Subcloud Deployment Phases

Subclouds can be deployed using individual phases.

When a subcloud is deployed using a single operation dcmanager subcloud add that comprises different deployment phases and if there is a failure on any of the phases, you would need to wait for the entire operation to timeout.

Thus, instead of using a single operation, a subcloud can be deployed by executing each phase individually. This gives a user more control of the deployment process, allowing the execution of individual phases one at a time, with the possibility of aborting and resuming the deployment.

About this task

After physically installing the hardware and network connectivity of a subcloud, the subcloud deployment process executes the following phases in the central cloud:

  • The dcmanager subcloud deploy create command.

    Sets up the subcloud configuration in the central cloud.

  • The dcmanager subcloud deploy install command.

    Uses Redfish Virtual Media Service to remotely install the ISO on controller-0 in the subcloud.

  • The dcmanager subcloud deploy bootstrap command.

    Uses Ansible to bootstrap StarlingX on controller-0 in the subcloud.

  • The dcmanager subcloud deploy config command.

    Uses Ansible to run deploy config on controller-0 in the subcloud.

  • The dcmanager subcloud deploy complete command.

    If the subcloud is manually configured post bootstrap, it concludes the subcloud deployment.

Note

Remove all the removable USB storage devices from the subcloud servers before installing a Redfish remote subcloud.

Prerequisites

  • A new system CLI option --active is added to the load-import command to allow the import into the system controller /opt/dc-vault/loads. The purpose of this is to allow Redfish install of subclouds referencing a single full copy of the bootimage.iso at /opt/dc-vault/loads. (Previously, the full bootimage.iso was duplicated for each subcloud add command).

    Note

    This is required only once and does not have to be done for every subcloud install.

    The dcmanager command recognizes bootimage names that end with .iso and .sig. For example:

    ~(keystone_admin)]$ system --os-region-name SystemController load-import --active |installer-image-name|.iso |installer-image-name|.sig
    

    The ISO imported via load-import --active must be at the same patch level as the system controller. This ensures that the subcloud boot image aligns with the patch level of the load to be installed on the subcloud.

    Warning

    If the patch level of load-imported ISO does not match the system controller patch level, the subcloud patch state may not align with the system controller patch state.

  • Run the load-import command on controller-0 to import the new release. You can specify either the full file path or relative paths to the *.iso bootimage file and to the *.sig bootimage signature file.

    $ source /etc/platform/openrc
    ~(keystone_admin)]$ system load-import [--local] /home/sysadmin/<bootimage>.iso <bootimage>.sig
    
    +--------------------+-----------+
    | Property           | Value     |
    +--------------------+-----------+
    | id                 | 2         |
    | state              | importing |
    | software_version   | nn.nn     |
    | compatible_version | nn.nn     |
    | required_patches   |           |
    +--------------------+-----------+
    

The load-import must be done on controller-0.

(Optional) If --local is specified, the ISO and sig files are uploaded directly from the active controller, where <local_iso_file_path> and <local_sig_file_path> are paths on the active controller to load ISO files and sig files, respectively.

Note

  • If --local is specified, the ISO and sig files are transferred directly from the active controller filesystem to the load directory, otherwise the files are transferred via the API.

  • This may take a few minutes to complete.

In order to deploy subclouds from either controller, all local files that are referenced in the subcloud-bootstrap-values.yaml file must exist on both controllers (for example, /home/sysadmin/docker-registry-ca-cert.pem).

Procedure

  1. At the subcloud location, physically install the servers and network connectivity required for the subcloud.

    Note

    Do not power off the servers. The host portion of the server can be powered off, but the BMC portion of the server must be powered and accessible from the system controller.

    There is no need to wipe the disks.

    Note

    The servers require connectivity to a gateway router that provides IP routing between the subcloud management or admin subnet and the system controller management subnet, and between the subcloud OAM subnet and the system controller subnet.

  2. Create the subcloud-install-values.yaml file and use the content to pass the file into the dcmanager subcloud deploy create command, using the --install-values command option.

    Note

    If the subcloud will be manually installed, skip this step and go to deploy bootstrap.

