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Working with System Virtual Machines
====================================

CloudStack uses several types of system virtual machines to perform
tasks in the cloud. In general CloudStack manages these system VMs and
creates, starts, and stops them as needed based on scale and immediate
needs. However, the administrator should be aware of them and their
roles to assist in debugging issues.


The System VM Template
----------------------

The System VMs come from a single template. The System VM has the
following characteristics:

-  Debian 6.0 ("Squeeze"), 2.6.32 kernel with the latest security
   patches from the Debian security APT repository

-  Has a minimal set of packages installed thereby reducing the attack
   surface

-  32-bit for enhanced performance on Xen/VMWare

-  pvops kernel with Xen PV drivers, KVM virtio drivers, and VMware
   tools for optimum performance on all hypervisors

-  Xen tools inclusion allows performance monitoring

-  Latest versions of HAProxy, iptables, IPsec, and Apache from debian
   repository ensures improved security and speed

-  Latest version of JRE from Sun/Oracle ensures improved security and
   speed


Changing the Default System VM Template
---------------------------------------

CloudStack allows you to change the default 32-bit System VM template to
64-bit one. Using the 64-bit template, upgrade the virtual router to
manage larger number of connection in your network.

#. Based on the hypervisor you use, download the 64-bit template from
   the following location:

   .. cssclass:: table-striped table-bordered table-hover
   
   ==========  ================================================================================================
   Hypervisor  Download Location
   ==========  ================================================================================================
   XenServer   http://download.cloud.com/templates/4.2/64bit/systemvmtemplate64-2013-07-15-master-xen.vhd.bz2
   KVM         http://download.cloud.com/templates/4.2/64bit/systemvmtemplate64-2013-07-15-master-kvm.qcow2.bz2
   ==========  ================================================================================================

#. As an administrator, log in to the CloudStack UI

#. Register the 64 bit template.

   For example: KVM64bitTemplate

#. While registering the template, select Routing.

#. Navigate to Infrastructure > Zone > Settings.

#. Set the name of the 64-bit template, KVM64bitTemplate, in the
   *``router.template.kvm``* global parameter.

   If you are using a XenServer 64-bit template, set the name in the
   *``router.template.xen``* global parameter.

   Any new virtual router created in this Zone automatically picks up
   this template.

#. Restart the Management Server.


Multiple System VM Support for VMware
-------------------------------------

Every CloudStack zone has single System VM for template processing tasks
such as downloading templates, uploading templates, and uploading ISOs.
In a zone where VMware is being used, additional System VMs can be
launched to process VMware-specific tasks such as taking snapshots and
creating private templates. The CloudStack management server launches
additional System VMs for VMware-specific tasks as the load increases.
The management server monitors and weights all commands sent to these
System VMs and performs dynamic load balancing and scaling-up of more
System VMs.


Console Proxy
-------------

The Console Proxy is a type of System Virtual Machine that has a role in
presenting a console view via the web UI. It connects the user’s browser
to the VNC port made available via the hypervisor for the console of the
guest. Both the administrator and end user web UIs offer a console
connection.

Clicking a console icon brings up a new window. The AJAX code downloaded
into that window refers to the public IP address of a console proxy VM.
There is exactly one public IP address allocated per console proxy VM.
The AJAX application connects to this IP. The console proxy then proxies
the connection to the VNC port for the requested VM on the Host hosting
the guest.

.. note:: 
   The hypervisors will have many ports assigned to VNC usage so that 
   multiple VNC sessions can occur simultaneously.

There is never any traffic to the guest virtual IP, and there is no need
to enable VNC within the guest.

The console proxy VM will periodically report its active session count
to the Management Server. The default reporting interval is five
seconds. This can be changed through standard Management Server
configuration with the parameter consoleproxy.loadscan.interval.

