Précisons la clé

softwares/secure_tunnel.sls

@@ -21,6 +21,7 @@
     - template: jinja
     - defaults:
       ANS_ADDR_TARGET: {{ANS_ADDR_TARGET}}
+      KEY_NAME: {{KEY_NAME}}
 
 'secure_tunnel_default_file':
   file.managed:

templates/secure-tunnel.service

@@ -6,7 +6,7 @@ After=network.target
 [Service]
 User=${ANS_REMOTE_USER}
 EnvironmentFile=/etc/default/secure-tunnel
-ExecStart=/usr/bin/ssh -p ${REMOTE_PORT} -NT -o StrictHostKeyChecking=no -o ServerAliveInterval=60 -o ExitOnForwardFailure=yes -R ${RTARGET_PORT}:localhost:22 ${ANS_TARGET_USER}@${TARGET}
+ExecStart=/usr/bin/ssh -p ${REMOTE_PORT} -NT -i $HOME/.ssh/{{KEY_NAME}} -o StrictHostKeyChecking=no -o ServerAliveInterval=60 -o ExitOnForwardFailure=yes -R ${RTARGET_PORT}:localhost:22 ${ANS_TARGET_USER}@${TARGET}
 
 # Restart every >2 seconds to avoid StartLimitInterval failure
 RestartSec=5