Cluster Server 7.3.1 Bundled Agents Reference Guide - Linux

Last Published:
Product(s): InfoScale & Storage Foundation (7.3.1)
Platform: Linux
  1. Introducing Bundled agents
    1.  
      About Bundled agents
    2.  
      Resources and their attributes
    3.  
      Modifying agents and their resources
    4.  
      Attributes
    5.  
      IMF-aware agents
    6.  
      Enabling debug log messages
    7.  
      VCS support for multi-pathing solutions
  2. Storage agents
    1.  
      About the storage agents
    2. DiskGroup agent
      1.  
        IMF awareness
      2.  
        Dependencies for DiskGroup agent
      3.  
        Agent functions for DiskGroup agent
      4.  
        State definitions for DiskGroup agent
      5.  
        Attributes for DiskGroup agent
      6.  
        Resource type definition
      7. Notes for DiskGroup agent
        1.  
          High availability fire drill
        2.  
          Using volume sets
        3.  
          Setting the noautoimport flag for a disk group
        4.  
          Configuring the Fiber Channel adapter
        5.  
          Using the DiskGroup agent with IMF
      8. Sample configurations for DiskGroup agent
        1.  
          DiskGroup resource configuration
      9.  
        Debug log levels for DiskGroup agent
    3. DiskGroupSnap agent
      1.  
        Dependencies for DiskGroupSnap agent
      2.  
        Agent functions for DiskGroupSnap agent
      3.  
        State definitions for DiskGroupSnap agent
      4.  
        Attributes for DiskGroupSnap agent
      5. Notes for DiskGroupSnap agent
        1.  
          Fire drill configuration after upgrading VCS
        2.  
          Configuring the SystemZones attribute for the fire drill service group
        3.  
          Configuring the FireDrill service group
        4.  
          Adding the ReuseMntPt attribute to the ArgList attribute for the Mount agent type
        5.  
          Configuration considerations
        6.  
          Agent limitations
      6.  
        Resource type definition for DiskGroupSnap agent
      7. Sample configurations for DiskGroupSnap agent
        1.  
          Typical main.cf configuration for DiskGroupSnap agent
        2.  
          Sample main.cf of DiskGroupSnap with Oracle resource
      8.  
        Debug log levels for DiskGroupSnap agent
    4. Volume agent
      1.  
        Dependencies for Volume agent
      2.  
        Agent functions for Volume agent
      3.  
        State definitions for Volume agent
      4.  
        Attributes for Volume agent
      5.  
        Resource type definition for Volume agent
      6.  
        Sample configuration for Volume agent
      7.  
        Debug log levels for Volume agent
    5. VolumeSet agent
      1.  
        Dependencies for VolumeSet agent
      2.  
        Agent functions for VolumeSet agent
      3.  
        State definitions for VolumeSet agent
      4.  
        Attributes for VolumeSet agent
      5.  
        Resource type definition for VolumeSet agent
      6. Sample configurations for VolumeSet agent
        1.  
          A configured VolumeSet that is dependent on a DiskGroup resource
      7.  
        Agent notes for VolumeSet agent
      8.  
        Inaccessible volumes prevent the VolumeSet agent from coming online
      9.  
        Debug log levels for VolumeSet agent
    6. LVMLogicalVolume agent
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definition
      6.  
        Sample configuration
      7.  
        Debug log levels
    7. LVMVolumeGroup agent
      1.  
        Dependencies for LVMVolumeGroup agent
      2.  
        Agent functions for LVMVolumeGroup agent
      3.  
        State definitions for LVMVolumeGroup agent
      4.  
        Attributes for LVMVolumeGroup agent
      5.  
        Resource type definition for LVMVolumeGroup agent
      6.  
        LVMVolumeGroup agent notes
      7.  
        Enabling volume group activation protection for Dynamic Multi-Pathing
      8.  
        Notes for volume group activation protection
      9. Sample configurations for LVMVolumeGroup agent
        1.  
          Linux configuration 1
        2.  
          Linux Configuration 2
      10.  
        Debug log levels for LVMVolumeGroup agent
    8. Mount agent
      1.  
        IMF awareness
      2.  
        Dependencies for Mount agent
      3.  
        Agent functions for Mount agent
      4.  
        State definitions for Mount agent
      5.  
        Attributes for Mount agent
      6.  
        Resource type definition for Mount agent
