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#!/usr/bin/python |
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# |
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|
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# Copyright (C) 2010 Google Inc. |
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# |
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# This program is free software; you can redistribute it and/or modify |
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# it under the terms of the GNU General Public License as published by |
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# the Free Software Foundation; either version 2 of the License, or |
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# (at your option) any later version. |
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# |
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# This program is distributed in the hope that it will be useful, but |
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# WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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# General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with this program; if not, write to the Free Software |
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
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# 02110-1301, USA. |
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|
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"""Tool to setup the SSH configuration on a remote node. |
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|
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This is needed before we can join the node into the cluster. |
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|
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""" |
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|
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# pylint: disable=C0103 |
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# C0103: Invalid name setup-ssh |
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|
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import getpass |
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import logging |
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import paramiko |
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import os.path |
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import optparse |
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import sys |
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|
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from ganeti import cli |
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from ganeti import constants |
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from ganeti import errors |
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from ganeti import netutils |
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from ganeti import ssconf |
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from ganeti import ssh |
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from ganeti import utils |
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|
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|
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class RemoteCommandError(errors.GenericError): |
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"""Exception if remote command was not successful. |
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|
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""" |
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|
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|
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class JoinCheckError(errors.GenericError): |
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"""Exception raised if join check fails. |
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|
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""" |
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|
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|
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class HostKeyVerificationError(errors.GenericError): |
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"""Exception if host key do not match. |
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|
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""" |
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|
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|
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class AuthError(errors.GenericError): |
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"""Exception for authentication errors to hosts. |
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|
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""" |
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|
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|
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def _CheckJoin(transport): |
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"""Checks if a join is safe or dangerous. |
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|
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Note: This function relies on the fact, that all |
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hosts have the same configuration at compile time of |
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Ganeti. So that the constants do not mismatch. |
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|
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@param transport: The paramiko transport instance |
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@return: True if the join is safe; False otherwise |
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|
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""" |
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sftp = transport.open_sftp_client() |
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ss = ssconf.SimpleStore() |
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ss_cluster_name_path = ss.KeyToFilename(constants.SS_CLUSTER_NAME) |
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|
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cluster_files = [ |
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(constants.NODED_CERT_FILE, utils.ReadFile(constants.NODED_CERT_FILE)), |
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(ss_cluster_name_path, utils.ReadFile(ss_cluster_name_path)), |
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] |
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|
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for (filename, local_content) in cluster_files: |
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try: |
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remote_content = _ReadSftpFile(sftp, filename) |
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except IOError, err: |
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# Assume file does not exist. Paramiko's error reporting is lacking. |
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logging.debug("Failed to read %s: %s", filename, err) |
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continue |
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|
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if remote_content != local_content: |
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logging.error("File %s doesn't match local version", filename) |
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return False |
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|
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return True |
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|
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|
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def _RunRemoteCommand(transport, command): |
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"""Invokes and wait for the command over SSH. |
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|
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@param transport: The paramiko transport instance |
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@param command: The command to be executed |
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|
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""" |
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chan = transport.open_session() |
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chan.set_combine_stderr(True) |
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output_handler = chan.makefile("r") |
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chan.exec_command(command) |
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|
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result = chan.recv_exit_status() |
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msg = output_handler.read() |
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|
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out_msg = "'%s' exited with status code %s, output %r" % (command, result, |
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msg) |
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|
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# If result is -1 (no exit status provided) we assume it was not successful |
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if result: |
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raise RemoteCommandError(out_msg) |
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|
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if msg: |
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logging.info(out_msg) |
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|
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|
