Using the screen command#

The screen command is available to execute long-running commands (for example, when upgrading) in the background.

The following commands require the running of screen:

  • cluster provision

  • cluster upgrade

  • app template

  • voss export type <args>

  • voss export group <args>

  • voss subscriber_data_export

A message is displayed to indicate that screen should be run first:

This is a potentially long-running command and should be executed in a screen session
Run `screen` and then execute the command again

The use of screen is not affected by the use of the --force parameter with any of these commands.

The commands then run in a screen session that can be reconnected. The standard screen command parameters are available, in particular:

  • screen - start a new session

  • screen -ls - show sessions already available

  • screen -r [screen PID] - reconnect to a disconnected session

The version of screen used in VOSS Automate also supports the creation of a log file. If long-running commands will be run, the log file captures screen console output up to the session timeout. A message shows:

timed out waiting for input: auto-logout

To create a screen log file:

  1. Run screen and wait for screen to open.

  2. Press <Ctrl>-a then : (colon). This will enter screen command mode at the bottom of the console.

  3. Create your screen logfile in the media/ directory:

    1. In screen command mode, type logfile media/<screen-logfilename>.log

    2. Press <Enter>

    3. Press <Ctrl>-a and then H to start writing to the log file

    4. Run your commands.

If the screen session times out, you can obtain console output from the log file, for example:

$ sftp platform@<host>:media/<screen-logfilename>.log