.. Licensed to the Apache Software Foundation (ASF) under one
   or more contributor license agreements.  See the NOTICE file
   distributed with this work for additional information#
   regarding copyright ownership.  The ASF licenses this file
   to you under the Apache License, Version 2.0 (the
   "License"); you may not use this file except in compliance
   with the License.  You may obtain a copy of the License at
   http://www.apache.org/licenses/LICENSE-2.0
   Unless required by applicable law or agreed to in writing,
   software distributed under the License is distributed on an
   "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   KIND, either express or implied.  See the License for the
   specific language governing permissions and limitations
   under the License.


Host LXC Installation
---------------------

System Requirements for LXC Hosts
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

LXC requires the Linux kernel cgroups functionality which is available
starting 2.6.24. Although you are not required to run these
distributions, the following are recommended:

-  CentOS / RHEL: 6.3

-  Ubuntu: 12.04(.1)

The main requirement for LXC hypervisors is the libvirt and Qemu
version. No matter what Linux distribution you are using, make sure the
following requirements are met:

-  libvirt: 1.0.0 or higher

-  Qemu/KVM: 1.0 or higher

The default bridge in CloudStack is the Linux native bridge
implementation (bridge module). CloudStack includes an option to work
with OpenVswitch, the requirements are listed below

-  libvirt: 1.0.0 or higher

-  openvswitch: 1.7.1 or higher

In addition, the following hardware requirements apply:

-  Within a single cluster, the hosts must be of the same distribution
   version.

-  All hosts within a cluster must be homogenous. The CPUs must be of
   the same type, count, and feature flags.

-  Must support HVM (Intel-VT or AMD-V enabled)

-  64-bit x86 CPU (more cores results in better performance)

-  4 GB of memory

-  At least 1 NIC

-  When you deploy CloudStack, the hypervisor host must not have any VMs
   already running


