SSH 키 기반 로그인

키 생성·배포

ssh-keygen -t rsa          # passphrase 비우면 자동 로그인용
ssh-copy-id user@host
# 또는 수동
scp ~/.ssh/id_rsa.pub user@host:
ssh user@host
mkdir -p ~/.ssh && chmod 700 ~/.ssh
cat id_rsa.pub >> ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys

서버 설정

# /etc/ssh/sshd_config
PubkeyAuthentication yes
AuthorizedKeysFile .ssh/authorized_keys
systemctl restart sshd   # 또는 service sshd restart

호스트별 키 (~/.ssh/config)

Host myserver
  HostName example.com
  User myuser
  IdentityFile ~/.ssh/id_rsa_myserver

다수 호스트 (hosts + copy-id)

# /etc/hosts
# 192.168.0.100 server_1
ssh-copy-id -i ~/.ssh/id_rsa.pub user1@server_2

디버그: ssh -vvv user@host