Assignment of guest VM to console proxy is determined by first
determining if the guest VM has a previous session associated with a
console proxy. If it does, the Management Server will assign the guest
VM to the target Console Proxy VM regardless of the load on the proxy
VM. Failing that, the first available running Console Proxy VM that has
the capacity to handle new sessions is used.

Console proxies can be restarted by administrators but this will
interrupt existing console sessions for users.


Using a SSL Certificate for the Console Proxy
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. note::
   In the past CloudStack used the ``realhostip.com`` dynamic  DNS 
   resolution service. As this service will be shut down as of  
   June 30th, 2014, CloudStack has stopped using the service as of 
   version 4.3.

By default, the console viewing functionality uses plaintext HTTP. In 
any production environment, the console proxy connection should be
encrypted via SSL at the mininum.

A CloudStack administrator has 2 ways to secure the console proxy
communication with SSL:

-  Set up a SSL wild-card certificate and domain name resolution
   
-  Set up SSL certificate for specific FQDN and configure load-balancer


Changing the Console Proxy SSL Certificate and Domain
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The administrator can configure SSL encryption  by selecting a domain 
and uploading a new SSL certificate and private key. The domain must 
run a DNS service that is capable of resolving queries for addresses 
of the form aaa-bbb-ccc-ddd.your.domain to an IPv4 IP address in the
form aaa.bbb.ccc.ddd, for example, 202.8.44.1. To change the console 
proxy domain, SSL certificate, and private key:

#. Set up dynamic name resolution or populate all possible DNS names in
   your public IP range into your existing DNS server with the format
   aaa-bbb-ccc-ddd.consoleproxy.company.com -> aaa.bbb.ccc.ddd.

   .. note::
      In these steps you will notice *consoleproxy.company.com* -For 
      security best practices, we recommend creating a wildcard SSL 
      certificate on a separate subdomain so in the event that the 
      certificate is compromised, a malicious user cannot impersonate 
      a company.com domain.

#. Generate the private key and certificate signing request (CSR). When
   you are using openssl to generate private/public key pairs and CSRs,
   for the private key that you are going to paste into the CloudStack
   UI, be sure to convert it into PKCS#8 format.

   #. Generate a new 2048-bit private key

      .. code:: bash

         openssl genrsa -des3 -out yourprivate.key 2048

   #. Generate a new certificate CSR. Ensure the creation of a wildcard 
      certificate, eg ``*.consoleproxy.company.com``

      .. code:: bash

         openssl req -new -key yourprivate.key -out yourcertificate.csr

   #. Head to the website of your favorite trusted Certificate
      Authority, purchase an SSL certificate, and submit the CSR. You
      should receive a valid certificate in return

   #. Convert your private key format into PKCS#8 encrypted format.

      .. code:: bash

         openssl pkcs8 -topk8 -in yourprivate.key -out yourprivate.pkcs8.encrypted.key

   #. Convert your PKCS#8 encrypted private key into the PKCS#8 format
      that is compliant with CloudStack

      .. code:: bash

         openssl pkcs8 -in yourprivate.pkcs8.encrypted.key -out yourprivate.pkcs8.key

#. In the Update SSL Certificate screen of the CloudStack UI, paste the
   following:

   -  The certificate you've just generated.

   -  The private key you've just generated.

   -  The desired domain name, prefixed with ``*.``; for example, ``*.consoleproxy.company.com``

     |update-ssl.png|

#. This stops all currently running console proxy VMs, then restarts
   them with the new certificate and key. Users might notice a brief
   interruption in console availability.

The Management Server generates URLs of the form
"aaa-bbb-ccc-ddd.consoleproxy.company.com" after this change is made. 
The new console requests will be served with the new DNS domain name, 
certificate, and key.


Load-balancing Console Proxies
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
An alternative to using dynamic DNS or creating a range of DNS entries 
as described in the last section would be to create a SSL certificate
for a specific domain name, configure CloudStack to use that particular
FQDN, and then configure a load balancer to load balance the console
proxy's IP address behind the FQDN. As the functionality for this is 
still new, please see 
https://cwiki.apache.org/confluence/display/CLOUDSTACK/Realhost+IP+changes
for more details.