    Note

    If your controller is on a ZTSystems Triton server that requires a longer timeout value, you can now use the rd.net.timeout.ipv6dad dracut parameter to specify an increased timeout value for dracut to wait for the interface to have carrier, and complete IPv6 duplicate address detection DAD. For the ZTSystems server, this can take more than four minutes. It is recommended that you set this value to 300 seconds, by specifying the following in the subcloud-install-values.yaml file:

    rd.net.timeout.ipv6dad: 300
    

    Note

    The wait_for_timeout value must be chosen based on your network performance (bandwidth, latency, and quality) and should be increased if the network does not meet the minimum or timeout requirements. The default value of 3600 seconds is based on a network bandwidth of 100 Mbps with a 50 ms delay.

    For example, --install-values /home/sysadmin/subcloud-install-values.yaml.

    bootstrap_interface: <bootstrap_interface_name> # e.g. eno1
    bootstrap_address: <bootstrap_interface_ip_address> # e.g.128.224.151.183
    bootstrap_address_prefix: <bootstrap_netmask> # e.g. 23
    
    # Board Management Controller
    bmc_address: <BMCs_IPv4_or_IPv6_address> # e.g. 128.224.64.180
    bmc_username: <bmc_username> # e.g. root
    
    # If the subcloud's bootstrap IP interface and the system controller are not on the
    # same network, then the customer must configure a default route or static route
    # so that the Central Cloud can login bootstrap the newly installed subcloud.
    
    # If nexthop_gateway is specified and the network_address is not specified then a
    # default route will be configured. Otherwise, if a network_address is specified then
    # a static route will be configured.
    
    nexthop_gateway: <default_route_address> for  # e.g. 128.224.150.1 (required)
    network_address: <static_route_address>   # e.g. 128.224.144.0
    network_mask: <static_route_mask>         # e.g. 255.255.254.0
    
    # Installation type codes
    #0 - Standard Controller, Serial Console
    #1 - Standard Controller, Graphical Console
    #2 - AIO, Serial Console
    #3 - AIO, Graphical Console
    #4 - AIO Low-latency, Serial Console
    #5 - AIO Low-latency, Graphical Console
    install_type: 3
    
    # Optional parameters defaults can be modified by uncommenting the option with a modified value.
    
    # This option can be set to extend the installing stage timeout value
    # wait_for_timeout: 3600
    
    # Set this options for https
    no_check_certificate: True
    
    # If the bootstrap interface is a vlan interface then configure the vlan ID.
    # bootstrap_vlan: <vlan_id>
    
    # Override default filesystem device.
    # rootfs_device: "/dev/disk/by-path/pci-0000:00:1f.2-ata-1.0"
    # boot_device: "/dev/disk/by-path/pci-0000:00:1f.2-ata-1.0"
    
    # Set the value for persistent file system (/opt/platform-backup).
    # The value must be whole number (in MB) that is greater than or equal
    # to 30000.
    persistent_size: 30000
    
    # Configure custom arguments applied at boot within the installed subcloud.
    # Multiple boot arguments can be provided by separating each argument by a
    # single comma. Spaces are not allowed.
    # Example: extra_boot_params: multi-drivers-switch=cvl-2.54
    # extra_boot_params:
    

    Note

    By default, 30GB is allocated for /opt/platform-backup. If additional persistent disk space is required, the partition can be increased in the next subcloud redeploy using the following commands:

    • To increase /opt/platform-backup to 40GB, add the persistent_size: 40000 parameter to the subcloud-install-values.yaml file.

    • Use the dcmanager subcloud update command to save the configuration change for the next subcloud redeployment.

      ~(keystone_admin)]$ dcmanager subcloud update --install-values <subcloud-install-values.yaml> <subcloud-name>
      

    For a new subcloud deployment, use the dcmanager subcloud deploy create command with the subcloud-install-values.yaml file containing the desired persistent_size value.