      7.  
        Notes for Mount agent
      8.  
        Support for spaces in directory names
      9.  
        Support for multiple bindfs
      10.  
        High availability fire drill
      11.  
        VxFS file system lock
      12.  
        IMF usage notes
      13.  
        Enabling Level two monitoring for the Mount agent
      14.  
        RHEL 7: NFS file system version
      15.  
        RHEL 7: Configuring bind mounts
      16.  
        Support for Amazon EFS
      17. Sample configurations for Mount agent
        1.  
          Basic configuration for Mount agent
        2.  
          VxFS mount lock example for Mount agent
        3.  
          NFS mount example for Mount agent
        4.  
          EFS mount example for Mount agent
      18.  
        Debug log levels for Mount agent
    9. VMwareDisks agent
      1.  
        Agent functions
      2.  
        State definitions
      3.  
        Attributes
      4.  
        Resource type definition
      5.  
        Sample configurations
    10. SFCache agent
      1.  
        Resource dependency
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definition
      6. Notes for SFCache agent
        1.  
          Configuring SFCache resource with CVM/CFS
      7.  
        Debug log levels
    11. AWS EBSVol agent
      1.  
        Prerequisites
      2.  
        Dependencies
      3.  
        Agent functions
      4.  
        State definitions
      5.  
        Attributes
      6.  
        Resource type definition
      7.  
        Sample configuration
      8.  
        Debug log levels
    12. AzureDisk agent
      1.  
        Prerequisites
      2.  
        Dependencies
      3.  
        Agent functions
      4.  
        State definitions
      5.  
        Attributes
      6.  
        Resource type definition
      7.  
        Sample configuration
      8.  
        Debug log levels
  3. Network agents
    1. About the network agents
      1. Agent comparisons
        1.  
          IP and NIC agents
        2.  
          IPMultiNIC and MultiNICA agents
        3.  
          802.1Q trunking
    2. IP agent
      1.  
        High availability fire drill for IP agent
      2.  
        Dependencies for IP agent
      3.  
        Agent functions for IP agent
      4.  
        State definitions for IP agent
      5.  
        Attributes for IP agent
      6.  
        Resource type definition for IP agent
      7. Sample configurations for IP agent
        1.  
          IPv4 Configuration
        2.  
          IPv6 Configuration
      8.  
        Debug log levels for IP agent
    3. NIC agent
      1.  
        Dependencies for NIC agent
      2.  
        Bonded network interfaces for NIC agent
      3.  
        Agent functions for NIC agent
      4.  
        State definitions for NIC agent
      5.  
        Attributes for NIC agent
      6.  
        Resource type definition for NIC agent
      7. Notes for the NIC agent
        1.  
          Monitoring bonded NICs for NIC agent
        2.  
          Setting Mii and miimon for NIC agent
        3.  
          High availability fire drill for NIC agent
      8.  
        Case 1
      9.  
        Case 2
      10.  
        Case 3
      11. Sample configurations for NIC agent
        1.  
          Configuration for using Mii for NIC agent
        2.  
          Configuration for using network hosts for NIC agent
        3.  
          IPv6 configuration for NIC agent
      12.  
        Debug log levels for NIC agent
    4. IPMultiNIC agent
      1.  
        Dependencies for IPMultiNIC agent
      2.  
        Agent functions for IPMultiNIC agent
      3.  
        State definitions for IPMultiNIC agent
      4.  
        Attributes for IPMultiNIC agent
      5.  
        Resource type definition for IPMultiNIC agent
      6. Sample configuration: IPMultiNIC and MultiNICA
        1.  
          IPv4 configuration for IPMultiNIC agent
        2.  
          IPv6 configuration for IPMultiNIC agent
        3.  
          Mixed mode configuration - IPv4 and IPv6 for IPMultiNIC agent
      7.  
        Debug log levels
    5. MultiNICA agent
      1.  
        Dependencies for MultiNICA agent
      2. IP Conservation Mode (ICM) for MultiNICA agent
        1.  
          Configuration for MultiNICA agent
        2.  
          Operation for MultiNICA agent
      3. Performance Mode (PM) for MultiNICA agent
        1.  
          Configuration for MultiNICA agent
        2.  
          Operation for MultiNICA agent
      4.  