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def _InvokeDaemonUtil(transport, command): |
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"""Invokes daemon-util on the remote side. |
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|
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@param transport: The paramiko transport instance |
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@param command: The daemon-util command to be run |
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|
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""" |
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_RunRemoteCommand(transport, "%s %s" % (constants.DAEMON_UTIL, command)) |
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|
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|
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def _ReadSftpFile(sftp, filename): |
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"""Reads a file over sftp. |
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|
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@param sftp: An open paramiko SFTP client |
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@param filename: The filename of the file to read |
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@return: The content of the file |
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|
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""" |
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remote_file = sftp.open(filename, "r") |
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try: |
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return remote_file.read() |
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finally: |
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remote_file.close() |
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|
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|
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def _WriteSftpFile(sftp, name, perm, data): |
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"""SFTPs data to a remote file. |
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|
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@param sftp: A open paramiko SFTP client |
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@param name: The remote file name |
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@param perm: The remote file permission |
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@param data: The data to write |
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|
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""" |
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remote_file = sftp.open(name, "w") |
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try: |
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sftp.chmod(name, perm) |
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remote_file.write(data) |
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finally: |
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remote_file.close() |
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|
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|
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def SetupSSH(transport): |
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"""Sets the SSH up on the other side. |
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|
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@param transport: The paramiko transport instance |
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|
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""" |
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priv_key, pub_key, auth_keys = ssh.GetUserFiles(constants.GANETI_RUNAS) |
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keyfiles = [ |
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(constants.SSH_HOST_DSA_PRIV, 0600), |
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(constants.SSH_HOST_DSA_PUB, 0644), |
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(constants.SSH_HOST_RSA_PRIV, 0600), |
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(constants.SSH_HOST_RSA_PUB, 0644), |
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(priv_key, 0600), |
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(pub_key, 0644), |
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] |
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|
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sftp = transport.open_sftp_client() |
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|
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filemap = dict((name, (utils.ReadFile(name), perm)) |
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for (name, perm) in keyfiles) |
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|
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auth_path = os.path.dirname(auth_keys) |
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|
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try: |
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sftp.mkdir(auth_path, 0700) |
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except IOError, err: |
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# Sadly paramiko doesn't provide errno or similiar |
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# so we can just assume that the path already exists |
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logging.info("Assuming directory %s on remote node exists: %s", |
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auth_path, err) |
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|
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for name, (data, perm) in filemap.iteritems(): |
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_WriteSftpFile(sftp, name, perm, data) |
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|
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authorized_keys = sftp.open(auth_keys, "a+") |
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try: |
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# Due to the way SFTPFile and BufferedFile are implemented, |
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# opening in a+ mode and then issuing a read(), readline() or |
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# iterating over the file (which uses read() internally) will see |
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# an empty file, since the paramiko internal file position and the |
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# OS-level file-position are desynchronized; therefore, we issue |
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# an explicit seek to resynchronize these; writes should (note |
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# should) still go to the right place |
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authorized_keys.seek(0, 0) |
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# We don't have to close, as the close happened already in AddAuthorizedKey |
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utils.AddAuthorizedKey(authorized_keys, filemap[pub_key][0]) |
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finally: |
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authorized_keys.close() |
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|
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_InvokeDaemonUtil(transport, "reload-ssh-keys") |
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|
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|
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def ParseOptions(): |
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"""Parses options passed to program. |
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|
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""" |
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program = os.path.basename(sys.argv[0]) |
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|
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parser = optparse.OptionParser(usage=("%prog [--debug|--verbose] [--force]" |
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" <node> <node...>"), prog=program) |
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parser.add_option(cli.DEBUG_OPT) |
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parser.add_option(cli.VERBOSE_OPT) |
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parser.add_option(cli.NOSSH_KEYCHECK_OPT) |
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default_key = ssh.GetUserFiles(constants.GANETI_RUNAS)[0] |
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parser.add_option(optparse.Option("-f", dest="private_key", |
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default=default_key, |
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help="The private key to (try to) use for" |
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"authentication ")) |
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parser.add_option(optparse.Option("--key-type", dest="key_type", |
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choices=("rsa", "dsa"), default="dsa", |
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help="The private key type (rsa or dsa)")) |
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parser.add_option(optparse.Option("-j", "--force-join", dest="force_join", |
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action="store_true", default=False, |
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help="Force the join of the host")) |
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|
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(options, args) = parser.parse_args() |
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|
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return (options, args) |
