloaded newer image for influxdb:latest
docker.io/library/influxdb:latest