        Agent function for MultiNICA agent
      5.  
        Attributes for MultiNICA agent
      6.  
        Resource type definition for MultiNICA agent
      7. Sample configurations for MultiNICA agent
        1.  
          MultiNICA and IPMultiNIC Performance Mode configuration
        2.  
          MultiNICA and IPMultiNIC IP Conservation Mode Configuration
      8.  
        IPv6 configuration for MultiNICA agent
      9.  
        Mixed mode configuration - IPv4 and IPv6 for MultiNICA agent
      10.  
        Debug log levels for MultiNICA agent
    6. DNS agent
      1.  
        Dependencies for DNS agent
      2.  
        Agent functions for DNS agent
      3.  
        State definitions for DNS agent
      4.  
        Attributes for DNS agent
      5.  
        Resource type definition for DNS agent
      6. Agent notes for DNS agent
        1. About using the VCS DNS agent on UNIX with a secure Windows DNS server
          1.  
            Software requirement for DNS agent
          2.  
            Configuration requirement for DNS agent
        2.  
          High availability fire drill for DNS agent
        3.  
          Monitor scenarios for DNS agent
        4.  
          Sample Web server configuration for DNS agent
        5.  
          Secure DNS update for BIND 9 for DNS agent
        6.  
          Setting up secure updates using TSIG keys for BIND 9 for DNS agent
      7. Sample configurations for DNS agent
        1.  
          Basic IPv6 configuration for DNS agent
        2.  
          IPv6 CNAME sample configuration for DNS agent
        3.  
          IPv4 A sample configuration for DNS agent
      8.  
        Debug log levels for DNS agent
    7. AWSIP agent
      1.  
        Prerequisites
      2.  
        Dependencies
      3.  
        Agent functions
      4.  
        State definitions
      5.  
        Attributes
      6.  
        Resource type definition
      7.  
        Samples configurations
    8. AWSRoute53 agent
      1.  
        Prerequisites
      2.  
        Dependencies
      3.  
        Agent functions
      4.  
        State definitions
      5.  
        Attributes
      6.  
        Resource type definition
      7.  
        Sample configuration
    9. AzureIP agent
      1.  
        Prerequisites
      2.  
        Dependencies
      3.  
        Agent functions
      4.  
        State definitions
      5.  
        Attributes
      6.  
        Resource type definition
      7.  
        Sample configuration
      8.  
        Debug log levels
    10. AzureDNSZone agent
      1.  
        Prerequisites
      2.  
        Dependencies
      3.  
        Agent functions
      4.  
        State definitions
      5.  
        Attributes
      6.  
        Resource type definition
      7.  
        Samples configurations
      8.  
        Delegating a domain to Azure DNS
  4. File share agents
    1.  
      About the file service agents
    2. NFS agent
      1.  
        Dependencies for NFS agent
      2.  
        Agent functions for NFS agent
      3.  
        State definitions for NFS agent
      4.  
        Attributes for NFS agent
      5.  
        Resource type definition for NFS agent
      6. Notes for NFS agent
        1.  
          Prerequisites for NFS lock recovery
        2.  
          Using NFSv4
      7.  
        Sample configurations for NFS agent
      8.  
        Debug log levels for NFS agent
    3. NFSRestart agent
      1.  
        Dependencies for NFSRestart agent
      2.  
        Agent functions for NFSRestart agent
      3.  
        State definitions
      4.  
        Attributes for NFSRestart agent
      5.  
        Resource type definition for NFSRestart agent
      6. Notes for NFSRestart agent
        1.  
          About high availability fire drill
        2.  
          Providing a fully qualified host name
      7. Sample configurations for NFSRestart agent
        1.  
          Basic agent configurations
      8.  
        Debug log levels for NFSRestart agent
    4. Share agent
      1.  
        Dependencies for Share agent
      2.  
        Agent functions for Share agent
      3.  
        State definitions for Share agent
      4.  
        Attributes for Share agent
      5.  
        Resource type definition for Share agent
      6. Notes for Share agent
        1.  
          Support for spaces in directory names
        2.  
          High availability fire drill
        3.  
          About entering an IP address in the Client attribute
      7.  
        Sample configurations for Share agent
