4 # Copyright (C) 2006, 2007 Google Inc.
6 # This program is free software; you can redistribute it and/or modify
7 # it under the terms of the GNU General Public License as published by
8 # the Free Software Foundation; either version 2 of the License, or
9 # (at your option) any later version.
11 # This program is distributed in the hope that it will be useful, but
12 # WITHOUT ANY WARRANTY; without even the implied warranty of
13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 # General Public License for more details.
16 # You should have received a copy of the GNU General Public License
17 # along with this program; if not, write to the Free Software
18 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
22 """Module encapsulating ssh functionality.
30 from ganeti import utils
31 from ganeti import errors
32 from ganeti import constants
35 def GetUserFiles(user, mkdir=False):
36 """Return the paths of a user's ssh files.
38 The function will return a triplet (priv_key_path, pub_key_path,
39 auth_key_path) that are used for ssh authentication. Currently, the
40 keys used are DSA keys, so this function will return:
41 (~user/.ssh/id_dsa, ~user/.ssh/id_dsa.pub,
42 ~user/.ssh/authorized_keys).
44 If the optional parameter mkdir is True, the ssh directory will be
45 created if it doesn't exist.
47 Regardless of the mkdir parameters, the script will raise an error
48 if ~user/.ssh is not a directory.
51 user_dir = utils.GetHomeDir(user)
53 raise errors.OpExecError("Cannot resolve home of user %s" % user)
55 ssh_dir = os.path.join(user_dir, ".ssh")
56 if not os.path.lexists(ssh_dir):
59 os.mkdir(ssh_dir, 0700)
60 except EnvironmentError, err:
61 raise errors.OpExecError("Can't create .ssh dir for user %s: %s" %
63 elif not os.path.isdir(ssh_dir):
64 raise errors.OpExecError("path ~%s/.ssh is not a directory" % user)
66 return [os.path.join(ssh_dir, base)
67 for base in ["id_dsa", "id_dsa.pub", "authorized_keys"]]
71 """Wrapper for SSH commands.
74 def __init__(self, cluster_name):
75 self.cluster_name = cluster_name
77 def _BuildSshOptions(self, batch, ask_key, use_cluster_key,
79 """Builds a list with needed SSH options.
81 @param batch: same as ssh's batch option
82 @param ask_key: allows ssh to ask for key confirmation; this
83 parameter conflicts with the batch one
84 @param use_cluster_key: if True, use the cluster name as the
86 @param strict_host_check: this makes the host key checking strict
89 @return: the list of options ready to use in L{utils.RunCmd}
94 "-oHashKnownHosts=no",
95 "-oGlobalKnownHostsFile=%s" % constants.SSH_KNOWN_HOSTS_FILE,
96 "-oUserKnownHostsFile=/dev/null",
100 options.append("-oHostKeyAlias=%s" % self.cluster_name)
102 # TODO: Too many boolean options, maybe convert them to more descriptive
105 # Note: ask_key conflicts with batch mode
108 raise errors.ProgrammerError("SSH call requested conflicting options")
110 options.append("-oBatchMode=yes")
112 if strict_host_check:
113 options.append("-oStrictHostKeyChecking=yes")
115 options.append("-oStrictHostKeyChecking=no")
119 "-oStrictHostKeyChecking=ask",
124 def BuildCmd(self, hostname, user, command, batch=True, ask_key=False,
125 tty=False, use_cluster_key=True, strict_host_check=True):
126 """Build an ssh command to execute a command on a remote node.
128 @param hostname: the target host, string
129 @param user: user to auth as
130 @param command: the command
131 @param batch: if true, ssh will run in batch mode with no prompting
132 @param ask_key: if true, ssh will run with
133 StrictHostKeyChecking=ask, so that we can connect to an
134 unknown host (not valid in batch mode)
135 @param use_cluster_key: whether to expect and use the
136 cluster-global SSH key
137 @param strict_host_check: whether to check the host's SSH key at all
139 @return: the ssh call to run 'command' on the remote host.
142 argv = [constants.SSH, "-q"]
143 argv.extend(self._BuildSshOptions(batch, ask_key, use_cluster_key,
147 argv.extend(["%s@%s" % (user, hostname), command])
150 def Run(self, *args, **kwargs):
151 """Runs a command on a remote node.
153 This method has the same return value as `utils.RunCmd()`, which it
156 Args: see SshRunner.BuildCmd.
158 @rtype: L{utils.RunResult}
159 @return: the result as from L{utils.RunCmd()}
162 return utils.RunCmd(self.BuildCmd(*args, **kwargs))
164 def CopyFileToNode(self, node, filename):
165 """Copy a file to another node with scp.
167 @param node: node in the cluster
168 @param filename: absolute pathname of a local file
171 @return: the success of the operation
174 if not os.path.isabs(filename):
175 logging.error("File %s must be an absolute path", filename)
178 if not os.path.isfile(filename):
179 logging.error("File %s does not exist", filename)
182 command = [constants.SCP, "-q", "-p"]
183 command.extend(self._BuildSshOptions(True, False, True, True))
184 command.append(filename)
185 command.append("%s:%s" % (node, filename))
187 result = utils.RunCmd(command)
190 logging.error("Copy to node %s failed (%s) error %s,"
192 node, result.fail_reason, result.output, result.cmd)
194 return not result.failed
196 def VerifyNodeHostname(self, node):
197 """Verify hostname consistency via SSH.
199 This functions connects via ssh to a node and compares the hostname
200 reported by the node to the name with have (the one that we
203 This is used to detect problems in ssh known_hosts files
204 (conflicting known hosts) and incosistencies between dns/hosts
205 entries and local machine names
207 @param node: nodename of a host to check; can be short or
208 full qualified hostname
210 @return: (success, detail), where:
211 - success: True/False
212 - detail: string with details
215 retval = self.Run(node, 'root', 'hostname')
219 output = retval.output
221 msg += ": %s" % output
223 msg += ": %s (no output)" % retval.fail_reason
224 logging.error("Command %s failed: %s" % (retval.cmd, msg))
227 remotehostname = retval.stdout.strip()
229 if not remotehostname or remotehostname != node:
230 return False, "hostname mismatch, got %s" % remotehostname
232 return True, "host matches"
235 def WriteKnownHostsFile(cfg, file_name):
236 """Writes the cluster-wide equally known_hosts file.
239 utils.WriteFile(file_name, mode=0600,
240 data="%s ssh-rsa %s\n" % (cfg.GetClusterName(),