+.. _running:
+
+Running VPP
+===========
+
+.. toctree::
+
+Usergroup
+---------
+
+When VPP is installed, a new usergroup *'vpp'* is created. To avoid running the
+VPP CLI (vppctl) as root, add any existing users to the new group that need to
+interact with VPP:
+
+.. code-block:: console
+
+ $ sudo usermod -a -G vpp user1
+
+Update your current session for the group change to take effect:
+
+.. code-block:: console
+
+ $ newgrp vpp
+
+
+Systemd File vpp.service
+------------------------
+
+When the VPP is installed, a systemd service files is also installed. This
+file, vpp.service (Ubuntu: /lib/systemd/system/vpp.service and CentOS:
+/usr/lib/systemd/system/vpp.service), controls how VPP is run as a service. For
+example, whether or not to restart on failure and if so, with how much delay.
+Also, which UIO driver should be loaded and location of the *'startup.conf'*
+file.
+
+.. code-block:: console
+
+ $ cat /usr/lib/systemd/system/vpp.service
+ [Unit]
+ Description=Vector Packet Processing Process
+ After=syslog.target network.target auditd.service
+
+ [Service]
+ ExecStartPre=-/bin/rm -f /dev/shm/db /dev/shm/global_vm /dev/shm/vpe-api
+ ExecStartPre=-/sbin/modprobe uio_pci_generic
+ ExecStart=/usr/bin/vpp -c /etc/vpp/startup.conf
+ Type=simple
+ Restart=on-failure
+ RestartSec=5s
+
+ [Install]
+ WantedBy=multi-user.target
+
+.. note::
+
+ Some older versions of the *'uio_pci_generic'* driver don't bind all
+ the supported NICs properly, so the *'igb_uio'* driver built from DPDK
+ needs to be installed. This file controls which driver is loaded at boot.
+ *'startup.conf'* file controls which driver is used.