Virtual Router
--------------

The virtual router is a type of System Virtual Machine. The virtual
router is one of the most frequently used service providers in
CloudStack. The end user has no direct access to the virtual router.
Users can ping the virtual router and take actions that affect it (such
as setting up port forwarding), but users do not have SSH access into
the virtual router.

There is no mechanism for the administrator to log in to the virtual
router. Virtual routers can be restarted by administrators, but this
will interrupt public network access and other services for end users. A
basic test in debugging networking issues is to attempt to ping the
virtual router from a guest VM. Some of the characteristics of the
virtual router are determined by its associated system service offering.


Configuring the Virtual Router
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can set the following:

-  IP range

-  Supported network services

-  Default domain name for the network serviced by the virtual router

-  Gateway IP address

-  How often CloudStack fetches network usage statistics from CloudStack
   virtual routers. If you want to collect traffic metering data from
   the virtual router, set the global configuration parameter
   router.stats.interval. If you are not using the virtual router to
   gather network usage statistics, set it to 0.


Upgrading a Virtual Router with System Service Offerings
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

When CloudStack creates a virtual router, it uses default settings which
are defined in a default system service offering. See `“System Service 
Offerings” <#system-service-offerings>`_. All the
virtual routers in a single guest network use the same system service
offering. You can upgrade the capabilities of the virtual router by
creating and applying a custom system service offering.

#. Define your custom system service offering. 
   See `“Creating a New System Service Offering” 
   <#creating-a-new-system-service-offering>`_. 
   In System VM Type, choose Domain Router.

#. Associate the system service offering with a network offering. See
   `“Creating a New Network Offering” 
   <networking.html#creating-a-new-network-offering>`_.

#. Apply the network offering to the network where you want the virtual
   routers to use the new system service offering. If this is a new
   network, follow the steps in Adding an Additional Guest Network on
   page 66. To change the service offering for existing virtual routers,
   follow the steps in `“Changing the Network Offering on a Guest Network” 
   <networking2.html#changing-the-network-offering-on-a-guest-network>`_.


Best Practices for Virtual Routers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

-  WARNING: Restarting a virtual router from a hypervisor console
   deletes all the iptables rules. To work around this issue, stop the
   virtual router and start it from the CloudStack UI.

-  .. warning:: 
      Do not use the destroyRouter API when only one router is available 
      in the network, because restartNetwork API with the cleanup=false 
      parameter can't recreate it later. If you want to destroy and 
      recreate the single router available in the network, use the 
      restartNetwork API with the cleanup=true parameter.


Service Monitoring Tool for Virtual Router
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Various services running on the CloudStack virtual routers can be 
monitored by using a Service Monitoring tool. The tool ensures that
services are successfully running until CloudStack deliberately disables 
them. If a service goes down, the tool automatically restarts the 
service, and if that does not help bringing up the service, an alert as 
well as an event is generated indicating the failure. A new global 
parameter, ``network.router.enableservicemonitoring``, has been 
introduced to control this feature. The default value is false, implies, 
monitoring is disabled. When you enable, ensure that the Management 
Server and the router are restarted.

Monitoring tool can help to start a VR service, which is crashed due to
an unexpected reason. For example:

-  The services crashed due to defects in the source code.

-  The services that are terminated by the OS when memory or CPU is not
   sufficiently available for the service.

.. note:: 
   Only those services with daemons are monitored. The services that are 
   failed due to errors in the service/daemon configuration file cannot 
   be restarted by the Monitoring tool. VPC networks are not supported.

The following services are monitored in a VR:

-  DNS

-  HA Proxy

-  SSH

-  Apache Web Server

The following networks are supported:

-  Isolated Networks

-  Shared Networks in both Advanced and Basic zone

   .. note:: VPC networks are not supported

This feature is supported on the following hypervisors: XenServer,
VMware, and KVM.


