Considerations for modifying properties of networks and network aliases

The following considerations apply to modifying properties of networks and network aliases:

You can modify only the configurable properties of a network or network alias. You cannot modify any property that has a value that’s generated or derived by HCP.

You cannot change the name of a network while that network is associated with a tenant or referenced by an alias. You cannot change the name of an alias while that alias is associated with a tenant.

You cannot change a network to an alias or an alias to a network.

When you take any of these actions for a network, communication on that network is temporarily disrupted:

oModify the VLAN ID or MTU. However, in the case of MTU, applications may not notice the disruption.

oModify the IPv4 gateway or netmask (if defined)

oModify the primary or secondary IPv6 gateway or IPv6 address prefix length (if defined)

oAdd or remove all settings for the secondary IPv6 configuration, including the gateway, prefix length, and node IP addresses

oDisable support for IPv4 addresses, which automatically removes all IPv4 configuration settings, including the gateway, subnet mask, and node IP addresses. (Removing all these settings automatically disables support for IPv4 addresses.)

oDisable support for IPv6 addresses, which automatically removes all IPv6 configuration settings, including the gateway, prefix length, and node IP addresses for the primary IPv6 subnet and, if defined, for the secondary IPv6 subnet. (Removing all these settings automatically disables support for IPv6 addresses.)

oAdd or remove the IP address assignments for one or more nodes.

The following considerations apply to modifying the IP Configuration settings for a network:

oThe [hcp_system] network IP mode determines the IP modes that are supported for user-defined networks:

You can configure a network to use a specific type of IP address (IPv4 or IPv6) only if the [hcp_system] network is also configured to use that type of IP address. However, If the [hcp_system] network is configured to use both IPv4 and IPv6 addresses, you can configure a network to use only IPv4 addresses, only IPv6 addresses, or both types of IP addresses.

If the [hcp_system] network is configured to use IPv6 addresses, you can configure a network to use a primary IPv6 subnet and, optionally, a secondary IPv6 subnet. The number of IPv6 subnets that are defined for the [hcp_system] network does not affect the number of IPv6 gateways that can be defined for a user-defined network.

oTo configure a network to use an IPv4 subnet, you need to define both the gateway and the subnet mask for that IPv4 subnet.

oYou can assign IPv4 addresses to nodes for a network only if an IPv4 subnet is defined for that network. All IPv4 addresses defined for a network must be on the IPv4 subnet defined for that network.

oTo configure a network to use an IPv6 subnet (whether it’s a primary or secondary IPv6 subnet), you need to define both the gateway and the prefix length for that subnet.

oA secondary IPv6 subnet can be defined for a network only if a primary IPv6 subnet is also defined for that network.

oWhen hidden master or notify is enabled for a network, if you configure that network to use a secondary IPv6 subnet, you also need to review and, if necessary, modify the list of downstream DNS server IP addresses configured for that network to ensure that each IPv6 address either is on the secondary IPv6 subnet or is routable from the primary IPv6 gateway that’s defined for the network.

oYou can assign primary IPv6 addresses to nodes for a network only if a primary IPv6 subnet is defined for that network. All primary IPv6 addresses defined for a network must be on the primary IPv6 subnet defined for that network.

oYou can assign secondary IPv6 addresses to nodes for a network only if a secondary IPv6 subnet is defined for that network. All secondary IPv6 addresses defined for a network must be on the secondary IPv6 subnet defined for that network.

oTo include a node in a network, you need to assign a separate IP address to that node on each IPv4 and IPv6 subnet that is defined for the network.

Note: To configure a partial network, you need to ensure that each node in the HCP system either has no IP addresses for the network or has an IP address on every IPv4 and IPv6 subnet that is defined for the network.

Selecting a different domain for a network has no effect on requests currently being serviced over that network. However, in subsequent requests, clients using that network need to specify the new domain name in the request URL.

If the HCP system is configured for DNS and you select a different domain for a network, make sure you change the domain name in the DNS to specify the name of the new domain for the network.

After you select a different domain for a network that’s being used for tenant management, any clients connected to the Tenant Management Console for the applicable tenants at the time of the change need to close all browser windows to clear cookies so they can access the Console using the new domain name.

If you select a different domain for the network that’s used for replication and the other system in the replication pair identifies the current system by its domain name, you need to modify the domain name in the definition of the replication link. Similarly, if you change the node IP addresses for the network that’s used for replication and the other system in the replication pair identifies the current system by its IP addresses, you need to modify the IP addresses in the definition of the replication link.

For the network that’s currently selected for replication, all nodes must have IP addresses. You can change but cannot remove IP addresses for that network.

You can disable or reenable a network at any time. If you disable the network that’s currently selected for replication, the status of all replication links in which the HCP system participates changes to broken, and replication or recovery, as applicable, stops on those links. If you then reenable the network, replication or recovery resumes automatically on those links.

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