ganeti.ssh

80 """Wrapper for SSH commands. 81 82 """

83 - def __init__(self, cluster_name, ipv6=False):

84 """Initializes this class. 85 86 @type cluster_name: str 87 @param cluster_name: name of the cluster 88 @type ipv6: bool 89 @param ipv6: If true, force ssh to use IPv6 addresses only 90 91 """ 92 self.cluster_name = cluster_name 93 self.ipv6 = ipv6

94

95 - def _BuildSshOptions(self, batch, ask_key, use_cluster_key, 96 strict_host_check, private_key=None, quiet=True):

97 """Builds a list with needed SSH options. 98 99 @param batch: same as ssh's batch option 100 @param ask_key: allows ssh to ask for key confirmation; this 101 parameter conflicts with the batch one 102 @param use_cluster_key: if True, use the cluster name as the 103 HostKeyAlias name 104 @param strict_host_check: this makes the host key checking strict 105 @param private_key: use this private key instead of the default 106 @param quiet: whether to enable -q to ssh 107 108 @rtype: list 109 @return: the list of options ready to use in L{utils.process.RunCmd} 110 111 """ 112 options = [ 113 "-oEscapeChar=none", 114 "-oHashKnownHosts=no", 115 "-oGlobalKnownHostsFile=%s" % constants.SSH_KNOWN_HOSTS_FILE, 116 "-oUserKnownHostsFile=/dev/null", 117 "-oCheckHostIp=no", 118 ] 119 120 if use_cluster_key: 121 options.append("-oHostKeyAlias=%s" % self.cluster_name) 122 123 if quiet: 124 options.append("-q") 125 126 if private_key: 127 options.append("-i%s" % private_key) 128 129 # TODO: Too many boolean options, maybe convert them to more descriptive 130 # constants. 131 132 # Note: ask_key conflicts with batch mode 133 if batch: 134 if ask_key: 135 raise errors.ProgrammerError("SSH call requested conflicting options") 136 137 options.append("-oBatchMode=yes") 138 139 if strict_host_check: 140 options.append("-oStrictHostKeyChecking=yes") 141 else: 142 options.append("-oStrictHostKeyChecking=no") 143 144 else: 145 # non-batch mode 146 147 if ask_key: 148 options.append("-oStrictHostKeyChecking=ask") 149 elif strict_host_check: 150 options.append("-oStrictHostKeyChecking=yes") 151 else: 152 options.append("-oStrictHostKeyChecking=no") 153 154 if self.ipv6: 155 options.append("-6") 156 157 return options

158

159 - def BuildCmd(self, hostname, user, command, batch=True, ask_key=False, 160 tty=False, use_cluster_key=True, strict_host_check=True, 161 private_key=None, quiet=True):

162 """Build an ssh command to execute a command on a remote node. 163 164 @param hostname: the target host, string 165 @param user: user to auth as 166 @param command: the command 167 @param batch: if true, ssh will run in batch mode with no prompting 168 @param ask_key: if true, ssh will run with 169 StrictHostKeyChecking=ask, so that we can connect to an 170 unknown host (not valid in batch mode) 171 @param use_cluster_key: whether to expect and use the 172 cluster-global SSH key 173 @param strict_host_check: whether to check the host's SSH key at all 174 @param private_key: use this private key instead of the default 175 @param quiet: whether to enable -q to ssh 176 177 @return: the ssh call to run 'command' on the remote host. 178 179 """ 180 argv = [constants.SSH] 181 argv.extend(self._BuildSshOptions(batch, ask_key, use_cluster_key, 182 strict_host_check, private_key, 183 quiet=quiet)) 184 if tty: 185 argv.extend(["-t", "-t"]) 186 argv.extend(["%s@%s" % (user, hostname), command]) 187 return argv

188

189 - def Run(self, *args, **kwargs):

190 """Runs a command on a remote node. 191 192 This method has the same return value as `utils.RunCmd()`, which it 193 uses to launch ssh. 194 195 Args: see SshRunner.BuildCmd. 196 197 @rtype: L{utils.process.RunResult} 198 @return: the result as from L{utils.process.RunCmd()} 199 200 """ 201 return utils.RunCmd(self.BuildCmd(*args, **kwargs))

202

203 - def CopyFileToNode(self, node, filename):

204 """Copy a file to another node with scp. 205 206 @param node: node in the cluster 207 @param filename: absolute pathname of a local file 208 209 @rtype: boolean 210 @return: the success of the operation 211 212 """ 213 if not os.path.isabs(filename): 214 logging.error("File %s must be an absolute path", filename) 215 return False 216 217 if not os.path.isfile(filename): 218 logging.error("File %s does not exist", filename) 219 return False 220 221 command = [constants.SCP, "-p"] 222 command.extend(self._BuildSshOptions(True, False, True, True)) 223 command.append(filename) 224 if netutils.IP6Address.IsValid(node): 225 node = netutils.FormatAddress((node, None)) 226 227 command.append("%s:%s" % (node, filename)) 228 229 result = utils.RunCmd(command) 230 231 if result.failed: 232 logging.error("Copy to node %s failed (%s) error %s," 233 " command was %s", 234 node, result.fail_reason, result.output, result.cmd) 235 236 return not result.failed

237

238 - def VerifyNodeHostname(self, node):

239 """Verify hostname consistency via SSH. 240 241 This functions connects via ssh to a node and compares the hostname 242 reported by the node to the name with have (the one that we 243 connected to). 244 245 This is used to detect problems in ssh known_hosts files 246 (conflicting known hosts) and inconsistencies between dns/hosts 247 entries and local machine names 248 249 @param node: nodename of a host to check; can be short or 250 full qualified hostname 251 252 @return: (success, detail), where: 253 - success: True/False 254 - detail: string with details 255 256 """ 257 retval = self.Run(node, "root", "hostname --fqdn", quiet=False) 258 259 if retval.failed: 260 msg = "ssh problem" 261 output = retval.output 262 if output: 263 msg += ": %s" % output 264 else: 265 msg += ": %s (no output)" % retval.fail_reason 266 logging.error("Command %s failed: %s", retval.cmd, msg) 267 return False, msg 268 269 remotehostname = retval.stdout.strip() 270 271 if not remotehostname or remotehostname != node: 272 if node.startswith(remotehostname + "."): 273 msg = "hostname not FQDN" 274 else: 275 msg = "hostname mismatch" 276 return False, ("%s: expected %s but got %s" % 277 (msg, node, remotehostname)) 278 279 return True, "host matches"

Source Code for Module ganeti.ssh