## Process Isolation Overview

In older versions of Ansible Tower, we used a system called `proot` to isolate Tower job processes from the rest of the system.

Tower version 3.1 and later switched to using `bubblewrap`, which is a much lighter-weight and maintained process isolation system.

Tower 3.5 and later uses the process isolation feature in Ansible runner to achieve process isolation.


### Activating Process Isolation

`bubblewrap` is enabled by default; it can be turned off via Tower Config or from a Tower settings file:

    AWX_PROOT_ENABLED = False

Process isolation, when enabled, will be used for the following Job Types:

* Job Templates - Launching jobs from regular job templates
* Ad-hoc Commands - Launching ad-hoc commands against one or more hosts in inventory


### Tunables

Process Isolation will, by default, hide the following directories from the tasks mentioned above:

* `/etc/tower` - To prevent exposing Tower configuration
* `/var/lib/awx` - With the exception of the current project being used (for regular job templates)
* `/var/log`
* `/tmp` (or whatever the system `temp dir` is) - With the exception of the processes's own temp files

If there is other information on the system that is sensitive and should be hidden, it can be added via the Tower Configuration Screen
or by updating the following entry in a tower settings file:

    AWX_PROOT_HIDE_PATHS = ['/list/of/', '/paths']

If there are any directories that should specifically be exposed that can be set in a similar way:

    AWX_PROOT_SHOW_PATHS = ['/list/of/', '/paths']

By default, the system will use the system's `tmp dir` (`/tmp` by default) as its staging area. This can be changed via the following setting:

    AWX_PROOT_BASE_PATH = "/opt/tmp"


### Project Folder Isolation

Starting in AWX versions above 6.0.0, the project folder will be copied for each job run.
This allows playbooks to make local changes to the source tree for convenience,
such as creating temporary files, without the possibility of interference with
other jobs.