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15.13. Multiple Subnets in Shared Network

CloudStack provides you with the flexibility to add guest IP ranges from different subnets in Basic zones and security groups-enabled Advanced zones. For security groups-enabled Advanced zones, it implies multiple subnets can be added to the same VLAN. With the addition of this feature, you will be able to add IP address ranges from the same subnet or from a different one when IP address are exhausted. This would in turn allows you to employ higher number of subnets and thus reduce the address management overhead. You can delete the IP ranges you have added.

15.13.1. Prerequisites and Guidelines

  • This feature can only be implemented:
    • on IPv4 addresses
    • if virtual router is the DHCP provider
    • on KVM, xenServer, and VMware hypervisors
  • Manually configure the gateway of the new subnet before adding the IP range.
  • CloudStack supports only one gateway for a subnet; overlapping subnets are not currently supported

15.13.2. Adding Multiple Subnets to a Shared Network

  1. Log in to the CloudStack UI as an administrator or end user.
  2. In the left navigation, choose Infrastructure.
  3. On Zones, click View More, then click the zone to which you want to work with..
  4. Click Physical Network.
  5. In the Guest node of the diagram, click Configure.
  6. Click Networks.
  7. Select the networks you want to work with.
  8. Click View IP Ranges.
  9. Click Add IP Range.
    The Add IP Range dialog is displayed, as follows:
    add-ip-range.png: adding an IP range to a network.
  10. Specify the following:
    All the fields are mandatory.
    • Gateway: The gateway for the tier you create. Ensure that the gateway is within the Super CIDR range that you specified while creating the VPC, and is not overlapped with the CIDR of any existing tier within the VPC.
    • Netmask: The netmask for the tier you create.
      For example, if the VPC CIDR is 10.0.0.0/16 and the network tier CIDR is 10.0.1.0/24, the gateway of the tier is 10.0.1.1, and the netmask of the tier is 255.255.255.0.
    • Start IP/ End IP: A range of IP addresses that are accessible from the Internet and will be allocated to guest VMs. Enter the first and last IP addresses that define a range that CloudStack can assign to guest VMs .
  11. Click OK.