Sections. The option exists to organize cluster settings into sections. A configuration file section is identified by a unique name within square brackets ([section-name]) containing settings logically related to each other.

Guidelines: Follow these guidelines to manage configuration files in storage clusters:

1. Set the appropriate configuration settings.

2. If upgrading, add, remove, or adjust the settings and values as directed.

3. Use new and empty sections properly.

Scope of Settings

Each setting has one of two scopes:

• cluster-wide: Used across the entire cluster. This is the default scope, so it is not specified in the reference. Every cluster-wide setting must be identical for all nodes in the node or cluster configuration file. 

• node-specific: Specific to each node (chassis or virtual machine). These are the exceptions to the majority (cluster-wide), so they are flagged in the reference. Each cluster node can have a different value.

Qualified versus Unqualified Settings

Swarm supports both qualified and unqualified configuration settings.

• An unqualified setting (such as corporate) must be contained in the designated [section], in the empty [] section, or in a configuration file with no sections (or the empty section).

• A qualified setting (such as networks.corporate) is the name of the section, a period, and the unqualified setting name.

A configuration file can have a mixture of unqualified and fully qualified settings, provided the settings are in the proper sections or the configuration file has no sections (or the empty section).

Organizing Settings by Section

In Swarm, sections are optional (unless using new, unqualified names). Sections must be used properly if using them.

New Sections

Errors result and Swarm does not start if placing unrelated parameters or an old parameter name in any section. The following parameter is not valid:

The following setting is valid:

Empty Sections

The empty section [] (empty set of square brackets) is a special container clearing any section that may have preceded it. The following setting is valid:

Formatting Settings

All configuration files contain the name-and-value pairs for setting configuration options.

• The format for these pairs is name = value.

• Whitespace before the name, between the name and =, and between = and the value is ignored.

• Quotes (") are not stripped from values.

• Blank lines and lines beginning with a hash tag (#) are ignored. If this tag appears within the parameter value (anywhere after = ), it is part of the option's value field and not a comment.

Upgrading a Configuration File

Update a node or cluster configuration file by placing new settings, renamed settings, and sections at the end of the existing configuration file. This prevents conflicts with settings located at the beginning of the file.
Use the following guidelines when adding new settings:

• Add new configuration settings in sections or a fully qualified format. Adding new settings at the end of the configuration file avoids problems preventing the cluster from booting. Place it at the end of the node or cluster configuration to add the new encoding setting. The new setting does not affect any settings before it. The cluster boots normally and nothing else in the configuration file needs to be modified.

• Rename existing settings. Renamed settings are deprecated and are removed eventually in a future release.
  See https://perifery.atlassian.net/wiki/spaces/public/pages/2443811601.

• Add sections to the configuration file, verifying all settings are in the correct sections. All settings after a section placed in the node or cluster configuration file must either be placed in respective sections or must be fully qualified.
  See https://perifery.atlassian.net/wiki/spaces/public/pages/2443811510.