Enhanced Upgrade for Virtual Routers
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Upgrading VR is made flexible. The CloudStack administrators will be
able to control the sequence of the VR upgrades. The sequencing is based
on Infrastructure hierarchy, such as by Cluster, Pod, or Zone, and
Administrative (Account) hierarchy, such as by Tenant or Domain. As an
administrator, you can also determine when a particular customer
service, such as VR, is upgraded within a specified upgrade interval.
Upgrade operation is enhanced to increase the upgrade speed by allowing
as many upgrade operations in parallel as possible.

During the entire duration of the upgrade, users cannot launch new
services or make changes to an existing service.

Additionally, using multiple versions of VRs in a single instance is
supported. In the Details tab of a VR, you can view the version and
whether it requires upgrade. During the Management Server upgrade,
CloudStack checks whether VR is at the latest version before performing
any operation on the VR. To support this, a new global parameter,
*``router.version.check``*, has been added. This parameter is set to
true by default, which implies minimum required version is checked
before performing any operation. No operation is performed if the VR is
not at the required version. Services of the older version VR continue
to be available, but no further operations can be performed on the VR
until it is upgraded to the latest version. This will be a transient
state until the VR is upgraded. This will ensure that the availability
of VR services and VR state is not impacted due to the Management Server
upgrade.

The following service will be available even if the VR is not upgraded.
However, no changes for any of the services can be sent to the VR, until
it is upgraded:

-  SecurityGroup

-  UserData

-  DHCP

-  DNS

-  LB

-  Port Forwarding

-  VPN

-  Static NAT

-  Source NAT

-  Firewall

-  Gateway

-  NetworkACL


Supported Virtual Routers
^^^^^^^^^^^^^^^^^^^^^^^^^

-  VR

-  VPC VR

-  Redundant VR


Upgrading Virtual Routers
^^^^^^^^^^^^^^^^^^^^^^^^^

#. Download the latest System VM template.

#. Download the latest System VM to all the primary storage pools.

#. Upgrade the Management Server.

#. Upgrade CPVM and SSVM either from the UI or by using the following
   script:

   .. code:: bash

      # cloudstack-sysvmadm -d <IP address> -u cloud -p -s

   Even when the VRs are still on older versions, existing services will
   continue to be available to the VMs. The Management Server cannot
   perform any operations on the VRs until they are upgraded.

#. Selectively upgrade the VRs:

   #. Log in to the CloudStack UI as the root administrator.

   #. In the left navigation, choose Infrastructure.

   #. On Virtual Routers, click View More.

      All the VRs are listed in the Virtual Routers page.

   #. In Select View drop-down, select desired grouping based on your
      requirement.

      You can use either of the following:

      -  Group by zone

      -  Group by pod

      -  Group by cluster

      -  Group by account

   #. Click the group which has the VRs to be upgraded.

      For example, if you have selected Group by zone, select the name
      of the desired zone.

   #. Click the Upgrade button to upgrade all the VRs. |vr-upgrade.png|

   #. Click OK to confirm.


Secondary Storage VM
--------------------

In addition to the hosts, CloudStack’s Secondary Storage VM mounts and
writes to secondary storage.

Submissions to secondary storage go through the Secondary Storage VM.
The Secondary Storage VM can retrieve templates and ISO images from URLs
using a variety of protocols.

The secondary storage VM provides a background task that takes care of a
variety of secondary storage activities: downloading a new template to a
Zone, copying templates between Zones, and snapshot backups.

The administrator can log in to the secondary storage VM if needed.


.. |update-ssl.png| image:: _static/images/update-ssl.png
   :alt: Updating Console Proxy SSL Certificate
.. |vr-upgrade.png| image:: _static/images/vr-upgrade.png
   :alt: Button to upgrade VR to use the new template.