1CONDOR_SSH_TO_JOB(1)            HTCondor Manual           CONDOR_SSH_TO_JOB(1)
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NAME

6       condor_ssh_to_job - HTCondor Manual
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8       create an ssh session to a running job
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10

SYNOPSIS

12       condor_ssh_to_job [-help ]
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14       condor_ssh_to_job [-debug ] [-name schedd-name] [-pool pool-name] [-ssh
15       ssh-command]     [-keygen-options     ssh-keygen-options]      [-shells
16       shell1,shell2,...]  [-auto-retry  ]  [-remove-on-interrupt  ] cluster |
17       cluster.process | cluster.process.node [remote-command ]
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DESCRIPTION

20       condor_ssh_to_job creates an ssh session to a running job. The  job  is
21       specified  with the argument. If only the job cluster id is given, then
22       the job process id defaults to the value 0.
23
24       condor_ssh_to_job is available  in  Unix  HTCondor  distributions,  and
25       works with two kinds of jobs: those in the vanilla, vm, java, local, or
26       parallel universes, and those jobs in the grid universe which  use  EC2
27       resources. It will not work with other grid universe jobs.
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29       For  jobs  in  the vanilla, vm, java, local, or parallel universes, the
30       user must be the owner of the job or must be a queue  super  user,  and
31       both  the  condor_schedd  and  condor_starter  daemons  must allow con‐
32       dor_ssh_to_job access. If no remote-command is specified,  an  interac‐
33       tive  shell  is  created.  An alternate ssh program such as sftp may be
34       specified, using the -ssh option, for uploading and downloading files.
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36       The remote command or shell runs with the same user id as  the  running
37       job,  and  it is initialized with the same working directory. The envi‐
38       ronment is initialized to be the same as that  of  the  job,  plus  any
39       changes  made  by the shell setup scripts and any environment variables
40       passed by the ssh client. In addition, the environment  variable  _CON‐
41       DOR_JOB_PIDS  is  defined. It is a space-separated list of PIDs associ‐
42       ated with the job. At a minimum, the list will contain the PID  of  the
43       process  started  when  the  job was launched, and it will be the first
44       item in the list. It may contain additional  PIDs  of  other  processes
45       that the job has created.
46
47       The ssh session and all processes it creates are treated by HTCondor as
48       though they are processes belonging to the job. If  the  slot  is  pre‐
49       empted  or suspended, the ssh session is killed or suspended along with
50       the job. If the job exits before the ssh session finishes, the slot re‐
51       mains  in  the  Claimed Busy state and is treated as though not all job
52       processes have exited until all ssh sessions are closed.  Multiple  ssh
53       sessions may be created to the same job at the same time. Resource con‐
54       sumption of the sshd process and all processes spawned by it are  moni‐
55       tored  by  the  condor_starter  as though these processes belong to the
56       job, so any policies such as PREEMPT that enforce a limit  on  resource
57       consumption  also  take into account resources consumed by the ssh ses‐
58       sion.
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60       condor_ssh_to_job stores ssh keys in temporary  files  within  a  newly
61       created  and uniquely named directory. The newly created directory will
62       be within the directory defined by  the  environment  variable  TMPDIR.
63       When  the ssh session is finished, this directory and the ssh keys con‐
64       tained within it are removed.
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66       See the HTCondor administrator's manual section  on  configuration  for
67       details of the configuration variables related to condor_ssh_to_job.
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69       An  ssh  session works by first authenticating and authorizing a secure
70       connection between condor_ssh_to_job and the condor_starter daemon, us‐
71       ing  HTCondor  protocols.  The condor_starter generates an ssh key pair
72       and sends it securely to  condor_ssh_to_job.  Then  the  condor_starter
73       spawns sshd in inetd mode with its stdin and stdout attached to the TCP
74       connection from condor_ssh_to_job.  condor_ssh_to_job acts as  a  proxy
75       for the ssh client to communicate with sshd, using the existing connec‐
76       tion authorized by HTCondor. At no point is sshd listening on the  net‐
77       work  for connections or running with any privileges other than that of
78       the user identity running the job. If CCB is being used to enable  con‐
79       nectivity  to  the  execute  node from outside of a firewall or private
80       network, condor_ssh_to_job is able to make use of CCB in order to  form
81       the ssh connection.
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83       The  login  shell of the user id running the job is used to run the re‐
84       quested  command,  sshd  subsystem,  or  interactive  shell.  This   is
85       hard-coded  behavior  in OpenSSH and cannot be overridden by configura‐
86       tion. This means that condor_ssh_to_job access is effectively  disabled
87       if  the  login  shell  disables  access,  as  in  the  example programs
88       /bin/true and /sbin/nologin.
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90       condor_ssh_to_job is intended to work with OpenSSH as installed in typ‐
91       ical  environments.  It  does not work on Windows platforms. If the ssh
92       programs are installed in non-standard locations,  then  the  paths  to
93       these  programs will need to be customized within the HTCondor configu‐
94       ration. Versions of ssh other than OpenSSH  may  work,  but  they  will
95       likely  require  additional  configuration  of  command-line arguments,
96       changes to the sshd configuration template file, and possibly modifica‐
97       tion  of the $(LIBEXEC)/condor_ssh_to_job_sshd_setup script used by the
98       condor_starter to set up sshd.
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100       For jobs in the grid universe which use EC2 resources, a  request  that
101       HTCondor  have  the  EC2  service  create a new key pair for the job by
102       specifying ec2_keypair_file causes condor_ssh_to_job to attempt to con‐
103       nect  to  the corresponding instance via ssh. This attempts invokes ssh
104       directly, bypassing the HTCondor networking layer. It supplies ssh with
105       the  public  DNS name of the instance and the name of the file with the
106       new key pair's private key. For the connection to succeed, the instance
107       must  have  started an ssh server, and its security group(s) must allow
108       connections on port 22. Conventionally, images will allow logins  using
109       the key pair on a single specific account. Because ssh defaults to log‐
110       ging in as the current user, the -l <username> option or its equivalent
111       for  other versions of ssh will be needed as part of the remote-command
112       argument. Although the -X option does not apply to EC2 jobs, adding  -X
113       or -Y to the remote-command argument can duplicate the effect.
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OPTIONS

