.. _agent-service-scoping:

Scoping
*******

Most keywords in a service configuration support a scoping syntax allowing each node agent to interpret the value differently.

Syntax
======

A scoped keyword is written as::

	<keyword>@<scope> = <value>

Supported scopes are:

* ``<nodename>``
  The hostname of the node we want the keyword value interpreted as ``<value>``

* ``nodes``
  The keyword value is interpreted as ``<value>`` on all service nodes

* ``drpnodes``
  The keyword value is interpreted as ``<value>`` on all service DRP nodes

* ``encapnodes``
  The keyword value is interpreted as ``<value>`` on all service encapsulated nodes

* ``flex_primary``
  The keyword value is interpreted as ``<value>`` on the flex service primary node

* ``drp_flex_primary``
  The keyword value is interpreted as ``<value>`` on the flex service disaster recovery primary node

Examples
--------

Use a Different Fs Type on DRP Nodes
++++++++++++++++++++++++++++++++++++

::

	[DEFAULT]
	nodes = n1 n2
	drpnode = n3

	[fs#1]
	type = ext4
	type@drpnodes = xfs
	...

Use a Different Nodes List at Encapsulated Level
++++++++++++++++++++++++++++++++++++++++++++++++

::

	[DEFAULT]
	nodes = n1 n2
	encapnodes = vm1
	nodes@encapnodes = vm1
	...

Disable a Resource on a Node
++++++++++++++++++++++++++++

::

	[DEFAULT]
	nodes = n1 n2
	drpnodes = n3

	[ip#backup]
	disable@n3 = true
	...

Precedence
==========

When a section has multiple definitions of the same keyword, the most specific takes precedence.

If multiple definitions of the same rank are found, the last takes precedence.

Examples
--------

::

	[DEFAULT]
	drpnodes = n3
	...

	[share#1]
	disable = true
	disable@drpnodes = false
	...

This resource is enabled on :c-node:`n3` because the generic disable is overriden by the more specific ``disable@drpnodes`` scoped definition.

::

	[DEFAULT]
	drpnodes = n3
	...

	[share#1]
	disable = true
	disable@drpnodes = false
	disable@n3 = true
	...

This resource is disabled on :c-node:`n3` because the generic disable and ``disable@drpnodes`` are overriden by the more specific ``disable@n3`` scoped definition.

::

	[DEFAULT]
	drpnodes = n3
	...

	[share#1]
	disable@n3 = true
	disable@n3 = false
	...

This resource is disabled on :c-node:`n3` because the last of the 2 same ranked scoped definition takes precedence.