mmcrcluster command

Availability

Available on all IBM Spectrum 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

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 Spectrum 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.

--ccr-enable

Enables the configuration server repository (CCR), which stores redundant copies of configuration data files on all quorum nodes. All GPFS administration commands, as well as file system mounts and daemon startups, work normally as long as a majority of quorum nodes are accessible. This is the default.

The CCR operation requires the use of the GSKit toolkit for authenticating network connections. As such, the gpfs.gskit package, which is available on all Editions, should be installed.

--ccr-disable

Indicates that the traditional primary/backup server-based configuration repository (non-CCR, earlier than GPFS 4.1) is to be used.

When using this option you must also specify a primary configuration server (-p option). It is suggested that you also specify a secondary GPFS cluster configuration server (-s option) to prevent the loss of configuration data in the event your primary GPFS cluster configuration server goes down. When the GPFS daemon starts up, at least one of the two GPFS cluster configuration servers must be accessible.

If your primary GPFS cluster configuration server fails and you have not designated a secondary server, the GPFS cluster configuration files are inaccessible, and any GPFS administration commands that are issued fail. File system mounts or daemon startups also fail if no GPFS cluster configuration server is available.

You are strongly advised to designate the cluster configuration servers as quorum nodes.

-p PrimaryServer

Specifies the primary GPFS cluster configuration server node used to store the GPFS configuration data. This node must be a member of the GPFS cluster. This option is necessary only when –ccr-disable is specified.

-s SecondaryServer

Specifies the secondary GPFS cluster configuration server node used to store the GPFS cluster data. This node must be a member of the GPFS cluster. This option is necessary only when –ccr-disable is specified.

-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 Spectrum 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, it is assumed to be a fully qualified domain name. Otherwise, to make the cluster name unique, the domain of the primary configuration server will be appended to the user-provided name.

If the -C flag is omitted, the cluster name defaults to the name of the primary GPFS cluster configuration server.

-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

A user's profiles must be installed in /var/mmfs/etc/. The profile file specifies GPFS configuration parameters with values different than the documented defaults. A user-defined profile must not begin with the string 'gpfs' and must have the .profile suffix.

%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