LXC Installation Overview
~~~~~~~~~~~~~~~~~~~~~~~~~

LXC does not have any native system VMs, instead KVM will be used to run
system VMs. This means that your host will need to support both LXC and
KVM, thus most of the installation and configuration will be identical
to the KVM installation. The material in this section doesn't duplicate
KVM installation docs. It provides the CloudStack-specific steps that
are needed to prepare a KVM host to work with CloudStack.

.. warning:: 
   Before continuing, make sure that you have applied the latest updates to 
   your host.

.. warning::
   It is NOT recommended to run services on this host not controlled by 
   CloudStack.

The procedure for installing an LXC Host is:

#. Prepare the Operating System

#. Install and configure libvirt

#. Configure Security Policies (AppArmor and SELinux)

#. Install and configure the Agent


Prepare the Operating System
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The OS of the Host must be prepared to host the CloudStack Agent and run
KVM instances.

#. Log in to your OS as root.

#. Check for a fully qualified hostname.

   .. sourcecode:: bash

      $ hostname --fqdn

   This should return a fully qualified hostname such as
   "kvm1.lab.example.org". If it does not, edit /etc/hosts so that it
   does.

#. Make sure that the machine can reach the Internet.

   .. sourcecode:: bash

      $ ping www.cloudstack.org

#. Turn on NTP for time synchronization.

   .. note:: 
      NTP is required to synchronize the clocks of the servers in your
      cloud. Unsynchronized clocks can cause unexpected problems.

   #. Install NTP

      .. sourcecode:: bash

         $ yum install ntp

      .. sourcecode:: bash

         $ apt-get install openntpd

#. Repeat all of these steps on every hypervisor host.


Install and configure the Agent
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To manage LXC instances on the host CloudStack uses a Agent. This Agent
communicates with the Management server and controls all the instances
on the host.

First we start by installing the agent:

In RHEL or CentOS:

.. sourcecode:: bash

   $ yum install cloudstack-agent

In Ubuntu:

.. sourcecode:: bash

   $ apt-get install cloudstack-agent

Next step is to update the Agent configuration setttings. The settings
are in ``/etc/cloudstack/agent/agent.properties``

#. Set the Agent to run in LXC mode:

   .. sourcecode:: bash

      hypervisor.type=lxc

#. Optional: If you would like to use direct networking (instead of the
   default bridge networking), configure these lines:

   .. sourcecode:: bash

      libvirt.vif.driver=com.cloud.hypervisor.kvm.resource.DirectVifDriver

   .. sourcecode:: bash

      network.direct.source.mode=private

   .. sourcecode:: bash

      network.direct.device=eth0

The host is now ready to be added to a cluster. This is covered in a
later section, see :ref:`adding-a-host`. It is
recommended that you continue to read the documentation before adding
the host!


Install and Configure libvirt
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

CloudStack uses libvirt for managing virtual machines. Therefore it is
vital that libvirt is configured correctly. Libvirt is a dependency of
cloudstack-agent and should already be installed.

#. In order to have live migration working libvirt has to listen for
   unsecured TCP connections. We also need to turn off libvirts attempt
   to use Multicast DNS advertising. Both of these settings are in
   ``/etc/libvirt/libvirtd.conf``

   Set the following parameters:

   .. sourcecode:: bash

      listen_tls = 0

   .. sourcecode:: bash

      listen_tcp = 1

   .. sourcecode:: bash

      tcp_port = "16509"

   .. sourcecode:: bash

      auth_tcp = "none"

   .. sourcecode:: bash

      mdns_adv = 0

#. Turning on "listen\_tcp" in libvirtd.conf is not enough, we have to
   change the parameters as well:

   On RHEL or CentOS modify ``/etc/sysconfig/libvirtd``:

   Uncomment the following line:

   .. sourcecode:: bash

      #LIBVIRTD_ARGS="--listen"

   On Ubuntu: modify ``/etc/default/libvirt-bin``

   Add "-l" to the following line

   .. sourcecode:: bash

      libvirtd_opts="-d"

   so it looks like:

   .. sourcecode:: bash

      libvirtd_opts="-d -l"

#. In order to have the VNC Console work we have to make sure it will
   bind on 0.0.0.0. We do this by editing ``/etc/libvirt/qemu.conf``

   Make sure this parameter is set:

   .. sourcecode:: bash

      vnc_listen = "0.0.0.0"

#. Restart libvirt

   In RHEL or CentOS:

   .. sourcecode:: bash

      $ service libvirtd restart

   In Ubuntu:

   .. sourcecode:: bash

      $ service libvirt-bin restart


Configure the Security Policies
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

CloudStack does various things which can be blocked by security
mechanisms like AppArmor and SELinux. These have to be disabled to
ensure the Agent has all the required permissions.

#. Configure SELinux (RHEL and CentOS)

   #. Check to see whether SELinux is installed on your machine. If not,
      you can skip this section.

      In RHEL or CentOS, SELinux is installed and enabled by default.
      You can verify this with:

      .. sourcecode:: bash

         $ rpm -qa | grep selinux

   #. Set the SELINUX variable in ``/etc/selinux/config`` to
      "permissive". This ensures that the permissive setting will be
      maintained after a system reboot.

      In RHEL or CentOS:

      .. sourcecode:: bash

         $ vi /etc/selinux/config

      Change the following line

      .. sourcecode:: bash

         SELINUX=enforcing

      to this

      .. sourcecode:: bash

         SELINUX=permissive

   #. Then set SELinux to permissive starting immediately, without
      requiring a system reboot.

      .. sourcecode:: bash

         $ setenforce permissive

#. Configure Apparmor (Ubuntu)

