Add option --without-kvm

Some cloud providers (example, AWS EC2 for non-metal instances) do not
support nested virtualization, as well as some hypervisors (example,
VirtualBox prior to 6.x, Hyper-V on AMD). Option `--without-kvm` can
be used to disable hardware acceleration in these scenarios. Otherwise,
user will receive error when trying to start Qemu-based devices.

Commit also: replace `enable_kvm` and `require_kvm` with newer config
options (`enable_hardware_acceleration` and
`require_hardware_acceleration`); and do some code refactors.

One can argue that, instead of prividing option `--without-kvm`, we
should check if system supports KVM and enable/disable hardware
acceleration accordingly. However, there is the case when the
hypervisor supports nested virtualization, but feature is just disabled.
The chosen approach for this case is to keep KVM enabled and let user
known (user will eventually receive an error) so user can fix it.
Otherwise, user might never know and suffer from performance
degradation.

scripts/remote-install.sh

@@ -26,6 +26,7 @@ function help {
   echo "--with-openvpn: Install OpenVPN" >&2
   echo "--with-iou: Install IOU" >&2
   echo "--with-i386-repository: Add the i386 repositories required by IOU if they are not already available on the system. Warning: this will replace your source.list in order to use the official Ubuntu mirror" >&2
+  echo "--without-kvm: Disable KVM, required if system do not support it (limitation in some hypervisors and cloud providers). Warning: only disable KVM if strictly necessary as this will degrade performance" >&2
   echo "--unstable: Use the GNS3 unstable repository"
   echo "--help: This help" >&2
 }
@@ -45,9 +46,10 @@ fi
 USE_VPN=0
 USE_IOU=0
 I386_REPO=0
+DISABLE_KVM=0
 UNSTABLE=0
 
-TEMP=`getopt -o h --long with-openvpn,with-iou,with-i386-repository,unstable,help -n 'gns3-remote-install.sh' -- "$@"`
+TEMP=`getopt -o h --long with-openvpn,with-iou,with-i386-repository,without-kvm,unstable,help -n 'gns3-remote-install.sh' -- "$@"`
 if [ $? != 0 ]
 then
   help
@@ -70,6 +72,10 @@ while true ; do
           I386_REPO=1
           shift
           ;;
+        --without-kvm)
+          DISABLE_KVM=1
+          shift
+          ;;
         --unstable)
           UNSTABLE=1
           shift
@@ -171,7 +177,7 @@ usermod -aG docker gns3
 
 if [ $USE_IOU == 1 ]
 then
-    log "IOU setup"
+    log "Setup IOU"
     dpkg --add-architecture i386
     apt-get update
 
@@ -204,10 +210,16 @@ configs_path = /opt/gns3/configs
 report_errors = True
 
 [Qemu]
-enable_kvm = True
+enable_hardware_acceleration = True
-require_kvm = True
+require_hardware_acceleration = True
 EOFC
 
+if [ $DISABLE_KVM == 1 ]
+then
+    log "Disable KVM support"
+    sed -i 's/hardware_acceleration = True/hardware_acceleration = False/g' /etc/gns3/gns3_server.conf
+fi
+
 chown -R gns3:gns3 /etc/gns3
 chmod -R 700 /etc/gns3
 
@@ -286,18 +298,9 @@ if [ $USE_VPN == 1 ]
 then
 log "Setup VPN"
 
-cat <<EOFSERVER > /etc/gns3/gns3_server.conf
+log "Change GNS3 to listen on VPN interface"
-[Server]
-host = 172.16.253.1
-port = 3080 
-images_path = /opt/gns3/images
-projects_path = /opt/gns3/projects
-report_errors = True
 
-[Qemu]
+sed -i 's/host = 0.0.0.0/host = 172.16.253.1/' /etc/gns3/gns3_server.conf
-enable_kvm = True
-require_kvm = True
-EOFSERVER
 
 log "Install packages for OpenVPN"
 
@@ -329,7 +332,6 @@ echo "And remove this file with rm /etc/update-motd.d/70-openvpn"
 EOFMOTD
 chmod 755 /etc/update-motd.d/70-openvpn
 
-
 mkdir -p /etc/openvpn/
 
 [ -d /dev/net ] || mkdir -p /dev/net
@@ -385,7 +387,7 @@ status openvpn-status-1194.log
 log-append /var/log/openvpn-udp1194.log
 EOFUDP
 
-echo "Setup HTTP server for serving client certificate"
+log "Setup HTTP server for serving client certificate"
 mkdir -p /usr/share/nginx/openvpn/$UUID
 cp /root/client.ovpn /usr/share/nginx/openvpn/$UUID/$HOSTNAME.ovpn
 touch /usr/share/nginx/openvpn/$UUID/index.html
@@ -402,11 +404,13 @@ EOFNGINX
 service nginx stop
 service nginx start
 
-log "Restart OpenVPN"
+log "Restart OpenVPN and GNS3"
 
 set +e
 service openvpn stop
 service openvpn start
+service gns3 stop
+service gns3 start
 
 log "Download http://$MY_IP_ADDR:8003/$UUID/$HOSTNAME.ovpn to setup your OpenVPN client after rebooting the server"