  3. At the system controller, create a /home/sysadmin/subcloud-bootstrap-values.yaml overrides file for the subcloud.

    For example:

    system_mode: simplex
    name: "subcloud"
    
    description: "test"
    location: "loc"
    
    management_subnet: 192.168.101.0/24
    management_start_address: 192.168.101.2
    management_end_address: 192.168.101.50
    management_gateway_address: 192.168.101.1
    
    external_oam_subnet: 10.10.10.0/24
    external_oam_gateway_address: 10.10.10.1
    external_oam_floating_address: 10.10.10.12
    
    systemcontroller_gateway_address: 192.168.204.101
    
    docker_registries:
      k8s.gcr.io:
        url: registry.central:9001/k8s.gcr.io
      gcr.io:
        url: registry.central:9001/gcr.io
      ghcr.io:
        url: registry.central:9001/ghcr.io
      quay.io:
        url: registry.central:9001/quay.io
      docker.io:
        url: registry.central:9001/docker.io
      docker.elastic.co:
        url: registry.central:9001/docker.elastic.co
      registry.k8s.io:
        url: registry.central:9001/registry.k8s.io
      icr.io:
        url: registry.central:9001/icr.io
      defaults:
        username: sysinv
        password: <sysinv_password>
        type: docker
    

    Where <sysinv_password> can be found by running the following command as ‘sysadmin’ on the central cloud:

    $ keyring get sysinv services
    

    In the above example, if the admin network is used for communication between the subcloud and system controller, then the management_gateway_address parameter should be replaced with admin subnet information.

    For example:

    management_subnet: 192.168.101.0/24
    management_start_address: 192.168.101.2
    management_end_address: 192.168.101.50
    admin_subnet: 192.168.102.0/24
    admin_start_address: 192.168.102.2
    admin_end_address: 192.168.102.50
    admin_gateway_address: 192.168.102.1
    

    This configuration will install container images from the local registry on your central cloud. The central cloud’s local registry’s HTTPS Certificate must have the central cloud’s OAM IP, registry.local and registry.central in the certificate’s SAN list. For example, a valid certificate contains a SAN list:

    "DNS.1: registry.local DNS.2: registry.central IP.1: floating_management IP.2: floating_OAM"
    

    If required, run the following command on the central cloud prior to bootstrapping the subcloud to install the new certificate for the central cloud with the updated SAN list:

    ~(keystone_admin)]$ system certificate-install -m docker_registry path_to_cert
    

    If you prefer to install container images from the default external registries, make the following substitutions for the docker_registries sections of the file.

    docker_registries:
      defaults:
       username: <your_default_registry_username>
       password: <your_default_registry_password>
    
  4. Create the subcloud using dcmanager.

    When calling the subcloud deploy create command, specify the install values, bootstrap values, deploy config values, and the subcloud’s sysadmin password.

    ~(keystone_admin)]$ dcmanager subcloud deploy create \
    --bootstrap-address <oam_ip_address_of_subclouds_controller-0> \
    --bootstrap-values /home/sysadmin/subcloud1-bootstrap-values.yaml \
    --deploy-config /home/sysadmin/subcloud1-deploy-config.yaml \
    --install-values /home/sysadmin/install-values.yaml \
    --bmc-password <bmc_password>
    --release <software-release>
    

    If --sysadmin-password is not specified, you are prompted to enter it once the full command is invoked. The password is masked when it is entered.

    Enter the sysadmin password for the subcloud:
    

    (Optional) The --deploy-config option must reference the deployment configuration file mentioned above. In the deployment configurations, static routes from the management or admin interface of a subcloud to the system controller’s management subnet must be explicitly listed. This ensures that the subcloud comes online after deployment. If the admin network is used for communication between the system controller and subcloud, the deployment configuration file must include both an admin network type and a management network type interface.

    (Optional) The --bmc-password <password> option is used for subcloud installation and is required only if the --install-values option is specified.

    If the --bmc-password <password> option is omitted and the --install-values option is specified, the system administrator will be prompted to enter it, following the dcmanager subcloud deploy create command. This option is ignored if the --install-values option is not specified. The password is masked when it is entered.

    Enter the bmc password for the subcloud:
    

    The dcmanager subcloud show or dcmanager subcloud list command can be used to view subcloud deploy create status.

    The deploy status field has the following values for this phase:

    Creating

    This status indicates that the subcloud configuration is being created based on provided files and parameters.

    Create-failed

    This status indicates that the subcloud creation stage failed. Check /var/log/dcmanager/dcmanager.log for more details on the failure.

    Create-complete

    This status indicates that the subcloud was successfully created.

  5. Install the subcloud using dcmanager.

    To install the subcloud using Redfish Virtual Media Service, use the subcloud deploy install command. Both --install-values and --release parameters are optional if they were provided previously, and will replace them if present on request.

