Failover across GCP subnets using overlay IP - Windows

Last published : Jul 07, 2026
InfoScale clusters let you fail over IPs - and thereby, the application configured for HA - between different subnets in the same zone or in different zones.
The following information is required:
  • The overlay IP address to be used for failover
(The overlay IP address must be defined outside the CIDR block to which the cluster nodes belong.)
  • The device to which the IP should be plumbed
  • The google-api-python-client GCP Python module. For details, see the Bundled Agents Reference Guide - Windows.
The private IP of one subnet cannot be failed over to a different subnet. InfoScale Enterprise provides an overlay IP, which can be used across subnets.
Sample configuration with overlay IP for failover across subnets in the same zone
The following graphic depicts a sample failover configuration across subnets within the same zone using an overlay IP:
image
The sample configuration includes the following elements:
  • A VPC network is configured in Region A of the Google cloud.
  • An application is configured for HA using an InfoScale cluster that comprises two nodes, Node 1 and Node 2, which are VM instances.
Node 1 exists in Subnet 1 and Node 2 exists in Subnet 2.
  • An overlay IP is configured to allow the redirection of IP address traffic to another cluster node that belongs to a different subnet during failover or failback. The overlay IP is configured outside the CIDR block of the VPC network to which the nodes belong.
Sample service group configuration with overlay IP for failover across subnets in the same zone
The following snippet is a service group configuration from a sample VCS configuration file (main.cf):
group app_network_sg (
    SystemList = { cloudvm1 = 0, cloudvm2 = 1 }
    AutoStartList = { cloudvm1, cloudvm2 }
    )

    GoogleIP appsg_GoogleIP (
           OverlayIP = "192.168.9.3"
           MACAddress @cloudvm1 = "42:01:0A:D0:08:06"
           MACAddress @cloudvm2 = "42:01:0A:D0:08:05"
    )

    IP appsg_ip (
           Address = "192.168.9.3"
           SubNetMask = "255.255.252.0"
           MACAddress @cloudvm1 = "42:01:0A:D0:08:06"
           MACAddress @cloudvm2 = "42:01:0A:D0:08:05"
    )

    NIC appsg_nic (
           MACAddress @cloudvm1 = "42:01:0A:D0:08:06"
           MACAddress @cloudvm2 = "42:01:0A:D0:08:05"
    )

appsg_GoogleIP requires appsg_ip
appsg_ip requires appsg_nic
Sample configuration with overlay IP for failover across subnets in different zones
The following graphic depicts a sample failover configuration across subnets in different zones using an overlay IP:
image
Sample service group configuration with overlay IP for failover across subnets in different zones
The following snippet is a service group configuration from a sample VCS configuration file (main.cf):
group app_network_sg (
    SystemList = { cloudvm1 = 0, cloudvm2 = 1 }
    AutoStartList = { cloudvm1, cloudvm2 }
    )

    GoogleIP appsg_GoogleIP (
           OverlayIP = "192.168.9.3"
           MACAddress @cloudvm1 = "42:01:0A:D0:08:06"
           MACAddress @cloudvm2 = "42:01:0A:D0:08:05"
    )

    IP appsg_ip (
           Address = "192.168.9.3"
           SubNetMask = "255.255.252.0"
           MACAddress @cloudvm1 = "42:01:0A:D0:08:06"
           MACAddress @cloudvm2 = "42:01:0A:D0:08:05"
    )

    NIC appsg_nic (
           MACAddress @cloudvm1 = "42:01:0A:D0:08:06"
           MACAddress @cloudvm2 = "42:01:0A:D0:08:05"
    )

appsg_GoogleIP requires appsg_ip
appsg_ip requires appsg_nic