Requirements for IBM z/OS Container Platform IP addresses

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z/OS® Communications Server provides network communications and network-related services for IBM® z/OS Container Platform (zOSCP). The IP addresses for zOSCP are represented as a new type of VIPARANGE dynamic VIPA (DVIPA) called a ZCONTAINER DVIPA.

You need to define the range of dynamic VIPAs to be used when starting a container by using Podman for IBM z/OS (Podman). This dynamic VIPA range cannot overlap with other IP addresses that you have defined on your TCP/IP profile.

To create this range of dynamic VIPAs, you might use the following VIPARANGE statement:

VIPARANGE DEFINE 255.255.255.248 192.0.2.248 ZCONTAINER

This definition defines 8 IP addresses (192.0.2.248, 192.0.2.249, 192.0.2.250, 192.0.2.251, 192.0.2.252, 192.0.2.253, 192.0.2.254, 192.0.2.255). Although 8 IP addresses are defined, only IP addresses 192.0.2.249 - 192.0.2.254 are available to be used. The first and last IP addresses in the range are reserved for the subnet's network and broadcast IP addresses.

You need to configure a SRCIP DESTINATION statement for the VIPARANGE ZCONTAINER subnet to ensure that a valid source IP address is used when local z/OS client applications connect to server applications running in a zOSCP environment. The source IP specified on the statement must already be defined on the TCP/IP instance and cannot be part of the VIPARANGE ZCONTAINER subnet.

For example, if VIPARANGE 255.255.255.248 192.0.2.248 ZCONTAINER is defined and 192.0.2.50 is an existing static VIPA, the following would allow connections from the local system to a container:

SRCIP 
DESTINATION 192.0.2.248/29 192.0.2.50 
ENDSRCIP

For more information, see Network Support for IBM z/OS Container Platform which covers the Communications Server enhancements in support of zOSCP.