SSH Service Accounts

On RedHat version 5 and above there is an ssh-copy-id utility that may be used; however, for lower revisions you will need to copy the following script to /usr/bin/ssh-copy-id and make it executable before following the remainder of the steps.

#!/bin/sh
# Shell script to install your identity.pub on a remote machine
# Takes the remote machine name as an argument.
# Obviously, the remote machine must accept password authentication,
# or one of the other keys in your ssh-agent, for this to work.

ID_FILE="${HOME}/.ssh/identity.pub"

if [ "-i" = "$1" ]; then
  shift
  # check if we have 2 parameters left, if so the first is the new ID file
  if [ -n "$2" ]; then
    if expr "$1" : ".*.pub" ; then
      ID_FILE="$1"
    else
      ID_FILE="$1.pub"
    fi
    shift         # and this should leave $1 as the target name
  fi
 else
  if [ x$SSH_AUTH_SOCK != x ] ; then
    GET_ID="$GET_ID ssh-add -L"
  fi
fi
 
if [ -z "`eval $GET_ID`" ] && [ -r "${ID_FILE}" ] ; then
   GET_ID="cat ${ID_FILE}"
fi

if [ -z "`eval $GET_ID`" ]; then
  echo "$0: ERROR: No identities found" >&2
  exit 1
fi

if [ "$#" -lt 1 ] || [ "$1" = "-h" ] || [ "$1" = "--help" ]; then
  echo "Usage: $0 [-i [identity_file]] [user@]machine" >&2
  exit 1
fi

{ eval "$GET_ID" ; } | ssh $1 "umask 077; test -d .ssh || mkdir .ssh ; cat >> .ssh/authorized_keys" || exit 1

cat <<EOF
Now try logging into the machine, with "ssh '$1'", and check in:

  .ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

EOF

Logon as or create the service account on all machines required:

useradd -u 199 -s /bin/false serviceacct

echo password1 | passwd --stdin servicacct

Create your DSA key pair:

ssh-keygen -t dsa

Don't enter a password, just hit Enter key three times in quick succession.

Copy your new public ID to all the servers:

logon or su to the service account and run...

ssh-copy-id -i ~/.ssh/id_dsa.pub remoteservername

For bi-directional connectivity repeat the procedure on the remote server pointing back to the original.