Extending OpenStack Settings

Extending OpenStack Settings

Each release has a list of OpenStack settings that can be customized. The settings configuration is stored in the attributes_metadata.editable release section in the openstack.yaml file.

Settings are divided into groups. Each group should have a metadata section with the following attributes:

  toggleable: true
  enabled: false
  weight: 40
  group: "security"
  • toggleable defines an ability to enable/disable the whole setting group on UI (checkbox control is presented near a setting group label).
  • enabled indicates whether the group is checked on the UI.
  • weight defines the order in which this group is displayed on the tab.
  • restrictions: see restrictions.
  • group identifies which subtab on the UI this group of settings will be displayed on.

Other sections of a setting group represent separate settings. A setting structure includes the following attributes:

  value: "tcp"
  label: "Syslog transport protocol"
  description: ""
  weight: 30
  type: "radio"
    - data: "udp"
      label: "UDP"
      description: ""
        - "cluster:net_provider != 'neutron'"
    - data: "tcp"
      label: "TCP"
      description: ""
    source: "^[A-z0-9]+$"
    error: "Invalid data"
  min: 1
  max: 3
  group: "logging"
  • label is a setting title that is displayed on UI.
  • weight defines the order in which this setting is displayed in its group. This attribute is desirable.
  • type defines the type of UI control to use for the setting. The following types are supported:
    • text - single line input
    • number - number input
    • password - password input
    • textarea - multiline input
    • checkbox - multiple-options selector
    • radio - single-option selector
    • select - drop-down list
    • hidden - invisible input
    • file - file contents input
    • text_list - multiple sigle-line text inputs
    • textarea_list - multiple multi-line text inputs
  • regex section is applicable for settings of “text” type. regex.source is used when validating with a regular expression. regex.error contains a warning displayed near invalid field.
  • restrictions: see restrictions.
  • description section should also contain information about setting restrictions (dependencies, conflicts).
  • values list is needed for settings of “radio” or “select” type to declare its possible values. Options from values list also support dependencies and conflcits declaration.
  • min is used for setting the “number”, “text_list” or “textarea_list” type. For the “number” type, “min” declares the minimum input number value. For the “text_list” and “textarea_list” types, it declares the minimum list length for the setting.
  • max is used for setting the “number”, “text_list”, or “textarea_list” type. For the “number” type, “max” declares the maximum input number value. For the “text_list” and “textarea_list” types, it declares the maximum list length for the setting.
  • group specifies which subtab on the UI settings/networks page this setting will be displayed on. Inherited from the metadata section if not provided. The following values are supported by UI:
    • general - main cluster settings
    • security - security settings
    • compute - common compute settings
    • network - network settings (are collected on the separate Networks tab)
    • storage - storage settings
    • logging - logging settings
    • openstack_services - OpenStack services settings (Additional Components subtab)
    • other - other settings (everything out of the above list)


Restrictions define when settings and setting groups should be available. Each restriction is defined as a condition with optional action, message, and strict:

  - condition: "settings:common.libvirt_type.value != 'kvm'"
    message: "KVM only is supported"
  - condition: "not ('experimental' in version:feature_groups)"
    action: hide
  • condition is an expression written in Expression DSL. If returned value is true, then action is performed and message is shown (if specified).

  • action defines what to do if condition is satisfied. Supported values are disable, hide and none.``none`` can be used just to display message. This field is optional (default value is disable).

  • message is a message that is shown if condition is satisfied. This field is optional.

  • strict is a boolean flag which specifies how to handle non-existent keys in expressions. If it is set to true (default value), exception is thrown in case of non-existent key. Otherwise, values of such keys have a null value. Setting this flag to false is useful for conditions which rely on settings provided by plugins:

      - condition: "settings:other_plugin == null or settings:other_plugin.metadata.enabled != true"
        strict: false
        message: "Other plugin must be installed and enabled"

There are also short forms of restrictions:

  - "settings:common.libvirt_type.value != 'kvm'": "KVM only is supported"
  - "settings:storage.volumes_ceph.value == true"

Expression Syntax

Expression DSL can describe arbitrarily complex conditions that compare fields of models and scalar values.

Supported types are:

  • Number (123, 5.67)

  • String (“qwe”, ‘zxc’)

  • Boolean (true, false)

  • Null value (null)

  • ModelPath (settings:common.libvirt_type.value, cluster:net_provider)

    ModelPaths consist of a model name and a field name separated by ”:”. Nested fields (like in settings) are supported, separated by ”.”. Models available for usage are “cluster”, “settings”, “networking_parameters” and “version”.

Supported operators are:

  • ==. Returns true if operands are equal:

    settings:common.libvirt_type.value == 'qemu'
  • !=. Returns true if operands are not equal:

    cluster:net_provider != 'neutron'
  • in. Returns true if the right operand (Array or String) contains the left operand:

    'ceph-osd' in release:roles
  • Boolean operators: and, or, not:

    cluster:mode == "ha_compact" and not (settings:common.libvirt_type.value == 'kvm' or 'experimental' in version:feature_groups)
  • Parentheses can be used to override the order of precedence.

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