Commands Reference, Volume 3

mkcomg Command

Purpose

Creates a new communication group definition for a peer domain.

Syntax

mkcomg [-s sensitivity] [-p period] [-t priority] [-x {br}] [-e NIM_path] [-m NIM_parameters] [-i n:network_interface1[:node1] [,network_interface2[:node2]...] | -S n:"network_interface_selection_string"] [-h] [-TV] communication_group

Description

The mkcomg command creates a new communication group definition for an online peer domain with the name specified by the communication_group parameter. The communication group is used to define heartbeat rings for use by topology services and to define the tunables for each heartbeat ring. The communication group determines which devices are used for heartbeating in the peer domain.

The mkcomg command must be run on a node that is currently online in the peer domain where the communication group is to be defined. There can be more than one communication group in a peer domain.

The -e and -m flags are used to set the network interface module (NIM) path and parameters. The NIM path is the path to the NIM that supports the adapter types used in the communication group. The NIM parameters are passed to NIM when it is started. If -m is not specified, the parameters predefined by topology services are used.

The communication group can be assigned to one or more interface resources. Use the -i flag to assign the communication group to a specific interface resource name. The interface resource can be limited to one on a particular node. An interface resource can also be specified using the -S flag and a selection string. This is used when specifying the interface resource name is not sufficient. The -i and -S flags cannot be used together. The chcomg command can also be used to assign a communication group to an interface resource.

Flags

-s sensitivity

Specifies the heartbeat sensitivity. This is the number of missed heartbeats that constitute a failure. The sensitivity value is an integer greater than or equal to 2. The default value is 4.

-p period

Specifies the number of seconds between heartbeats. The period is an integer greater than or equal to 1. The default value is 1.

-t priority

Specifies the priority. This value indicates the importance of this communication group with respect to others. It is used to order the heartbeat rings. The lower the number means the higher the priority. The highest priority is 1. The default value is 1 for IP networks and 255 for RS232 networks.

-x br

Excludes controls for heartbeat mechanisms. This flag indicates that one or more controls for heartbeat mechanisms should not be used even if the underlying media support it. The following features can be excluded:

b: Specifies that the broadcast feature should not be used even if the underlying media support it. If -x b is not specified, the broadcast feature will be used if the underlying media support it.
r: Specifies that the source routing feature should not be used even if the underlying media support it. If -x r is not specified, the source routing feature will be used if the underlying media support it.

To exclude more than one control, specify the feature characters consecutively: -x br.

-e NIM_path

Specifies the network interface module (NIM) path name. This character string specifies the path name to the NIM that supports the adapter types in the communication group.

-m NIM_parameters

Specifies the NIM start parameters. This character string is passed to the NIM when starting it.

-i n:network_interface1[:node1] [,network_interface2[:node2]...

Assigns this communication group to the network interface resource defined by the network interface resource name and optionally the node name where it can be found.

If -i is specified, -S cannot be specified.

-S n:"network_interface_selection_string"

Assigns this communication group to the interface specified by the network interface selection string.

If -S is specified, -i cannot be specified.

-h

Writes the command's usage statement to standard output.

-T

Writes the command's trace messages to standard error. For your software service organization's use only.

-V

Writes the command's verbose messages to standard output.

Parameters

communication_group: Specifies the name of the new communication group that is to be created for the online peer domain. The name can contain any printable character.

Security

The user of the mkcomg command needs write permission for the IBM.CommunicationGroup resource class. Write permission for the IBM.NetworkInterface resource class is required to set the communication group for a network interface resource. By default, root on any node in the peer domain has read and write access to these resource classes through the configuration resource manager.

Exit Status

0: The command ran successfully.
1: An error occurred with RMC.
2: An error occurred with a command-line interface script.
3: An incorrect flag was entered on the command line.
4: An incorrect parameter was entered on the command line.
5: An error occurred that was based on incorrect command-line input.

Environment Variables

CT_CONTACT: Determines the system where the session with the resource monitoring and control (RMC) daemon occurs. When CT_CONTACT is set to a host name or IP address, the command contacts the RMC daemon on the specified host. If CT_CONTACT is not set, the command contacts the RMC daemon on the local system where the command is being run. The target of the RMC daemon session and the management scope determine the resource classes or resources that are processed.

Restrictions

This command must be run on a node that is defined and online to the peer domain where the communication group is to be defined.

Standard Input

When the -f "-" flag is specified, this command reads one or more node names from standard input.

Standard Output

When the -h flag is specified, this command's usage statement is written to standard output. All verbose messages are written to standard output.

Standard Error

All trace messages are written to standard error.

Examples

To define the communication group ComGrp1 for the peer domain ApplDomain and nodeA is defined and online to ApplDomain, run this command on nodeA:
```
mkcomg ComGrp1
```
To define the communication group ComGrp1 for the peer domain ApplDomain, using a sensitivity of 1 and period of 3, and nodeA is defined and online to ApplDomain, run this command on nodeA:
```
mkcomg -s 1 -p 3 ComGrp1
```
To define the communication group ComGrp1 for the peer domain ApplDomain, not using broadcast, using a priority of 3, and nodeA is defined and online to ApplDomain, run this command on nodeA:
```
mkcomg -x b -t 3 ComGrp1
```
To define the communication group ComGrp1 for the peer domain ApplDomain, not using broadcast, not using source routing, and nodeA is defined and online to ApplDomain, run the following command on nodeA:
```
mkcomg -x br ComGrp1
```
To define the communication group ComGrp1 for the peer domain ApplDomain, using a NIM path of /usr/sbin/rsct/bin/hats_nim, NIM parameters -l 5 to set the logging level, and nodeA is defined and online to ApplDomain, run this command on nodeA:
```
mkcomg -e /usr/sbin/rsct/bin/hats_nim -m "-l 5" ComGrp1
```
To define the communication group ComGrp1 for the peer domain ApplDomain, assign ComGrp1 to the network interface resource named eth0 on nodeB, and nodeA is defined and online to ApplDomain, run this command on nodeA:
```
mkcomg -i n:eth0:nodeB ComGrp1
```
To define the communication group ComGrp1 for the peer domain ApplDomain, assign ComGrp1 to the network interface resource that uses the subnet 9.123.45.678, and nodeA is defined and online to ApplDomain, run this command on nodeA:
```
mkcomg -S n:"Subnet == 9.123.45.678" ComGrp1
```

Location

/usr/sbin/rsct/bin/mkcomg: Contains the mkcomg command

Related Information

Commands: lscomg, lsrpdomain, lsrpnode, mkrpdomain, preprpnode, rmcomg, startrpdomain