    ~(keystone_admin)]$ dcmanager subcloud deploy install <subcloud-name> \
    --install-values /home/sysadmin/install-values.yaml \
    --sysadmin-password <sysadmin_password> \
    --bmc-password <bmc_password> \
    --release <software-release>
    

    If --sysadmin-password is not specified, you are prompted to enter it once the full command is invoked. The password is masked when it is entered.

    Enter the sysadmin password for the subcloud:
    

    (Optional) The --bmc-password <password> option is used for subcloud installation and is required only if the --install- values option is specified.

    If the --bmc-password <password> option is omitted and the --install-values option is specified, the system administrator will be prompted to enter it, following the dcmanager subcloud add command. This option is ignored if the --install-values option is not specified. The password is masked when it is entered.

    Enter the bmc password for the subcloud:
    

    The dcmanager subcloud show or dcmanager subcloud list command can be used to view subcloud deploy install progress.

    The deploy status field has the following values for this phase:

    Pre-Install

    This status indicates that the ISO for the subcloud is being updated by the central cloud with the boot menu parameters and kickstart configuration as specified in the install-values.yaml file.

    Pre-Install-failed

    This status indicates that the ISO preparation stage failed. Check /var/log/dcmanager/dcmanager.log for more details on the failure.

    Installing

    This status indicates that the subcloud’s ISO is being installed from the central cloud to the subcloud using the Redfish Virtual Media service on the subcloud’s BMC.

    Install-failed

    This status indicates that the subcloud’s ISO installation failed. Check /var/log/dcmanager/ansible/<subcloud_name>_playbook_output.log or dcmanager subcloud errors for more details on the failure.

    Install-complete

    This status indicates that the subcloud’s ISO installation completed successfully.

  6. Bootstrap the subcloud using dcmanager.

    To bootstrap the subcloud, use the subcloud deploy bootstrap command. Both --bootstrap-address and --bootstrap-values parameters are optional, and will replace the previous values if provided.

    ~(keystone_admin)]$ dcmanager subcloud deploy bootstrap <subcloud-name> \
    --bootstrap-address <oam_ip_address_of_subclouds_controller-0> \
    --bootstrap-values /home/sysadmin/subcloud1-bootstrap-values.yaml \
    --sysadmin-password <sysadmin_password>
    

    If --sysadmin-password is not specified, you are prompted to enter it once the full command is invoked. The password is masked when it is entered.

    Enter the sysadmin password for the subcloud:
    

    The dcmanager subcloud show or dcmanager subcloud list command can be used to view subcloud deploy bootstrap progress.

    The deploy status field has the following values for this phase:

    Pre-bootstrap

    This status indicates that the necessary configurations for subcloud Ansible bootstrap are being generated based on the provided bootstrap-values.yaml file.

    Pre-bootstrap-failed

    This status indicates that the Ansible bootstrap preparation stage failed. Check /var/log/dcmanager/dcmanager.log for more details on the failure.

    Bootstrapping

    This status indicates that the Ansible bootstrap of StarlingX software on the subcloud’s controller-0 is in progress.

    Bootstrap-failed

    This status indicates that the subcloud Ansible bootstrap stage failed. Check /var/log/dcmanager/ansible/<subcloud_name>_playbook_output.log or dcmanager subcloud errors for more details on the failure.

    Bootstrap-complete

    This status indicates that the subcloud Ansible bootstrap operation completed successfully.

  7. Configure the subcloud using dcmanager.

    To configure the subcloud, use the subcloud deploy config command. The --deploy-config parameter is optional if it was provided previously, and will replace it if present on request.

    ~(keystone_admin)]$ dcmanager subcloud deploy config <subcloud-name> \
    --deploy-config /home/sysadmin/subcloud1-deploy-config.yaml \
    --sysadmin-password <sysadmin_password>
    

    If --sysadmin-password is not specified, you are prompted to enter it once the full command is invoked. The password is masked when it is entered.

    Enter the sysadmin password for the subcloud:
    

    (Optional) The --deploy-config option must reference the deployment configuration file mentioned above. In the deployment configurations, static routes from the management or admin interface of a subcloud to the system controller’s management subnet must be explicitly listed. This ensures that the subcloud comes online after deployment. If the admin network is used for communication between the system controller and subcloud, the deployment configuration file must include both an admin network type and a management network type interface.

    The dcmanager subcloud show or dcmanager subcloud list command can be used to view the subcloud deploy configuration status.