      8.  
        Debug log levels for Share agent
    5. About the Samba agents
      1.  
        The Samba agents
      2.  
        Before using the Samba agents
      3.  
        Supported versions for Samba agents
      4. Notes for configuring the Samba agents
        1.  
          Enabling VCS to detect services started and stopped by smb
        2.  
          Configuring multiple SambaServer resources
        3.  
          Configuring Samba for non-standard configuration files or non-standard lock directories
    6. SambaServer agent
      1.  
        Dependencies for SambaServer agent
      2.  
        Agent functions for SambaServer agent
      3.  
        State definitions for SambaServer agent
      4.  
        Attributes for SambaServer agent
      5.  
        Resource type definitions for SambaServer agent
      6.  
        Sample configurations for SambaServer agent
      7.  
        Debug log levels for SambaServer agent
    7. SambaShare agent
      1.  
        Dependencies for SambaShare agent
      2.  
        Agent functions for SambaShare agent
      3.  
        State definitions for SambaShare agent
      4.  
        Attributes for SambaShare agent
      5.  
        Resource type definition for SambaShare agent
      6.  
        Sample configuration for SambaShare agent
      7.  
        Debug log levels for SambaShare agent
    8. NetBios agent
      1.  
        Dependencies for NetBios agent
      2.  
        Agent functions for NetBios agent
      3.  
        State definitions for NetBios agent
      4.  
        Attributes for NetBios agent
      5.  
        Resource type definition for NetBios agent
      6.  
        Sample configuration for NetBios agent
      7.  
        Debug log levels for NetBios agent
  5. Service and application agents
    1.  
      About the services and applications agents
    2. Apache HTTP server agent
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definition
      6. Apache HTTP server notes
        1.  
          Tasks to perform before you use the Apache HTTP server agent
        2.  
          About detecting application failure
        3.  
          About bringing an Apache HTTP server online outside of VCS control
        4.  
          About high Availability fire drill
        5.  
          Using Apache agent with IMF
      7. Sample configurations
        1.  
          Running two instances of httpd for Linux
        2.  
          Sample main.cf file
        3.  
          Basic IPv6 configuration
        4.  
          Sample output of the amfstat command
      8.  
        Debug log level
    3. Application agent
      1.  
        IMF awareness
      2.  
        High availability fire drill for Application agent
      3.  
        Dependencies for Application agent
      4.  
        Agent functions
      5.  
        State definitions for Application agent
      6.  
        Attributes for Application agent on Linux
      7.  
        Resource type definition for Application agent
      8. Notes for Application agent
        1.  
          Using Application agent with IMF
        2.  
          Level two monitoring through MonitorProgram
        3.  
          Using Application agent with ProPCV
        4.  
          Requirement for programs
        5.  
          Requirement for default profile
        6.  
          Application monitoring inside Docker container
        7.  
          Using the hadockersetup utility
        8.  
          Requirement for systemd support
      9. Sample configurations for Application agent
        1.  
          Configuration 1 for Application agent
        2.  
          Configuration 2 for Application agent
        3.  
          Configuration 3 for Application agent
        4.  
          Configuration 4 for Application agent
        5.  
          Configuration 5 for Application agent
      10.  
        Debug log levels for Application agent
    4. CoordPoint agent
      1.  
        Coordination Point server as a coordination point
      2.  
        SCSI-3 based disk as a coordination point
      3.  
        Dependencies
      4.  
        Agent functions
      5.  
        State definitions
      6.  
        Attributes
      7.  
        Resource type definition
      8. Notes for the CoordPoint agent
        1.  
          CoordPoint agent I/O fencing reporting activities
        2.  
          AutoStartList attribute
        3.  
          Detailed monitoring for the Coordpoint resource
        4.  
          The ActionOnCoordPointFault attribute set to RefreshRegistrations
