en-US/persistent-network.xml

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<section id="persistent-network">
  <title>Persistent Networks</title>
  <para>The network that you can provision without having to deploy any VMs on it is called a
    persistent network. A persistent network can be part of a VPC or a non-VPC environment.</para>
  <para>When you create other types of network, a network is only a database entry until the first
    VM is created on that network. When the first VM is created, a VLAN ID is assigned and the
    network is provisioned. Also, when the last VM is destroyed, the VLAN ID is released and the
    network is no longer available. With the addition of persistent network, you will have the
    ability to create a network in &PRODUCT; in which physical devices can be deployed without
    having to run any VMs. Additionally, you can deploy physical devices on that network.</para>
  <para>One of the advantages of having a persistent network is that you can create a VPC with a tier
    consisting of only physical devices. For example, you might create a VPC for a three-tier
    application, deploy VMs for Web and Application tier, and use physical machines for the
    Database tier. Another use case is that if you are providing services by using physical
    hardware, you can define the network as persistent and therefore even if all its VMs are
    destroyed the services will not be discontinued.</para>
  <section id="persistent-network-consideration">
    <title>Persistent Network Considerations</title>
    <itemizedlist>
      <listitem>
        <para>Persistent network is designed for isolated networks.</para>
      </listitem>
      <listitem>
        <para>All default network offerings are non-persistent.</para>
      </listitem>
      <listitem>
        <para>A network offering cannot be editable because changing it affects the behavior of the
          existing networks that were created using this network offering.</para>
      </listitem>
      <listitem>
        <para>When you create a guest network, the network offering that you select defines the
          network persistence. This in turn depends on whether persistent network is enabled in the
          selected network offering. </para>
      </listitem>
      <listitem>
        <para>An existing network can be made persistent by changing its network offering to an
          offering that has the Persistent option enabled. While setting this property, even if the
          network has no running VMs, the network is provisioned. </para>
      </listitem>
      <listitem>
        <para>An existing network can be made non-persistent by changing its network offering to an
          offering that has the Persistent option disabled. If the network has no running VMs,
          during the next network garbage collection run the network is shut down.</para>
      </listitem>
      <listitem>
        <para>When the last VM on a network is destroyed, the network garbage collector checks if
          the network offering associated with the network is persistent, and shuts down the network
          only if it is non-persistent.</para>
      </listitem>
    </itemizedlist>
  </section>
  <section id="set-up-persistent-network">
    <title>Creating a Persistent Guest Network</title>
    <para>To create a persistent network, perform the following:</para>
    <orderedlist>
      <listitem>
        <para>Create a network offering with the Persistent option enabled.</para>
        <para condition="admin">See <xref linkend="creating-network-offerings"/>.</para>
        <para condition="install">See the Administration Guide.</para>
      </listitem>
      <listitem>
        <para>Select Network from the left navigation pane.</para>
      </listitem>
      <listitem>
        <para>Select the guest network that you want to offer this network service to.</para>
      </listitem>
      <listitem>
        <para>Click the Edit button.</para>
      </listitem>
      <listitem>
        <para>From the Network Offering drop-down, select the persistent network offering you have
          just created.</para>
      </listitem>
      <listitem>
        <para>Click OK.</para>
      </listitem>
    </orderedlist>
  </section>
</section>