mmdelnode command

Removes one or more nodes from a GPFS™ cluster.

Synopsis

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

Availability

Available on all IBM Spectrum Scale™ editions.

Description

Use the mmdelnode command to delete one or more nodes from the GPFS cluster. You may issue the mmdelnode command on any GPFS node.

A node cannot be deleted if any of the following are true:

It is a primary or secondary GPFS cluster configuration server.
The node being deleted cannot be the primary or secondary GPFS cluster configuration server unless you intend to delete the entire cluster.

You can determine whether a node is the primary or secondary configuration server by issuing the mmlscluster command. If the node is listed as of the servers and you still want to delete it without deleting the cluster, first use the mmchcluster command to assign another node as the server.
It is defined as an NSD server.
The node being deleted cannot be defined as an NSD server for any disk unless you intend to delete the entire cluster.

You can determine whether a node is an NSD server for one or more disks by issuing the mmlsnsd command. If the node is listed as an NSD server and you still want to delete it without deleting the cluster, first use the mmchnsd command to assign another node as an NSD server for the affected disks.
If the GPFS state is unknown and the node is reachable on the network.
You cannot delete a node if both of the following are true:
- The node responds to a TCP/IP ping command from another node.
- The status of the node shows unknown when you use the mmgetstate command from another node in the cluster.
Note: You will probably be able to delete such a node if you physically power it off.
If the node is defined as a Transparent cloud tiering node. You can determine whether a node is a Transparent cloud tiering node by issuing the mmcloudgateway node list command. If the node is listed as the Transparent cloud tiering node, and you still want to delete it without deleting the cluster, first use the mmchnode command to disable the Transparent cloud tiering node role.
- If the node is a Transparent cloud tiering node, disable Transparent cloud tiering from the node by using the mmchnode --cloud-gateway-disable command, and then uninstall the Transparent cloud tiering rpms. Doing so ensures that the mmdelnode command does not fail on a Transparent cloud tiering node.

You must follow these rules when deleting nodes:

Unless all nodes in the cluster are being deleted, run the mmdelnode command from a node that will remain in the cluster.
Before you can delete a node, unmount all of the GPFS file systems and stop GPFS on the node to be deleted.
Exercise caution when shutting down GPFS on quorum nodes. If the number of remaining quorum nodes falls below the requirement for a quorum, you will be unable to perform file system operations. For more information, see Quorum.

Each GPFS cluster is managed independently, so there is no automatic coordination and propagation of changes between clusters like there is between the nodes within a cluster. This means that if you permanently delete nodes that are being used as contact nodes by other GPFS clusters that can mount your file systems, you should notify the administrators of those GPFS clusters so that they can update their own environments.

Results

Upon successful completion of the mmdelnode command, the specified nodes are deleted from the GPFS cluster.

Parameters

-a

Delete all nodes in the cluster.

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

Specifies the set of nodes to be deleted from the cluster.

For general information on how to specify node names, see Specifying nodes as input to GPFS commands.

This command does not support a NodeClass of mount.

Exit status

0: Successful completion.
nonzero: A failure has occurred.

Security

You must have root authority to run the mmdelnode 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 GPFS file system.

You may issue the mmdelnode command from any node that will remain in the GPFS cluster.

Examples

To delete all of the nodes in the cluster, issue this command:

mmdelnode -a

The system displays information similar to:

Verifying GPFS is stopped on all affected nodes ...
mmdelnode: Command successfully completed
mmdelnode: 6027-1371 Propagating the cluster configuration data to all
  affected nodes.  This is an asynchronous process.

To delete nodes k145n12, k145n13, and k145n14, issue this command:

mmdelnode -N k145n12,k145n13,k145n14