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|
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|
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def SetupLogging(options): |
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"""Sets up the logging. |
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|
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@param options: Parsed options |
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|
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""" |
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fmt = "%(asctime)s: %(threadName)s " |
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if options.debug or options.verbose: |
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fmt += "%(levelname)s " |
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fmt += "%(message)s" |
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|
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formatter = logging.Formatter(fmt) |
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|
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file_handler = logging.FileHandler(constants.LOG_SETUP_SSH) |
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stderr_handler = logging.StreamHandler() |
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stderr_handler.setFormatter(formatter) |
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file_handler.setFormatter(formatter) |
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file_handler.setLevel(logging.INFO) |
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|
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if options.debug: |
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stderr_handler.setLevel(logging.DEBUG) |
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elif options.verbose: |
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stderr_handler.setLevel(logging.INFO) |
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else: |
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stderr_handler.setLevel(logging.WARNING) |
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|
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root_logger = logging.getLogger("") |
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root_logger.setLevel(logging.NOTSET) |
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root_logger.addHandler(stderr_handler) |
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root_logger.addHandler(file_handler) |
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|
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# This is the paramiko logger instance |
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paramiko_logger = logging.getLogger("paramiko") |
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paramiko_logger.addHandler(file_handler) |
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# We don't want to debug Paramiko, so filter anything below warning |
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paramiko_logger.setLevel(logging.WARNING) |
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|
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|
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def LoadPrivateKeys(options): |
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"""Load the list of available private keys. |
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|
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It loads the standard ssh key from disk and then tries to connect to |
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the ssh agent too. |
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|
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@rtype: list |
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@return: a list of C{paramiko.PKey} |
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|
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""" |
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if options.key_type == "rsa": |
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pkclass = paramiko.RSAKey |
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elif options.key_type == "dsa": |
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pkclass = paramiko.DSSKey |
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else: |
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logging.critical("Unknown key type %s selected (choose either rsa or dsa)", |
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options.key_type) |
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sys.exit(1) |
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|
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try: |
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private_key = pkclass.from_private_key_file(options.private_key) |
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except (paramiko.SSHException, EnvironmentError), err: |
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logging.critical("Can't load private key %s: %s", options.private_key, err) |
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sys.exit(1) |
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|
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try: |
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agent = paramiko.Agent() |
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agent_keys = agent.get_keys() |
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except paramiko.SSHException, err: |
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# this will only be seen when the agent is broken/uses invalid |
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# protocol; for non-existing agent, get_keys() will just return an |
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# empty tuple |
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logging.warning("Can't connect to the ssh agent: %s; skipping its use", |
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err) |
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agent_keys = [] |
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|
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return [private_key] + list(agent_keys) |
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|
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|
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def _FormatFingerprint(fpr): |
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"""Formats a paramiko.PKey.get_fingerprint() human readable. |
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|
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@param fpr: The fingerprint to be formatted |
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@return: A human readable fingerprint |
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|
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""" |
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return ssh.FormatParamikoFingerprint(paramiko.util.hexify(fpr)) |
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|
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|
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def LoginViaKeys(transport, username, keys): |
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"""Try to login on the given transport via a list of keys. |
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|
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@param transport: the transport to use |
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@param username: the username to login as |
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@type keys: list |
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@param keys: list of C{paramiko.PKey} to use for authentication |
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@rtype: boolean |
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@return: True or False depending on whether the login was |
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successfull or not |
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|
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""" |
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for private_key in keys: |
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try: |
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transport.auth_publickey(username, private_key) |
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fpr = _FormatFingerprint(private_key.get_fingerprint()) |
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if isinstance(private_key, paramiko.AgentKey): |
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logging.debug("Authentication via the ssh-agent key %s", fpr) |
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else: |
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logging.debug("Authenticated via public key %s", fpr) |
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return True |
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except paramiko.SSHException: |
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continue |
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else: |
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# all keys exhausted |
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return False |
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|
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|
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def LoadKnownHosts(): |
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"""Load the known hosts. |
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|
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@return: paramiko.util.load_host_keys dict |
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|
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""" |
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homedir = utils.GetHomeDir(constants.GANETI_RUNAS) |
