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.
29 from ganeti import logger
30 from ganeti import utils
31 from ganeti import errors
32 from ganeti import constants
33 from ganeti import ssconf
37 "-oGlobalKnownHostsFile=%s" % constants.SSH_KNOWN_HOSTS_FILE,
38 "-oUserKnownHostsFile=/dev/null",
41 # Note: BATCH_MODE conflicts with ASK_KEY
45 "-oStrictHostKeyChecking=yes",
50 "-oHashKnownHosts=no",
51 "-oStrictHostKeyChecking=ask",
55 def GetUserFiles(user, mkdir=False):
56 """Return the paths of a user's ssh files.
58 The function will return a triplet (priv_key_path, pub_key_path,
59 auth_key_path) that are used for ssh authentication. Currently, the
60 keys used are DSA keys, so this function will return:
61 (~user/.ssh/id_dsa, ~user/.ssh/id_dsa.pub,
62 ~user/.ssh/authorized_keys).
64 If the optional parameter mkdir is True, the ssh directory will be
65 created if it doesn't exist.
67 Regardless of the mkdir parameters, the script will raise an error
68 if ~user/.ssh is not a directory.
71 user_dir = utils.GetHomeDir(user)
73 raise errors.OpExecError("Cannot resolve home of user %s" % user)
75 ssh_dir = os.path.join(user_dir, ".ssh")
76 if not os.path.lexists(ssh_dir):
79 os.mkdir(ssh_dir, 0700)
80 except EnvironmentError, err:
81 raise errors.OpExecError("Can't create .ssh dir for user %s: %s" %
83 elif not os.path.isdir(ssh_dir):
84 raise errors.OpExecError("path ~%s/.ssh is not a directory" % user)
86 return [os.path.join(ssh_dir, base)
87 for base in ["id_dsa", "id_dsa.pub", "authorized_keys"]]
91 """Wrapper for SSH commands.
94 def __init__(self, sstore=None):
96 self.sstore = ssconf.SimpleStore()
100 def _GetHostKeyAliasOption(self):
101 return "-oHostKeyAlias=%s" % self.sstore.GetClusterName()
103 def BuildCmd(self, hostname, user, command, batch=True, ask_key=False,
104 tty=False, use_cluster_key=True):
105 """Build an ssh command to execute a command on a remote node.
108 hostname: the target host, string
109 user: user to auth as
111 batch: if true, ssh will run in batch mode with no prompting
112 ask_key: if true, ssh will run with StrictHostKeyChecking=ask, so that
113 we can connect to an unknown host (not valid in batch mode)
114 use_cluster_key: Whether to expect and use the cluster-global SSH key
117 The ssh call to run 'command' on the remote host.
120 argv = [constants.SSH, "-q"]
121 argv.extend(KNOWN_HOSTS_OPTS)
123 argv.append(self._GetHostKeyAliasOption())
125 # if we are in batch mode, we can't ask the key
127 raise errors.ProgrammerError("SSH call requested conflicting options")
128 argv.extend(BATCH_MODE_OPTS)
130 argv.extend(ASK_KEY_OPTS)
133 argv.extend(["%s@%s" % (user, hostname), command])
136 def Run(self, hostname, user, command, batch=True, ask_key=False,
137 use_cluster_key=True):
138 """Runs a command on a remote node.
140 This method has the same return value as `utils.RunCmd()`, which it
144 hostname: the target host, string
145 user: user to auth as
147 batch: if true, ssh will run in batch mode with no prompting
148 ask_key: if true, ssh will run with StrictHostKeyChecking=ask, so that
149 we can connect to an unknown host (not valid in batch mode)
152 `utils.RunResult` like `utils.RunCmd()`
155 return utils.RunCmd(self.BuildCmd(hostname, user, command, batch=batch,
157 use_cluster_key=use_cluster_key))
159 def CopyFileToNode(self, node, filename):
160 """Copy a file to another node with scp.
163 node: node in the cluster
164 filename: absolute pathname of a local file
170 if not os.path.isabs(filename):
171 logger.Error("file %s must be an absolute path" % (filename))
174 if not os.path.isfile(filename):
175 logger.Error("file %s does not exist" % (filename))
178 command = [constants.SCP, "-q", "-p"]
179 command.extend(KNOWN_HOSTS_OPTS)
180 command.extend(BATCH_MODE_OPTS)
181 command.append(self._GetHostKeyAliasOption())
182 command.append(filename)
183 command.append("%s:%s" % (node, filename))
185 result = utils.RunCmd(command)
188 logger.Error("copy to node %s failed (%s) error %s,"
190 (node, result.fail_reason, result.output, result.cmd))
192 return not result.failed
194 def VerifyNodeHostname(self, node):
195 """Verify hostname consistency via SSH.
197 This functions connects via ssh to a node and compares the hostname
198 reported by the node to the name with have (the one that we
201 This is used to detect problems in ssh known_hosts files
202 (conflicting known hosts) and incosistencies between dns/hosts
203 entries and local machine names
206 node: nodename of a host to check. can be short or full qualified hostname
212 detail: String with details
215 retval = self.Run(node, 'root', 'hostname')
219 output = retval.output
221 msg += ": %s" % output
224 remotehostname = retval.stdout.strip()
226 if not remotehostname or remotehostname != node:
227 return False, "hostname mismatch, got %s" % remotehostname
229 return True, "host matches"
232 def WriteKnownHostsFile(cfg, sstore, file_name):
233 """Writes the cluster-wide equally known_hosts file.
236 utils.WriteFile(file_name, mode=0700,
237 data="%s ssh-rsa %s\n" % (sstore.GetClusterName(),