      9.  
        Sample configuration
      10.  
        Debug log levels
    5. KVMGuest agent
      1.  
        Dependencies for KVMGuest agent
      2.  
        Agent functions for KVMGuest agent
      3.  
        State definitions for KVMGuest agent
      4.  
        Attributes for KVMGuest agent
      5.  
        Resource type definition for KVMGuest agent
      6. Notes for KVMGuest agent
        1.  
          Support for guests created on RHEL 6, RHEL 7 (KVM environment), and SuSE Enterprise Linux 11 SP2 and SP3
        2.  
          Storage and network configurations
        3.  
          Guest live migration
        4.  
          Managing virtual machines in RHEV environment
        5.  
          Managing ISO image in SuSE KVM
        6.  
          Using VCS to migrate virtual machines
        7.  
          Configuring the KVMGuest agent for DR in a global cluster setup
        8.  
          Configuring a non-admin user for RHEV-M that is using AD-based domain
        9.  
          Virtual machine failover if host crashes
        10.  
          KVMGuest agent requires curl and xpath commands in RHEV environment
        11.  
          RHEV environment: If a node on which the VM is running panics or is forcefully shutdown, VCS is unable to start the VM on another node
      7. Sample configurations for KVMGuest environment
        1.  
          Sample Configuration 1
        2.  
          Sample Configuration 2
        3.  
          Sample Configuration 3
      8. Sample configurations for RHEV environment
        1.  
          Sample Configuration 1
        2.  
          Sample Configuration 2
        3.  
          Sample Configuration 3
      9.  
        Sample Configuration for SuSE KVM
      10.  
        Debug log levels for KVMGuest agent
    6. Process agent
      1.  
        IMF awareness
      2.  
        High availability fire drill for Process agent
      3.  
        Dependencies for Process agent
      4.  
        Agent functions for Process agent
      5.  
        State definitions for Process agent
      6.  
        Attributes for Process agent
      7.  
        Resource type definition for Process agent
      8. Usage notes for Process agent
        1.  
          Prerequisites for processes
      9. Sample configurations for Process agent
        1.  
          Configuration for Process agent
      10.  
        Debug log levels for Process agent
    7. ProcessOnOnly agent
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definition
      6. ProcessOnOnly agent usage notes
        1.  
          Requirement for programs
      7.  
        Sample configurations
      8.  
        Debug log levels
    8. AzureAuth agent
      1.  
        Prerequisites
      2.  
        Dependencies
      3.  
        Agent functions
      4.  
        State definitions
      5.  
        Attributes
      6.  
        Resource type definition
      7.  
        Sample configuration
      8.  
        Obtaining the authentication keys
  6. Infrastructure and support agents
    1.  
      About the infrastructure and support agents
    2. NotifierMngr agent
      1.  
        Dependency
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definition
      6. Sample configuration
        1.  
          Configuration
      7.  
        Debug log levels
    3. Proxy agent
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        Attributes
      4.  
        Resource type definition
      5. Sample configurations
        1.  
          Configuration 1
        2.  
          Configuration 2
        3.  
          Configuration 3
      6.  
        Debug log levels
    4. Phantom agent
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        Resource type definition
      4. Sample configurations
        1.  
          Configuration 1
        2.  
          Configuration 2
    5. RemoteGroup agent
      1.  
        Dependency
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definition
      6.  
        Debug log levels
  7. Testing agents
    1.  
      About the testing agents
    2. ElifNone agent
      1.  
        Dependencies for ElifNone agent
      2.  
        Agent function for ElifNone agent
      3.  
        State definitions for ElifNone agent
      4.  
        Attributes for ElifNone agent
      5.  
        Resource type definition for ElifNone agent
      6.  
        Sample configuration for ElifNone agent
      7.  
        Debug log levels for ElifNone agent
    3. FileNone agent
      1.  
        Dependencies for FileNone agent
      2.  
