I can log in successfully to my cloud instance as user 'ubuntu' via SSH but cannot log in as user 'root'. There are several posts extant concerned with altering the ssh config in order to allow root access although none have worked from me. For example, I have made the usual changes to the /etc/ssh/sshd_config file, namely:
#Authentication PermitRootLogin yes
This had no effect.
Now, the message I get when I try to log in as 'root' is:
Please login as the user "ubuntu" rather than the user "root".
Grepping for "Please login", I found in the '/usr/lib/python3/dist-packages/cloudinit/config/cc_ssh.py' file (of all places), the following lines:
DISABLE_ROOT_OPTS = ( "no-port-forwarding,no-agent-forwarding," "no-X11-forwarding,command=\"echo \'Please login as the user \\\"$USER\\\"" " rather than the user \\\"root\\\".\';echo;sleep 10\"")
I can't make much of this. I'm guessing that this Python script was run when the instance was first created and is responsible for some additional SSH settings somewhere that are blocking me from logging in as 'root'.
It seems to me that the offending ssh configuration directives are 'no-X11-forwarding' and the other two. I've come to this conclusion since they seem to be associated with the offending message.
I'm guessing that the
command directive instructs the ssh daemon to show this message when the associated directives are violated. Am I on the right track?
One thing I should add to this is that I am aware of the arguments against logging in as root user. However, this is a private instance and I will be the only user. I need ssh access as 'root' because the deployment scripts I have need to run as root in order to avoid complications.
Update: The python script mentioned below is part of the Ubuntu CloudInit package.
Further update: Here are the contents of the /etc/pam.d/sshd file...
# PAM configuration for the Secure Shell service # Standard Un*x authentication. @include common-auth # Disallow non-root logins when /etc/nologin exists. account required pam_nologin.so # Uncomment and edit /etc/security/access.conf if you need to set complex # access limits that are hard to express in sshd_config. # account required pam_access.so # Standard Un*x authorization. @include common-account # SELinux needs to be the first session rule. This ensures that any # lingering context has been cleared. Without this it is possible that a # module could execute code in the wrong domain. session [success=ok ignore=ignore module_unknown=ignore default=bad] pam_selinux.so close # Set the loginuid process attribute. session required pam_loginuid.so # Create a new session keyring. session optional pam_keyinit.so force revoke # Standard Un*x session setup and teardown. @include common-session # Print the message of the day upon successful login. # This includes a dynamically generated part from /run/motd.dynamic # and a static (admin-editable) part from /etc/motd. session optional pam_motd.so motd=/run/motd.dynamic session optional pam_motd.so noupdate # Print the status of the user's mailbox upon successful login. session optional pam_mail.so standard noenv #  # Set up user limits from /etc/security/limits.conf. session required pam_limits.so # Read environment variables from /etc/environment and # /etc/security/pam_env.conf. session required pam_env.so #  # In Debian 4.0 (etch), locale-related environment variables were moved to # /etc/default/locale, so read that as well. session required pam_env.so user_readenv=1 envfile=/etc/default/locale # SELinux needs to intervene at login time to ensure that the process starts # in the proper default security context. Only sessions which are intended # to run in the user's context should be run after this. session [success=ok ignore=ignore module_unknown=ignore default=bad] pam_selinux.so open # Standard Un*x password updating. @include common-password
...and the contents of the /etc/ssh/sshd_config file...
# Package generated configuration file # See the sshd_config(5) manpage for details # What ports, IPs and protocols we listen for Port 22 # Use these options to restrict which interfaces/protocols sshd will bind to #ListenAddress :: #ListenAddress 0.0.0.0 Protocol 2 # HostKeys for protocol version 2 HostKey /etc/ssh/ssh_host_rsa_key HostKey /etc/ssh/ssh_host_dsa_key HostKey /etc/ssh/ssh_host_ecdsa_key HostKey /etc/ssh/ssh_host_ed25519_key #Privilege Separation is turned on for security UsePrivilegeSeparation yes # Lifetime and size of ephemeral version 1 server key KeyRegenerationInterval 3600 ServerKeyBits 1024 # Logging SyslogFacility AUTH LogLevel INFO # Authentication: LoginGraceTime 120 PermitRootLogin yes StrictModes yes RSAAuthentication yes PubkeyAuthentication yes #AuthorizedKeysFile %h/.ssh/authorized_keys # Don't read the user's ~/.rhosts and ~/.shosts files IgnoreRhosts yes # For this to work you will also need host keys in /etc/ssh_known_hosts RhostsRSAAuthentication no # similar for protocol version 2 HostbasedAuthentication no # Uncomment if you don't trust ~/.ssh/known_hosts for RhostsRSAAuthentication #IgnoreUserKnownHosts yes # To enable empty passwords, change to yes (NOT RECOMMENDED) PermitEmptyPasswords no # Change to yes to enable challenge-response passwords (beware issues with # some PAM modules and threads) ChallengeResponseAuthentication yes # Change to no to disable tunnelled clear text passwords PasswordAuthentication yes # Kerberos options #KerberosAuthentication no #KerberosGetAFSToken no #KerberosOrLocalPasswd yes #KerberosTicketCleanup yes # GSSAPI options #GSSAPIAuthentication no #GSSAPICleanupCredentials yes X11Forwarding yes X11DisplayOffset 10 PrintMotd no PrintLastLog yes TCPKeepAlive yes #UseLogin no #MaxStartups 10:30:60 #Banner /etc/issue.net # Allow client to pass locale environment variables AcceptEnv LANG LC_* Subsystem sftp /usr/lib/openssh/sftp-server # Set this to 'yes' to enable PAM authentication, account processing, # and session processing. If this is enabled, PAM authentication will # be allowed through the ChallengeResponseAuthentication and # PasswordAuthentication. Depending on your PAM configuration, # PAM authentication via ChallengeResponseAuthentication may bypass # the setting of "PermitRootLogin without-password". # If you just want the PAM account and session checks to run without # PAM authentication, then enable this but set PasswordAuthentication # and ChallengeResponseAuthentication to 'no'. UsePAM yes