   #. Check to see whether AppArmor is installed on your machine. If
      not, you can skip this section.

      In Ubuntu AppArmor is installed and enabled by default. You can
      verify this with:

      .. sourcecode:: bash

         $ dpkg --list 'apparmor'

   #. Disable the AppArmor profiles for libvirt

      .. sourcecode:: bash

         $ ln -s /etc/apparmor.d/usr.sbin.libvirtd /etc/apparmor.d/disable/

      .. sourcecode:: bash

         $ ln -s /etc/apparmor.d/usr.lib.libvirt.virt-aa-helper /etc/apparmor.d/disable/

      .. sourcecode:: bash

         $ apparmor_parser -R /etc/apparmor.d/usr.sbin.libvirtd

      .. sourcecode:: bash

         $ apparmor_parser -R /etc/apparmor.d/usr.lib.libvirt.virt-aa-helper


Configure the network bridges
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. warning:: 
   This is a very important section, please make sure you read this thoroughly.

.. note:: 
   This section details how to configure bridges using the native 
   implementation in Linux. Please refer to the next section if you intend to 
   use OpenVswitch

In order to forward traffic to your instances you will need at least two
bridges: *public* and *private*.

By default these bridges are called *cloudbr0* and *cloudbr1*, but you
do have to make sure they are available on each hypervisor.

The most important factor is that you keep the configuration consistent
on all your hypervisors.


Network example
^^^^^^^^^^^^^^^

There are many ways to configure your network. In the Basic networking
mode you should have two (V)LAN's, one for your private network and one
for the public network.

We assume that the hypervisor has one NIC (eth0) with three tagged
VLAN's:

#. VLAN 100 for management of the hypervisor

#. VLAN 200 for public network of the instances (cloudbr0)

#. VLAN 300 for private network of the instances (cloudbr1)

On VLAN 100 we give the Hypervisor the IP-Address 192.168.42.11/24 with
the gateway 192.168.42.1

.. note::
   The Hypervisor and Management server don't have to be in the same subnet!

Configuring the network bridges
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

It depends on the distribution you are using how to configure these,
below you'll find examples for RHEL/CentOS and Ubuntu.

.. note:: 
   The goal is to have two bridges called 'cloudbr0' and 'cloudbr1' after this 
   section. This should be used as a guideline only. The exact configuration 
   will depend on your network layout.


Configure in RHEL or CentOS
'''''''''''''''''''''''''''

The required packages were installed when libvirt was installed, we can
proceed to configuring the network.

First we configure eth0

.. sourcecode:: bash

   $ vi /etc/sysconfig/network-scripts/ifcfg-eth0

Make sure it looks similar to:

.. sourcecode:: bash

   DEVICE=eth0
   HWADDR=00:04:xx:xx:xx:xx
   ONBOOT=yes
   HOTPLUG=no
   BOOTPROTO=none
   TYPE=Ethernet

We now have to configure the three VLAN interfaces:

.. sourcecode:: bash

   $ vi /etc/sysconfig/network-scripts/ifcfg-eth0.100

.. sourcecode:: bash

   DEVICE=eth0.100
   HWADDR=00:04:xx:xx:xx:xx
   ONBOOT=yes
   HOTPLUG=no
   BOOTPROTO=none
   TYPE=Ethernet
   VLAN=yes
   IPADDR=192.168.42.11
   GATEWAY=192.168.42.1
   NETMASK=255.255.255.0

.. sourcecode:: bash

   $ vi /etc/sysconfig/network-scripts/ifcfg-eth0.200

.. sourcecode:: bash

   DEVICE=eth0.200
   HWADDR=00:04:xx:xx:xx:xx
   ONBOOT=yes
   HOTPLUG=no
   BOOTPROTO=none
   TYPE=Ethernet
   VLAN=yes
   BRIDGE=cloudbr0

.. sourcecode:: bash

   $ vi /etc/sysconfig/network-scripts/ifcfg-eth0.300

.. sourcecode:: bash

   DEVICE=eth0.300
   HWADDR=00:04:xx:xx:xx:xx
   ONBOOT=yes
   HOTPLUG=no
   BOOTPROTO=none
   TYPE=Ethernet
   VLAN=yes
   BRIDGE=cloudbr1

Now we have the VLAN interfaces configured we can add the bridges on top
of them.

.. sourcecode:: bash

   $ vi /etc/sysconfig/network-scripts/ifcfg-cloudbr0

Now we just configure it is a plain bridge without an IP-Address

.. sourcecode:: bash

   DEVICE=cloudbr0
   TYPE=Bridge
   ONBOOT=yes
   BOOTPROTO=none
   IPV6INIT=no
   IPV6_AUTOCONF=no
   DELAY=5
   STP=yes

We do the same for cloudbr1

.. sourcecode:: bash

   $ vi /etc/sysconfig/network-scripts/ifcfg-cloudbr1

.. sourcecode:: bash

   DEVICE=cloudbr1
   TYPE=Bridge
   ONBOOT=yes
   BOOTPROTO=none
   IPV6INIT=no
   IPV6_AUTOCONF=no
   DELAY=5
   STP=yes

With this configuration you should be able to restart the network,
although a reboot is recommended to see if everything works properly.

.. warning:: 
   Make sure you have an alternative way like IPMI or ILO to reach the machine 
   in case you made a configuration error and the network stops functioning!


Configure in Ubuntu
'''''''''''''''''''

All the required packages were installed when you installed libvirt, so
we only have to configure the network.

.. sourcecode:: bash

   $ vi /etc/network/interfaces

Modify the interfaces file to look like this:

.. sourcecode:: bash

   auto lo
   iface lo inet loopback

   # The primary network interface
   auto eth0.100
   iface eth0.100 inet static
       address 192.168.42.11
       netmask 255.255.255.240
       gateway 192.168.42.1
       dns-nameservers 8.8.8.8 8.8.4.4
       dns-domain lab.example.org

   # Public network
   auto cloudbr0
   iface cloudbr0 inet manual
       bridge_ports eth0.200
       bridge_fd 5
       bridge_stp off
       bridge_maxwait 1

   # Private network
   auto cloudbr1
   iface cloudbr1 inet manual
       bridge_ports eth0.300
       bridge_fd 5
       bridge_stp off
       bridge_maxwait 1

With this configuration you should be able to restart the network,
although a reboot is recommended to see if everything works properly.

.. warning:: 
   Make sure you have an alternative way like IPMI or ILO to reach the machine 
   in case you made a configuration error and the network stops functioning!


Configuring the firewall
~~~~~~~~~~~~~~~~~~~~~~~~

