Change Cluster Node Entry (CHGCLUNODE)

The Change Cluster Node Entry (CHGCLUNODE) command is used to change cluster membership information for a cluster node entry. The information that can be changed is the cluster interface addresses defined for the node and status of the node. The node entry which is being changed may or may not have Cluster Resource Services started.

You can add, remove, or replace an interface address for the cluster node. The cluster interface address is an IP address that is used by Cluster Resource Services to communicate with other nodes in the cluster. The IP address may be an IPv4 address (for any cluster version) or IPv6 address (if current cluster version is 7 or greater).

An IPv4 internet address is specified in the form nnn.nnn.nnn.nnn, where nnn is a decimal number ranging from 0 through 255. An IPv4 internet address is not valid if it has a value of all binary ones or all binary zeros for the network identifier (ID) portion or the host portion of the address.

An IPv6 internet address must be a unicast address and must not contain an imbedded IPv4 address (compatibility or mapped). An IPv6 internet address is specified in the form x:x:x:x:x:x:x:x, where x is a hexadecimal number ranging from 0 through X'FFFF'. The "::" may be used once in the IPv6 address to indicate one or more groups of 16 bits of zeros. The "::" may be used to compress leading, imbedded, or trailing zeros in the address.

If the IP address is entered from the command line, the address must be enclosed in apostrophes.

You can also change the the status of a node to Failed. Using this command to change the status of a node to Failed provides a way to tell Cluster Resource Services that a node has really failed. There are certain failure conditions that Cluster Resource Services cannot detect as a node failure. Rather, the problem appears to be a communication problem and the cluster looks like it has become partitioned. By telling Cluster Resource Services that a node has failed, it makes recovery from the partition state simpler for primary-backup model cluster resource groups since a backup node from the remaining active cluster nodes can then be assigned as the primary node.

For primary-backup model cluster resource groups:

When you change the status of a node to Failed, the role of nodes in the recovery domain for each cluster resource group in the partition may be reordered by assigning the specified node as the last backup. If an exit program is specified for the cluster resource group, it will be called with an action code of Change Node Status. If multiple nodes have failed and their status needs to be changed, the order in which the nodes are changed will affect the final order of the recovery domain's backup nodes in the cluster resource group.
If the node status is changed to failed and the node was the primary node for a cluster resource group, the first active backup will be reassigned as the new primary node. When this occurs for a device cluster resource group, ownership of the hardware will be moved to the new primary node.

If a problem is detected and the command does not complete successfully, the command can be run again once the problem is corrected. Any cluster resource group that had already had the status of a node changed from Partition to Failed and the recovery domain order changed will not be affected by running this command again.

Warning: Changing the node status to failed when, in fact, the node is still active and a true partition has occurred should not be done. Doing so for primary-backup model cluster resource groups, allows a node in each partition to become the primary node for a cluster resource group. When two nodes think they are the primary node, data such as files or data bases could become corrupted if two different nodes are each making independent changes to copies of their files. In addition, the two partitions cannot be merged back together when a node in each partition has been assigned the primary role.

Restrictions:

You must have input/output system configuration (*IOSYSCFG) special authority on all nodes in the cluster to run this command.
This command cannot be called from a cluster resource group exit program.
This command must be called from a program running on a cluster node with a status of Active.
If the cluster is in a partitioned state, this operation can only be performed within the partition running the command.
Only one cluster interface address can be changed at a time. If the cluster is in partitioned state, the change cluster interface address is only allowed for a node within the same partition.
To change the cluster node status, only a node that has a status of Partition or Failed can be changed and it can only be changed to Failed status.

Keyword	Description	Choices	Notes
CLUSTER	Cluster	Name	Required, Positional 1
NODE	Node identifier	Name	Required, Positional 2
OPTION	Option	ADDIFC, RMVIFC, CHGIFC, CHGSTS	Required, Positional 3
OLDINTNETA	Old IP address	Character value	Optional, Positional 4
NEWINTNETA	New IP address	Character value	Optional, Positional 5

Old IP address (OLDINTNETA)

Specifies the cluster interface address which is being replaced or removed. The interface address may be an IPv4 address (for any cluster version) or IPv6 address (if current cluster version is 7 or greater).

If the IP address is entered from the command line, the address must be enclosed in apostrophes.

This is a required parameter.

character-value: Specify the cluster interface address to be changed.

New IP address (NEWINTNETA)

Specifies the cluster interface address which is being added to the node information or replacing an old cluster interface address. The interface address may be an IPv4 address (for any cluster version) or IPv6 address (if current cluster version is 7 or greater).

If the IP address is entered from the command line, the address must be enclosed in apostrophes.

This is a required parameter.

character-value: Specify the cluster interface address which is to be used to communicate with the node.