Updated July 27, 2016
After you attempt to push an upgrade to a Linux Agent from the LEM console, the Update Status field shows a red exclamation mark icon and displays "Error" in the tooltip.
The manager.log file in the CMC shell displays the following error during the agent upgrade attempt. (To view the log file, go to Manager > Showlog.)
Execute failed: java.io.IOException: Cannot run program "at": error=2, No such file or directory
The Linux at command is not installed or was not included with your Linux distribution.
The agent upgrade process requires the at command to be installed.
The solution to this issue is to either install the package for that command (that process may vary depending on your Linux distribution) or simply run the updated version of the Linux agent local installer found on the Customer Portal. For details on that process, see SolarWinds LEM Agent Installer for Linux.