mmcrcluster command

Availability

Available on all IBM Storage Scale editions.

Description

Use the mmcrcluster command to create a GPFS cluster.

Upon successful completion of the mmcrcluster command, the /var/mmfs/gen/mmsdrfs and the /var/mmfs/gen/mmfsNodeData files are created on each of the nodes in the cluster. Do not delete these files under any circumstances. For more information, see Quorum.

Parameters

-N NodeDesc[,NodeDesc...] | NodeFile

Specifies node descriptors, which provide information about nodes to be added to the cluster.

NodeFile

Specifies a file containing a list of node descriptors, one per line, to be added to the cluster.

NodeDesc[,NodeDesc...]

Specifies the list of nodes and node designations to be added to the GPFS cluster. Node descriptors are defined as:

NodeName:NodeDesignations:AdminNodeName:NodeComment

where:

NodeName

Specifies the host name or IP address of the node for GPFS daemon-to-daemon communication. For hosts with multiple adapters, see the IBM Storage Scale: Administration Guide and search on Using remote access with public and private IP addresses.

The host name or IP address must refer to the communication adapter over which the GPFS daemons communicate. Aliased interfaces are not allowed. Use the original address or a name that is resolved by the host command to that original address. You can specify a node using any of these forms:

• Short host name (for example, h135n01)
• Long, fully-qualified, host name (for example, h135n01.ibm.com)
• IP address (for example, 7.111.12.102). IPv6 addresses must be enclosed in brackets (for example, [2001:192::192:168:115:124]).

Regardless of which form you use, GPFS will resolve the input to a host name and an IP address and will store these in its configuration files. It is expected that those values will not change while the node belongs to the cluster.

NodeDesignations

An optional, "-" separated list of node roles:

• manager | client – Indicates whether a node is part of the node pool from which file system managers and token managers can be selected. The default is client.
• quorum | nonquorum – Indicates whether a node is counted as a quorum node. The default is nonquorum.

AdminNodeName

Specifies an optional field that consists of a node name to be used by the administration commands to communicate between nodes. If AdminNodeName is not specified, the NodeName value is used.

Note: AdminNodeName must be a resolvable network host name. For more information, see GPFS node adapter interface names.

You must provide a NodeDesc for each node to be added to the GPFS cluster.

NodeComment

Specifies an optional field that provides additional information on the node. The comment field might also be included in the NodeFile file as a parameter.

Note:

• Comments can only contain the following characters:
  0-9 A-Z a-z (space) # - . @ _
• While running a command with the -N option or using a NodeFile attribute to provide multiple node descriptors, all comments that include one or more spaces must be enclosed within single quotation marks (') or double quotation marks ("). Always use quotation marks with comments to avoid possible parsing errors.
• Comments must not begin with a -.
• Comments cannot be longer than 32 characters.
• Comments that include spaces at the beginning or end will have the spaces trimmed.

The comment field adds new data that is stored in the cluster configuration file and is available only to nodes running on IBM Storage Scale 5.1.4 or later for reading and configuring.

-r RemoteShellCommand

Specifies the fully-qualified path name for the remote shell program to be used by GPFS. The default value is /usr/bin/ssh.

The remote shell command must adhere to the same syntax format as the ssh command, but may implement an alternate authentication mechanism.

-R RemoteFileCopy

Specifies the fully-qualified path name for the remote file copy program to be used by GPFS. The default value is /usr/bin/scp.

The remote copy command must adhere to the same syntax format as the scp command, but may implement an alternate authentication mechanism.

--use-sudo-wrapper [sudo-user UserName]

Causes the nodes in the cluster to call the ssh and scp sudo wrapper scripts as the remote shell program and the remote copy program. For more information, see Running IBM Storage Scale commands without remote root login.

--sudo-user UserName

Specifies a non-root admin user ID to be used when sudo wrappers are enabled and a root-level background process calls an administration command directly instead of through sudo. The GPFS daemon that processes the administration command specifies this non-root user ID instead of the root ID when it needs to run internal commands on other nodes. For more information, see Root-level processes that call administration commands directly.

To disable this feature, specify the key word DELETE instead of a user name, as in the following example:

mmchcluster --sudo-user DELETE

-C ClusterName

Specifies a name for the cluster. If the user-provided name contains dots then the command assumes that the user-provided name is a fully qualified domain name. Otherwise, to make the cluster name unique, the command appends the domain of a quorum node to the user-provided name. The maximum length of the cluster name including any appended domain name is 115 characters.

If the -C flag is omitted, the cluster name defaults to the name of a quorum node within the cluster definition.

-U DomainName

Specifies the UID domain name for the cluster.

-A

Specifies that GPFS daemons are to be automatically started when nodes come up. The default is not to start daemons automatically.

-c ConfigFile

Specifies a file containing GPFS configuration parameters with values different than the documented defaults. A sample file can be found in /usr/lpp/mmfs/samples/mmfs.cfg.sample. See the mmchconfig command for a detailed description of the different configuration parameters.

The -c ConfigFile parameter should be used only by experienced administrators. Use this file to set up only those parameters that appear in the mmfs.cfg.sample file. Changes to any other values may be ignored by GPFS. When in doubt, use the mmchconfig command instead.

--profile ProfileName

Specifies a predefined profile of attributes to be applied. System-defined profiles are located in /usr/lpp/mmfs/profiles/. All the configuration attributes listed under a cluster stanza will be changed as a result of this command.

The following system-defined profile names are accepted:

• gpfsProtocolDefaults
• gpfsProtocolRandomIO

--port PortNumber

Specifies the IBM Storage Scale communication port number. The default port number is 1191.

%cluster:
[CommaSeparatedNodesOrNodeClasses:]ClusterConfigurationAttribute=Value
...
%filesystem:
FilesystemConfigurationAttribute=Value

Exit status

0

Successful completion.

nonzero

A failure has occurred.

Security

You must have root authority to run the mmcrcluster 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.

See also

Location