The hypervisor needs to be able to communicate with other hypervisors
and the management server needs to be able to reach the hypervisor.

In order to do so we have to open the following TCP ports (if you are
using a firewall):

#. 22 (SSH)

#. 1798

#. 16509 (libvirt)

#. 5900 - 6100 (VNC consoles)

#. 49152 - 49216 (libvirt live migration)

It depends on the firewall you are using how to open these ports. Below
you'll find examples how to open these ports in RHEL/CentOS and Ubuntu.


Open ports in RHEL/CentOS
^^^^^^^^^^^^^^^^^^^^^^^^^

RHEL and CentOS use iptables for firewalling the system, you can open
extra ports by executing the following iptable commands:

.. sourcecode:: bash

   $ iptables -I INPUT -p tcp -m tcp --dport 22 -j ACCEPT

.. sourcecode:: bash

   $ iptables -I INPUT -p tcp -m tcp --dport 1798 -j ACCEPT

.. sourcecode:: bash

   $ iptables -I INPUT -p tcp -m tcp --dport 16509 -j ACCEPT

.. sourcecode:: bash

   $ iptables -I INPUT -p tcp -m tcp --dport 5900:6100 -j ACCEPT

.. sourcecode:: bash

   $ iptables -I INPUT -p tcp -m tcp --dport 49152:49216 -j ACCEPT

These iptable settings are not persistent accross reboots, we have to
save them first.

.. sourcecode:: bash

   $ iptables-save > /etc/sysconfig/iptables


Open ports in Ubuntu
^^^^^^^^^^^^^^^^^^^^

The default firewall under Ubuntu is UFW (Uncomplicated FireWall), which
is a Python wrapper around iptables.

To open the required ports, execute the following commands:

.. sourcecode:: bash

   $ ufw allow proto tcp from any to any port 22

.. sourcecode:: bash

   $ ufw allow proto tcp from any to any port 1798

.. sourcecode:: bash

   $ ufw allow proto tcp from any to any port 16509

.. sourcecode:: bash

   $ ufw allow proto tcp from any to any port 5900:6100

.. sourcecode:: bash

   $ ufw allow proto tcp from any to any port 49152:49216

.. note:: 
   By default UFW is not enabled on Ubuntu. Executing these commands with the 
   firewall disabled does not enable the firewall.


Add the host to CloudStack
~~~~~~~~~~~~~~~~~~~~~~~~~~

The host is now ready to be added to a cluster. This is covered in a
later section, see :ref:`adding-a-host`. It is
recommended that you continue to read the documentation before adding
the host!