TCP/IP profile updates
The following z/OS TCP/IP profile updates must be made before provisioning and starting a zCX
instance.
- DVIPAs for zCX must be defined using VIPARANGE statements with the ZCX attribute.
- Multiple DVIPAs can be defined on a single VIPARANGE statement if they belong to the same
subnet.
- The DVIPA specified in the provisioning workflows must have a matching VIPARANGE definition in
the TCP/IP profile when the zCX instance is started. Otherwise, zCX initialization will fail.
- Sysplex considerations: If you need the capability of restarting a zCX instance across other
systems in the sysplex, then include the same VIPARANGE statements on all systems in the sysplex on
which the zCX instance can be started.
IPv4/IPv6 dual-stack
Specifying an IPv6 address for the ZCX_GUESTIPV6 variable enables dual-stack
support. This allows use of IPv4 and IPv6 protocols with any container, service, or network. Docker
can communicate with both IPv4 and IPv6 endpoints. These endpoints can include DNS servers,
registries, proxies, and LDAP.
The following network information is used to provision a zCX instance:
Table 1. Unique network settings for each zCX
instance
| Variable |
Description |
| ZCX_GUESTIPv4 |
This is a unique guest IP address. It must be a zCX DVIPA IPv4 address. |
| ZCX_HOSTNAME |
This is a hostname for the zCX appliance instance. |
| ZCX_GUESTIPV6 |
This is a unique guest IPv6 address. This variable must be specified with the
ZCX_GUESTIPV4 variable. Specifying an IPv6 address enables IPv4/IPv6 dual-stack
support. |
Table 2. Additional
network settings that may be shared across multiple zCX instances
| Variable |
Description |
| ZCX_HOSTDNS1 and ZCX_HOSTDNS2 |
These are DNS Server IP Addresses. Up to two IP addresses can be specified for resiliency.
These IP addresses can be either IPv4 or IPv6 format. IPv6 format is only allowed if the variable
ZCX_GUESTIPV6 is assigned a value. These IP addresses may be the same as the DNS
Server IP addresses configured in the z/OS Resolver (NSINTERADDR or
NAMESERVER statements in TCPIP.DATA). |
| ZCX_HOSTDNS_SEARCH |
This is the DNS Search Domain. Specify the list of domain names that are appended, in the
order listed, to the host name to form the fully qualified domain name of a host being queried. This
is similar to z/OS Resolver configuration SEARCH statement in TCPIP.DATA. |
Table 3. Optional
network configuration options that may be shared across multiple zCX instances
| Variable |
Description |
| ZCX_MTU |
This is the MTU size to be used for IP communications. Check with your network administrator
to obtain this information. The default MTU size is 1492, which should be suitable for most
environments. A larger MTU can be specified to optimize local communications inside the same z/OS
system (to z/OS applications or to other zCX instances). When a larger MTU is specified, then all
network peers communicating with the zCX instance must have path MTU discovery enabled across the
network. |
| ZCX_TCPIPNAME |
This is the TCP/IP Stack name that is only needed if your z/OS system has multiple TCP/IP
stacks configured (CINET configuration). If multiple stacks are configured, this variable indicates
the TCP/IP stack to which the zCX instance should connect. If you omit the TCP/IP stack name in a
multi-stack configuration, zCX will attempt to connect to each TCP/IP stack that is active until a
successful connection is made (the specified DVIPA is successfully found and activated). |
| ZCX_MTU_IPV6 |
This is the MTU size for ZCX_GUESTIPV6. This variable is only valid if the variable
ZCX_GUESTIPV6 is set. It is to be used for IP communications. Check with your network administrator
to obtain this information. The default MTU size is 1492, which should be suitable for most
environments. You can specify a larger MTU to optimize local communications inside the same z/OS
system (to z/OS applications or to other zCX instances). When a larger MTU is specified, all network
peers communicating with the zCX instance must have path MTU discovery enabled across the
network. |