        Agent functions for FileNone agent
      3.  
        State definitions for FileNone agent
      4.  
        Attribute for FileNone agent
      5.  
        Resource type definition for FileNone agent
      6.  
        Sample configuration for FileNone agent
      7.  
        Debug log levels for FileNone agent
    4. FileOnOff agent
      1.  
        Dependencies for FileOnOff agent
      2.  
        Agent functions for FileOnOff agent
      3.  
        State definitions for FileOnOff agent
      4.  
        Attribute for FileOnOff agent
      5.  
        Resource type definition for FileOnOff agent
      6.  
        Sample configuration for FileOnOff agent
      7.  
        Debug log levels for FileOnOff agent
    5. FileOnOnly agent
      1.  
        Dependencies for FileOnOnly agent
      2.  
        Agent functions for FileOnOnly agent
      3.  
        State definitions for FileOnOnly agent
      4.  
        Attribute for FileOnOnly agent
      5.  
        Resource type definition for FileOnOnly agent
      6.  
        Sample configuration for FileOnOnly agent
      7.  
        Debug log levels for FileOnOnly agent
  8. Replication agents
    1.  
      About the replication agents
    2. RVG agent
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definitions
      6.  
        Sample configurations
    3. RVGPrimary agent
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definitions
      6.  
        Sample configurations
    4. RVGSnapshot
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definitions
      6.  
        Sample configurations
    5. RVGShared agent
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definitions
      6.  
        Sample configurations
    6. RVGLogowner agent
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definitions
      6.  
        RVGLogowner agent notes
      7.  
        Sample configurations
    7. RVGSharedPri agent
      1.  
        Dependencies
      2.  
        Agent functions
      3.  
        State definitions
      4.  
        Attributes
      5.  
        Resource type definitions
      6.  
        Sample configurations
    8. VFRJob agent
      1.  
        Overview
      2. Dependencies for VFRJob agent
        1.  
          Group dependency for VFRJob agent in Custer File Systems or VxFS File Systems
        2.  
          Group dependency for VFRJob agent in VxFS File Systems
      3.  
        High availability of scheduler and replicator daemons
      4.  
        Agent functions for VFRJob agent
      5.  
        State definitions for VFRJob agent
      6.  
        Attributes for VFRJob Agent
      7.  
        Resource type definitions for VFRJob agent
      8.  
        High availability of VFR daemons
      9.  
        Configuration of VFRJob service groups on the source system
      10.  
        Sample configuration of VFRJob agent on source system
      11.  
        Configuration for VFRJob service groups on the target system
      12.  
        Sample configuration of VFRJob agent on target system
      13.  
        Changing file replication direction
      14. Notes for the VFRJob agent
        1.  
          Using a different port number for the replication daemon

AzureIP agent

The AzureIP agent manages the networking resources in an Azure environment. The following are the networking resources:

  • Private IP - Private IP is a private numerical address that networked devices use to communicate with one another. Private IP is used for communication within an Azure virtual network (VNet), and an on-premise network when you use a VPN gateway or ExpressRoute circuit to extend your network to Azure.

  • Public IP - Public IP address is a numerical address that is used for communication with the Internet, including Azure public-facing services.

  • Overlay IP - Overlay IP provides IP failover functionality for nodes spread across subnets. Overlay IP allows you to redirect IP address traffic to another cluster node belonging to different subnet within the same VNet. Overlay IP must be outside the VNet Classless Inter-Domain Routing (CIDR) block.

    Note:

    OverlayIP does not work across Regions if VNet-to-VNet tunneling is used.

The agent uses Azure Python APIs to associate IP resources in a Azure VM. The agent does the following:

  • Gets the NIC details, create the IP configuration and associate and disassociates private IP address

  • Associates and disassociates Public IP address with Private IP address

  • Manages route table entries of overlay IP for failing over across subnets