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11.6. Using Multiple Guest Networks

In zones that use advanced networking, additional networks for guest traffic may be added at any time after the initial installation. You can also customize the domain name associated with the network by specifying a DNS suffix for each network.
A VM's networks are defined at VM creation time. A VM cannot add or remove networks after it has been created, although the user can go into the guest and remove the IP address from the NIC on a particular network.
Each VM has just one default network. The virtual router's DHCP reply will set the guest's default gateway as that for the default network. Multiple non-default networks may be added to a guest in addition to the single, required default network. The administrator can control which networks are available as the default network.
Additional networks can either be available to all accounts or be assigned to a specific account. Networks that are available to all accounts are zone-wide. Any user with access to the zone can create a VM with access to that network. These zone-wide networks provide little or no isolation between guests.Networks that are assigned to a specific account provide strong isolation.

11.6.1. Adding an Additional Guest Network

  1. Log in to the CloudStack UI as an administrator or end user.
  2. In the left navigation, choose Network.
  3. Click Add guest network. Provide the following information:
    • Name: The name of the network. This will be user-visible.
    • Display Text: The description of the network. This will be user-visible.
    • Zone. The name of the zone this network applies to. Each zone is a broadcast domain, and therefore each zone has a different IP range for the guest network. The administrator must configure the IP range for each zone.
    • Network offering: If the administrator has configured multiple network offerings, select the one you want to use for this network.
    • Guest Gateway: The gateway that the guests should use.
    • Guest Netmask: The netmask in use on the subnet the guests will use.
  4. Click Create.

11.6.2. Changing the Network Offering on a Guest Network

A user or administrator can change the network offering that is associated with an existing guest network.
  • Log in to the CloudStack UI as an administrator or end user.
  • If you are changing from a network offering that uses the CloudStack virtual router to one that uses external devices as network service providers, you must first stop all the VMs on the network. See Stopping and Starting VMs. Then return here and continue to the next step
  • In the left navigation, choose Network
  • Click the name of the network you want to modify AttachDiskButton.png: button to attach a volume .
  • In Network Offering, choose the new network offering, then click Apply.
  • A prompt appears asking whether you want to keep the existing CIDR. This is to let you know that if you change the network offering, the CIDR will be affected. Choose No to proceed with the change.
  • Wait for the update to complete. Don’t try to restart VMs until after the network change is complete.
  • If you stopped any VMs in step 2, restart them.