    The deploy status field has the following values for this phase:

    Pre-config

    This status indicates that the necessary configurations for deploy config are being generated based on the provided deploy-values.yaml file.

    Pre-config-failed

    This status indicates that the deploy config preparation stage failed. Check /var/log/dcmanager/dcmanager.log for more details on the failure.

    Configuring

    This status indicates that the deploy config playbook execution on the subcloud’s controller-0 is in progress.

    Config-failed

    This status indicates that the deploy config playbook failed. Check /var/log/dcmanager/ansible/<subcloud_name>_playbook_output.log or dcmanager subcloud errors for more details on the failure.

    Complete

    This status indicates that subcloud deployment is complete.

  8. Complete the subcloud deployment using dcmanager.

    When manually configuring the subcloud, the deployment must be concluded by running the subcloud deploy complete command.

    ~(keystone_admin)]$ dcmanager subcloud deploy complete <subcloud-name>
    

    The deploy status field will transition to Complete.

  9. At the Central Cloud / System Controller, monitor the progress of the subcloud install, bootstrapping, and deployment by using the deploy status field of the dcmanager subcloud list command.

    Caution

    If there is a failure during installation or bootstraping, you can resume the deployment using the dcmanager subcloud deploy resume command, or you can run individual phases with dcmanager subcloud deploy install, dcmanager subcloud deploy bootstrap or dcmanager subcloud deploy config.

  10. If deploy_status shows an installation, bootstrap, or deployment failure state, you can use the dcmanager subcloud errors command in order to get more detailed information about the failure.

    For example:

    [sysadmin@controller-0 ~(keystone_admin)]$ dcmanager subcloud errors 1
    FAILED bootstrapping playbook of (subcloud).
     detail: fatal: [subcloud]: FAILED! => changed=true
      failed_when_result: true
      msg: non-zero return code
        500 Server Error: Internal Server Error ("manifest unknown: manifest unknown")
         Image download failed: admin-2.cumulus.mss.com: 30093/wind-river/cloud-platform-deployment-manager: WRCP_22.06 500 Server Error: Internal Server Error ("Get https://admin-2.cumulus .mss.com: 30093/v2/: dial tcp: lookup admin-2.cumulus.mss.com on 10.41.0.1:53: read udp 10.41.1.3:40251->10.41.0.1:53: i/o timeout")
         Image download failed: gcd.io/kubebuilder/kube-rdac-proxy:v0.11.0 500 Server Error: Internal Server Error ("Get https://gcd.io/v2/: dial tcp: lookup gcd.io on 10.41.0.1:53: read udp 10.41.1.3:52485->10.41.0.1:53: i/o timeout")
        raise Exception("Failed to download images %s" % failed_downloads)
         Exception: Failed to download images ["admin-2.cumulus.mss.com: 30093/wind-river/cloud-platform-deployment-manager: WRCP_22.06", "gcd.io kubebuilder/kube-rdac-proxy:v0.11.0"]
    FAILED TASK: TASK [common/push-docker-images Download images and push to local registry] Wednesday 12 October 2022 12:27:31 +0000 (0:00:00.042)
    0:16:34.495
    
  11. You can also monitor detailed logging of the subcloud installation, bootstrapping, and deployment by monitoring the log file /var/log/dcmanager/ansible/<subcloud_name>_playbook_output.log on the active controller in the central cloud.

    For example:

    controller-0:/home/sysadmin# tail /var/log/dcmanager/ansible/subcloud_playbook_output.log
    k8s.gcr.io: {password: secret, url: null}
    quay.io: {password: secret, url: null}
    )
    
    TASK [bootstrap/bringup-essential-services : Mark the bootstrap as completed] ***
    changed: [subcloud]
    
    PLAY RECAP *********************************************************************
    subcloud                  : ok=230  changed=137  unreachable=0    failed=0
    

    Note

    The subcloud_playbook_output.log can rotate, the previous log file will be subcloud_playbook_output.log.1.

    If the install, bootstrap, or config phase fails, it can be re-executed using the same command that is used to trigger the deploy phase.

    If more debugging is required, set rvmc_debug_level in the install-values.yaml file. For more information, see Install a Subcloud Using Redfish Platform Management Service.

Abort and Resume the Subcloud Deployment

The subcloud deployment can be aborted and resumed for the install, bootstrap and config phases.

