The high availability manager supports multihomed hosts, which
means that WebSphere Application Server processes can communicate with each
other even if they are running on different versions of the product. If you
are running Version 6.0.1.2 processes that need to communicate with each other,
there are high availability manager-related issues that you need to consider.
About this task
In Version 6.0.1 without Fix Pack 2 installed, an acceptable value
for the DCS_UNICAST_ADDRESS host name field is either a host name, for example,
myhost.mydomain, or a textual IP address, for example, 192.168.0.2. If a host
name is specified, Domain Name Services (DNS) is used to resolve the host
name to an IP address. If the host supports multiple IP addresses, where the
host name has multiple mappings in DNS, a host name is ambiguous and a textual
IP address is required.
After the installation of Version 6.0.1 Fix Pack
2, the asterisk is recognized as a valid value for the DCS_UNICAST_ADDRESS
host name field. When this field is set to an asterisk, multihome support
allows the high availability manager to open and receive connections on all
IP addresses available for the host.
With the introduction of Version
6.0.1 Fix Pack 2, processes can be classified into three separate categories:
- Type 1
- Processes that can operate only in single-IP mode. This category includes
processes on Version 6.0 nodes or Version 6.0.1 nodes that do not have Version
6.0.1 Fix Pack 2 installed.
- Type 2
- Processes on Version 6.0.1 nodes that have Version 6.0.1 Fix Pack 2 installed,
but do not have the DCS_UNICAST_ADDRESS host name field for the process set
to an asterisk.
- Type 3
- Processes on Version 6.0.1 nodes that have Version 6.0.1 Fix Pack 2 installed
and have the DCS_UNICAST_ADDRESS host name field for the process set to an
asterisk.
The following interoperability rules apply to these
process types:
To enable interoperating with Version 6.0.1.2 processes:
What to do next
After multihome support is enabled, all of the new nodes that are
added to the installation must have multihome support enabled. The base Version
6.0.1 code and Version 6.0.1 Fix Pack 2 must be installed before profiles
are created and the node is added. If this procedure is not observed, manual
configuration is required to enable the processes to connect.
Your configuration
cannot contain a mix of type 1 and type 3 processes. To ensure a valid configuration:
- Check for type 1 processes. Type 1 processes log the following message,
which indicates that the host name for another process in the core group is
an asterisk:
HMGR0024W: An error was encountered while looking up the IP address for
the host name of a core group member. The host name is * and the server
name is myCell01\myCellManager01\dmgr. The member will be excluded from
the core group.
- Check for type 3 processes. Type 3 processes do not display in a view
with type 1 processes, but can be detected by examining the HMGR0218 messages
the various processes log. If the processes connect, the same message is logged
across all processes. Specifically, processes that connect have the same view
identifier and the same number of processes in the view.
HMGR0218I: A new core group view has been installed. The core group is
defaultCoreGroup. The view identifier is (8:0.spoletoCell01\
spoletoCellManager01\dmgr). The number of members in the new view is 2.