Interoperate with v6.0.1.2 processes

The high availability manager supports multihomed hosts, which means that the product processes can communicate with each other even if they are running on different versions of the product. If we are running v6.0.1.2 processes that need to communicate with each other, there are high availability manager-related issues needed to consider.

Know the version levels of the processes that need to communicate with each other. If no V6.0.1.2 processes exist, see Interoperating with v6.0.2 and later processes.

In v6.0.1 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 v6.0.1 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 v6.0.1 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 v6.0 nodes or v6.0.1 nodes that do not have v6.0.1 Fix Pack 2 installed.

Type 2

Processes on v6.0.1 nodes that have v6.0.1 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 v6.0.1 nodes that have v6.0.1 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:

• Type 1 and type 2 processes can interoperate.

• Type 2 and type 3 processes can also interoperate.

• Type 1 and type 3 processes cannot interoperate.

  Therefore, careful planning is necessary before converting processes to type 3 processes.

To enable interoperating with v6.0.1.2 processes:

Tasks

1. Add multihome capability by installing v6.0.1 Fix Pack 2. This step changes the existing type 1 processes to type 2 processes.
   1. Apply v6.0.1 Fix Pack 2 to all existing nodes. Nodes on which v6.0.1 Fix Pack 2 is installed continue to interoperate with nodes on which this fix pack is not installed, as long as the configuration does not change.

2. Stop all application servers.

3. Ensure that the deployment manager and all of the node agents are running.

4. Change the DCS_UNICAST_ADDRESS Host name field of each process to an asterisk. This step changes the existing type 2 processes to type 3 processes.

   1. In the administrative console, go to the configuration data for one of the processes on the new nodes:

      • For an application server, click...

                Servers > Server Types > WebSphere application servers > server. Then, in the Additional Properties section, click > Ports > port_name .

      • For a node agent, click...

                System Administration > Node agents > node. Then, in the Additional Properties section,, click > Ports > port_name .

      • For a deployment agent, click...

                System Administration > Deployment manager. Then, in the Additional Properties section, click > Ports > port_name .

   2. Click View associated transports for the port associated with the DCS transport channel to review.

   3. Click DCS_UNICAST_ADDRESS, and enter the name of the new host in the Host field.

   4. Click OK> Save.

   5. Repeat the previous steps until the new host name is added for all of the processes on the new nodes.

   6. Select Synchronize changes with nodes, and then click Save again.

5. Stop all of the servers that contain the processes with configuration changes.

6. Restart these servers.

All of the processes can communicate with each other.

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 v6.0.1 code and v6.0.1 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:

1. 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.
   

2. 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.