To abort the deployment, use the subcloud deploy abort command.

~(keystone_admin)]$ dcmanager subcloud deploy abort <subcloud-name>

View the subcloud deploy abort status by running the dcmanager subcloud show or dcmanager subcloud list command.

The deploy status field has the following values for this phase:

Aborting-<phase>

This status indicates that the current subcloud deployment phase is currently being aborted.

<phase>-aborted

This status indicates that the specified subcloud deployment phase is successfully aborted.

Note

If the dcmanager subcloud deploy abort <subcloud-name> command is called during the installation phase, the subcloud will be shut down via Redfish Virtual Media Service.

To resume the deployment, use the subcloud deploy resume command.

The parameter values will be reused from the previous phases if new ones are not provided in the request.

~(keystone_admin)]$ dcmanager subcloud deploy resume <subcloud-name> \
--bootstrap-address <oam_ip_address_of_subclouds_controller-0> \
--bootstrap-values /home/sysadmin/subcloud1-bootstrap-values.yaml \
--sysadmin-password <sysadmin_password> \
--deploy-config /home/sysadmin/subcloud1-deploy-config.yaml \
--install-values /home/sysadmin/install-values.yaml \
--bmc-password <bmc_password> \
--release <software-release>

Postrequisites

  • For detailed StarlingX procedures on manually configuring the subcloud for the desired deployment configuration, see the post-bootstrap steps of StarlingX Installation.

  • Check and update docker registry credentials on the subcloud:

    REGISTRY="docker-registry"
    SECRET_UUID='system service-parameter-list | fgrep
    $REGISTRY | fgrep auth-secret | awk '{print $10}''
    SECRET_REF='openstack secret list | fgrep $
    {SECRET_UUID} | awk '{print $2}''
    openstack secret get ${SECRET_REF} --payload -f value
    

    The secret payload should be username: sysinv password:<password>. If the secret payload is username: admin password:<password>, see Update Credentials Used by Subcloud for Install Registry (registry.central) for more information.

  • For more information on bootstrapping and deploying, see the procedures listed under Installation.

  • Add static route for nodes in subclouds to access openldap service.

    In DC system, openldap service is running on central cloud. In order for the nodes in the subclouds to access openldap service, such as ssh to the nodes as openldap users, a static route to the System Controller is required to be added in these nodes. This applies to controller nodes, worker nodes, and storage nodes (nodes that have sssd running).

    The static route can be added on each of the nodes in the subcloud using the system CLI.

    The following examples show how to add the static route in controller node and worker node:

    system host-route-add controller-0 mgmt0 <Central Cloud mgmt subnet> 64 <Gateway IP address>
    system host-route-add compute-0 mgmt0 <Central Cloud mgmt subnet> 64 <Gateway IP address>
    

    The static route can also be added using deploy config by adding the route in its configuration file.

    The following examples show how to add the route configuration in a controller and worker host profiles of the deploy config’s configuration file:

    Controller node:
    ---
    apiVersion: starlingx.windriver.com/v1
    kind: HostProfile
    metadata:
      labels:
        controller-tools.k8s.io: "1.0"
      name: controller-0-profile
      namespace: deployment
    spec:
      administrativeState: unlocked
      bootDevice: /dev/disk/by-path/pci-0000:c3:00.0-nvme-1
      console: ttyS0,115200n8
      installOutput: text
      ......
      routes:
          - gateway: <Gateway IP address>
        activeinterface: mgmt0
        metric: 1
        prefix: 64
        subnet: <Central Cloud mgmt subnet>
    
    Worker node:
    ---
    apiVersion: starlingx.windriver.com/v1
    kind: HostProfile
    metadata:
      labels:
        controller-tools.k8s.io: "1.0"
      name: compute-0-profile
      namespace: deployment
    spec:
      administrativeState: unlocked
      boardManagement:
        credentials:
          password:
            secret: bmc-secret
        type: dynamic
      bootDevice: /dev/disk/by-path/pci-0000:00:1f.2-ata-1.0
      clockSynchronization: ntp
      console: ttyS0,115200n8
      installOutput: text
      ......
      routes:
          - gateway: <Gateway IP address>
        interface: mgmt0
        metric: 1
        prefix: 64
        subnet: <Central Cloud mgmt subnet>