116          -help  Display brief usage information and exit.
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118          -debug Causes  debugging  information to be sent to stderr, based on
119                 the value of the configuration variable TOOL_DEBUG.
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121          -name schedd-name
122                 Specify an alternate condor_schedd, if  the  default  (local)
123                 one is not desired.
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125          -pool pool-name
126                 Specify an alternate HTCondor pool, if the default one is not
127                 desired. Does not apply to EC2 jobs.
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129          -ssh ssh-command
130                 Specify an alternate ssh program to run in place of ssh,  for
131                 example  sftp  or  scp. Additional arguments are specified as
132                 ssh-command. Since the arguments  are  delimited  by  spaces,
133                 place double quote marks around the whole command, to prevent
134                 the shell from splitting it into multiple arguments  to  con‐
135                 dor_ssh_to_job.   If  any  arguments must contain spaces, en‐
136                 close them within single quotes. Does not apply to EC2 jobs.
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138          -keygen-options ssh-keygen-options
139                 Specify additional arguments to the ssh_keygen  program,  for
140                 creating  the  ssh  key  that is used for the duration of the
141                 session.  For example, a different number of  bits  could  be
142                 used,  or a different key type than the default. Does not ap‐
143                 ply to EC2 jobs.
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145          -shells shell1,shell2,...
146                 Specify a  comma-separated  list  of  shells  to  attempt  to
147                 launch.  If  the first shell does not exist on the remote ma‐
148                 chine, then the following ones in the list will be tried.  If
149                 none of the specified shells can be found, /bin/sh is used by
150                 default. If this option is not specified, it defaults to  the
151                 environment  variable SHELL from within the condor_ssh_to_job
152                 environment. Does not apply to EC2 jobs.
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154          -auto-retry
155                 Specifies  that  if  the  job  is  not  yet   running,   con‐
156                 dor_ssh_to_job  should keep trying periodically until it suc‐
157                 ceeds or encounters some other error.
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159          -remove-on-interrupt
160                 If specified, attempt to remove the job  from  the  queue  if
161                 condor_ssh_to_job  is  interrupted  via a CTRL-c or otherwise
162                 terminated abnormally.
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164          -X     Enable X11 forwarding. Does not apply to EC2 jobs.
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166          -x     Disable X11 forwarding.
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EXAMPLES

169          % condor_ssh_to_job 32.0
170          Welcome to slot2@tonic.cs.wisc.edu!
171          Your condor job is running with pid(s) 65881.
172          % gdb -p 65881
173          (gdb) where
174          ...
175          % logout
176          Connection to condor-job.tonic.cs.wisc.edu closed.
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178       To upload or download files interactively with sftp:
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180          % condor_ssh_to_job -ssh sftp 32.0
181          Connecting to condor-job.tonic.cs.wisc.edu...
182          sftp> ls
183          ...
184          sftp> get outputfile.dat
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186       This example shows downloading a file from the job with scp. The string
187       "remote"  is  used  in  place of a host name in this example. It is not
188       necessary to insert the correct remote host name, or even a valid  one,
189       because the connection to the job is created automatically.  Therefore,
190       the placeholder string "remote" is perfectly fine.
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192          % condor_ssh_to_job -ssh scp 32 remote:outputfile.dat .
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194       This example uses condor_ssh_to_job to accomplish the task  of  running
195       rsync to synchronize a local file with a remote file in the job's work‐
196       ing directory. Job id 32.0 is used in place of a host name in this  ex‐
197       ample. This causes rsync to insert the expected job id in the arguments
198       to condor_ssh_to_job.
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200          % rsync -v -e "condor_ssh_to_job" 32.0:outputfile.dat .
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202       Note that condor_ssh_to_job was added to HTCondor in version  7.3.   If
203       one  uses  condor_ssh_to_job  to connect to a job on an execute machine
204       running a version of HTCondor older than the 7.3  series,  the  command
205       will fail with the error message
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207          Failed to send CREATE_JOB_OWNER_SEC_SESSION to starter
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EXIT STATUS

210       condor_ssh_to_job will exit with a non-zero status value if it fails to
211       set up an ssh session. If it succeeds, it will  exit  with  the  status
212       value of the remote command or shell.
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AUTHOR

215       HTCondor Team
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218       1990-2021,  Center for High Throughput Computing, Computer Sciences De‐
219       partment, University of Wisconsin-Madison, Madison,  WI,  US.  Licensed
220       under the Apache License, Version 2.0.
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2258.8                              Aug 23, 2021             CONDOR_SSH_TO_JOB(1)
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