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known_hosts = os.path.join(homedir, ".ssh", "known_hosts") |
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|
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try: |
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return paramiko.util.load_host_keys(known_hosts) |
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except EnvironmentError: |
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# We didn't find the path, silently ignore and return an empty dict |
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return {} |
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|
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|
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def _VerifyServerKey(transport, host, host_keys): |
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"""Verify the server keys. |
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|
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@param transport: A paramiko.transport instance |
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@param host: Name of the host we verify |
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@param host_keys: Loaded host keys |
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@raises HostkeyVerificationError: When the host identify couldn't be verified |
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|
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""" |
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|
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server_key = transport.get_remote_server_key() |
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keytype = server_key.get_name() |
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|
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our_server_key = host_keys.get(host, {}).get(keytype, None) |
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if not our_server_key: |
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hexified_key = _FormatFingerprint(server_key.get_fingerprint()) |
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msg = ("Unable to verify hostkey of host %s: %s. Do you want to accept" |
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" it?" % (host, hexified_key)) |
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|
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if cli.AskUser(msg): |
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our_server_key = server_key |
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|
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if our_server_key != server_key: |
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raise HostKeyVerificationError("Unable to verify host identity") |
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|
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|
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def main(): |
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"""Main routine. |
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|
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""" |
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(options, args) = ParseOptions() |
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|
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SetupLogging(options) |
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|
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all_keys = LoadPrivateKeys(options) |
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|
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passwd = None |
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username = constants.GANETI_RUNAS |
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ssh_port = netutils.GetDaemonPort("ssh") |
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host_keys = LoadKnownHosts() |
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|
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# Below, we need to join() the transport objects, as otherwise the |
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# following happens: |
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# - the main thread finishes |
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# - the atexit functions run (in the main thread), and cause the |
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# logging file to be closed |
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# - a tiny bit later, the transport thread is finally ending, and |
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# wants to log one more message, which fails as the file is closed |
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# now |
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|
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success = True |
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|
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for host in args: |
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logging.info("Configuring %s", host) |
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|
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transport = paramiko.Transport((host, ssh_port)) |
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try: |
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try: |
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transport.start_client() |
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|
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if options.ssh_key_check: |
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_VerifyServerKey(transport, host, host_keys) |
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|
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try: |
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if LoginViaKeys(transport, username, all_keys): |
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logging.info("Authenticated to %s via public key", host) |
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else: |
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if all_keys: |
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logging.warning("Authentication to %s via public key failed," |
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" trying password", host) |
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if passwd is None: |
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passwd = getpass.getpass(prompt="%s password:" % username) |
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transport.auth_password(username=username, password=passwd) |
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logging.info("Authenticated to %s via password", host) |
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except paramiko.SSHException, err: |
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raise AuthError("Auth error TODO" % err) |
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|
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if not _CheckJoin(transport): |
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if not options.force_join: |
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raise JoinCheckError(("Host %s failed join check; Please verify" |
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" that the host was not previously joined" |
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" to another cluster and use --force-join" |
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" to continue") % host) |
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|
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logging.warning("Host %s failed join check, forced to continue", |
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host) |
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|
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SetupSSH(transport) |
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logging.info("%s successfully configured", host) |
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finally: |
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transport.close() |
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# this is needed for compatibility with older Paramiko or Python |
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# versions |
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transport.join() |
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except AuthError, err: |
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logging.error("Authentication error: %s", err) |
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success = False |
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break |
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except HostKeyVerificationError, err: |
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logging.error("Host key verification error: %s", err) |
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success = False |
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except Exception, err: |
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logging.exception("During setup of %s: %s", host, err) |
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success = False |
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|
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if success: |
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sys.exit(constants.EXIT_SUCCESS) |
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|
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sys.exit(constants.EXIT_FAILURE) |
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|
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|
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if __name__ == "__main__": |
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main() |