ssh script returns 255 error

Question

In my code I have the following to run a remote script   ssh root host domain com  sh  home user backup mysql sh    For some reason it keeps 255 ing on me  Any ideas   I can SSH into the box just fine  passless keys setup    REMOTE SCRIPT   MUSER  root   MPASS  123123  MHOST  127 0 0 1  VERBOSE 0      Set bins path     GZIP  bin gzip MYSQL  usr bin mysql MYSQLDUMP  usr bin mysqldump RM  bin rm MKDIR  bin mkdir MYSQLADMIN  usr bin mysqladmin GREP  bin grep      Setup dump directory     BAKRSNROOT   snapshots tmp                                            ----  No Editing below  ------                                              Default time format     TIME FORMAT   H  M  S P       Make a backup     backup mysql rsnapshot            local DBS     MYSQL -u  MUSER -h  MHOST -p MPASS -Bse  show databases            local db                 -d  BAKRSNROOT    amp  amp    MKDIR  -p  BAKRSNROOT           RM  -f  BAKRSNROOT    gt  dev null 2 gt  amp 1            VERBOSE -eq 1    amp  amp  echo      Dumping MySQL Database                 VERBOSE -eq 1    amp  amp  echo -n  Database gt            for db in  DBS         do                 local tTime   date     TIME FORMAT                    local FILE    BAKRSNROOT    db    tTime  gz                     VERBOSE -eq 1    amp  amp  echo -n   db                      MYSQLDUMP  --single-transaction -u   MUSER  -h   MHOST  -p  MPASS   db     GZIP  -9  gt   FILE         done                    VERBOSE -eq 1    amp  amp  echo                       VERBOSE -eq 1    amp  amp  echo      Backup done   files wrote to  BAKRSNROOT              Die on demand with message     die            echo              exit 999        Make sure bins exists   else die verify bins                -x  GZIP    amp  amp  die  File  GZIP does not exists  Make sure correct path is set in  0               -x  MYSQL    amp  amp  die  File  MYSQL does not exists  Make sure correct path is set in  0               -x  MYSQLDUMP    amp  amp  die  File  MYSQLDUMP does not exists  Make sure correct path is set in  0               -x  RM    amp  amp  die  File  RM does not exists  Make sure correct path is set in  0               -x  MKDIR    amp  amp  die  File  MKDIR does not exists  Make sure correct path is set in  0               -x  MYSQLADMIN    amp  amp  die  File  MYSQLADMIN does not exists  Make sure correct path is set in  0               -x  GREP    amp  amp  die  File  GREP does not exists  Make sure correct path is set in  0          Make sure we can connect to server     else die verify mysql connection             MYSQLADMIN  -u  MUSER -h  MHOST -p MPASS ping    GREP  alive  gt  dev null              -eq 0      die  Error  Cannot connect to MySQL Server  Make sure username and password are set correctly in  0         main      verify bins verify mysql connection backup mysql rsnapshot

User · Answer

I was stumped by this  Once I got passed the 255 problem    I ended up with a mysterious error code 1   This is the foo to get that resolved    pssh -x  -tt  -h HOSTFILELIST -P  sudo yum -y install glibc    -P means write the output out as you go and is optional  But the -x  -tt  trick is what forces a psuedo tty to be allocated   You can get a clue what the error code 1 means this if you try   ssh AHOST  sudo yum -y install glibc    You may see    slc bastion-ci     ssh MYHOST  sudo yum -y install glibc  sudo  sorry  you must have a tty to run sudo  slc bastion-ci     echo    1   Notice the return code for this is 1  which is what pssh is reporting to you   I found this -x -tt trick here   Also note that turning on verbose mode  pssh --verbose  for these cases does nothing to help you

User · Answer

It can very much be an ssh-agent issue   Check whether there is an ssh-agent PID currently running with eval    ssh-agent -s    Check whether your identity is added with ssh-add -l and if not  add it with ssh-add  lt pathToYourRSAKey gt     Then try again your ssh command  or any other command that spawns ssh daemons  like autossh for example  that returned 255

User · Answer

If there s a problem with authentication or connection  such as not being able to read a password from the terminal  ssh will exit with 255 without being able to run your actual script  Verify to make sure you can run  true  instead  to see if the ssh connection is established successfully

User · Answer

This error will also occur when using pdsh to hosts which are not contained in your  known hosts  file   I was able to correct this by SSH ing into each host manually and accepting the question  Do you want to add this to known hosts

User · Answer

SSH Very critical issue on Production  SSH-debug1  Exit status 255  I was working with Live Server and lots stuff stuck  I try many things to fix but exact issue of 255 don t figure out   Even I had resolved issue 100      Replace my sshd config file from similar other my debian server      root snippetbucket com    cp sshd config sshd config snippetbucket com bkp   keep my backup file      root snippetbucket com    echo      sshd config      root snippetbucket com    nano sshd config    replaced all content with other    exact same server      root snippetbucket com    sudo service ssh restart    normally restart server   That s 100  resolve my issue immediate       SnippetBucket-Tip  Always take backup of ssh related files  which help on quick restoration    Note  After apply given changes you need to exit rescue mode and reboot your vps   dedicated server normally  than your ssh connection works   During rescue mode ssh don t allow user to login as normally  only rescue ssh related login and password works

User · Answer

This is usually happens when the remote is down unavailable  or the remote machine doesn t have ssh installed  or a firewall doesn t allow a connection to be established to the remote host   ssh returns 255 when an error occurred or 255 is returned by the remote script    EXIT STATUS       ssh exits with the exit status of the remote command or      with 255 if an error occurred    Usually you would an error message something similar to   ssh  connect to host host domain com port 22  No route to host   Or  ssh  connect to host HOSTNAME port 22  Connection refused   Check-list    What happens if you run the ssh command directly from the command line   Are you able to ping that machine  Does the remote has ssh installed  If installed  then is the ssh service running

User · Answer

As  wes-floyd and  zpon wrote  add these parameters to SSH to bypass  Are you sure you want to continue connecting  yes no     -o UserKnownHostsFile  dev null -o StrictHostKeyChecking no

User · Answer

If above didn t help  check if locale is valid on client and server  https   www linuxbabe com linux-server fix-ssh-locale-environment-variable-error How do not pass locale through ssh

[linux] ssh script returns 255 error

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