When installation of NoMachine fails with error:

NX> 701 ERROR: Cannot change context for: /etc/NX/nxnode to: shell_exec_t.

it's likely that the /etc/NX/nxnode script is missing. A similar error can be issued also when the /etc/NX/nxserver script is missing. One of the reason why such scripts are not put in place during the installation is that the /tmp directory on the system is used as separate partition and it is mounted with the 'noexec' option. In this case installation cannot be completed succesfully because file permissions are changed while unpacking to /tmp directory.

Workaround is: 

1. Remount the /tmp partition with the 'exec' option:

# mount -o remount,exec /tmp

2. Then, install the NoMachine package.

3. Finally remount the /tmp directory with the original 'noexec' option:

# mount -o remount,noexec /tmp