mmchnode command

Availability

Available on all IBM Spectrum Scale™ editions.

Description

Use the mmchnode command to change one or more attributes on a single node or on a set of nodes. If conflicting node designation attributes are specified for a given node, the last value is used. If any of the attributes represent a node-unique value, the -N option must resolve to a single node.

Do not use the mmchnode command to change the gateway node role while IO is happening on the fileset. Run the flushpending command to flush any pending messages from queues before running the mmchnode command for the gateway node role changes.

Parameters

-N {Node[,Node...] | NodeFile | NodeClass}

Specifies the nodes whose states are to be changed.

For general information on how to specify node names, see Specifying nodes as input to GPFS commands in the IBM Spectrum Scale: Administration and Programming Reference.

-S Filename | --spec-file=Filename

Specifies a file with a detailed description of the changes to be made. Each line represents the changes to an individual node and has the following format:

node-identifier change-options

change-options

A blank-separated list of attribute[=value] pairs. The following attributes can be specified:

--admin-interface={hostname | ip_address}

Specifies the name of the node to be used by GPFS™ administration commands when communicating between nodes. The admin node name must be specified as an IP address or a hostname that is resolved by the host command to the desired IP address. If the keyword DEFAULT is specified, the admin interface for the node is set to be equal to the daemon interface for the node.

--client

Specifies that the node should not be part of the pool of nodes from which cluster managers, file system managers, and token managers are selected.

--ces-enable

Enables Cluster Export Services (CES) on the node.

--ces-disable

Disables CES on the node.

--ces-group=Group[,Group...]

Adds one or more groups to the specified nodes.

--noces-group=Group[,Group...]

Removes one or more groups from the specified nodes.

--cnfs-disable

Disables the CNFS functionality of a CNFS member node.

--cnfs-enable

Enables a previously-disabled CNFS member node.

--cnfs-groupid=groupid

Specifies a failover recovery group for the node. If the keyword DEFAULT is specified, the CNFS recovery group for the node is set to zero.

For additional information, refer to "Implementing a clustered NFS using GPFS on Linux" in the IBM Spectrum Scale: Advanced Administration Guide.

--cnfs-interface=ip_address_list

A comma-separated list of host names or IP addresses to be used for GPFS cluster NFS serving.

The specified IP addresses can be real or virtual (aliased). These addresses must be configured to be static (not DHCP) and to not start at boot time.

The GPFS daemon interface for the node cannot be a part of the list of CNFS IP addresses.

If the keyword DEFAULT is specified, the CNFS IP address list is removed and the node is no longer considered a member of CNFS.

If adminMode central is in effect for the cluster, all CNFS member nodes must be able to execute remote commands without the need for a password.

For additional information, refer to "Implementing a clustered NFS using GPFS on Linux" in the IBM Spectrum Scale: Advanced Administration Guide.

--daemon-interface={hostname | ip_address}

Specifies the host name or IP address to be used by the GPFS daemons for node-to-node communication. The host name or IP address must refer to the communication adapter over which the GPFS daemons communicate. Alias interfaces are not allowed. Use the original address or a name that is resolved by the host command to the original address.

Before you specify this option, you must stop GPFS on all the nodes in the cluster. You cannot use the keyword DEFAULT with this option.

You cannot specify the --daemon-interface option for a quorum node if CCR is enabled. Temporarily change the node to a nonquorum node. Then run the mmchnode command with the --daemon-interface option against the nonquorum node. Finally, change the node back into a quorum node.

--gateway | --nogateway

Specifies whether the node is to be designated as a gateway node or not.

--manager

Designates the node as part of the pool of nodes from which file system managers and token managers are selected.

--nonquorum

Designates the node as a non-quorum node. If two or more quorum nodes are downgraded at the same time, GPFS must be stopped on all nodes in the cluster. GPFS does not have to be stopped if the nodes are downgraded one at a time.

--perfmon | --noperfmon

Specifies whether the node is to be designated as a perfmon node or not.

--nosnmp-agent

Stops the SNMP subagent and specifies that the node should no longer serve as an SNMP collector node. For additional information see the topic "GPFS SNMP support" in the IBM Spectrum Scale: Advanced Administration Guide.

--quorum

Designates the node as a quorum node.

Note: If you are designating a node as a quorum node, and adminMode central is in effect for the cluster, you must ensure that GPFS is up and running on that node (mmgetstate reports the state of the node as active).

--snmp-agent

Designates the node as an SNMP collector node. If the GPFS daemon is active on this node, the SNMP subagent will be started as well. For additional information see the topic "GPFS SNMP support" in the IBM Spectrum Scale: Advanced Administration Guide.

Exit status

0

Successful completion.

nonzero

A failure has occurred.

Security

You must have root authority to run the mmchnode command.

The node on which the command is issued must be able to execute remote shell commands on any other node in the cluster without the use of a password and without producing any extraneous messages. For more information, see Requirements for administering a file system in IBM Spectrum Scale: Administration and Programming Reference.

See also

Location