SSH节点互信配置

#1. Generate a pair of authentication keys on the host:
ssh-keygen -t rsa
#2. Enter an empty passphrase by pressing the Enter key when asked for the passphrase, and use the default file name. 不必输入，直接Enter
#3. Add the public key to the authorized keys: 不必输入，直接Enter
touch ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys
cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys

注：首次切换节点需要输入yes，之后不再需要（If necessary, answer the question about the RSA key fingerprint with yes）