module ietf-service-assurance {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-service-assurance";
prefix sain;
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data Types";
}
organization
"IETF OPSAWG Working Group";
contact
"WG Web:
WG List:
Author: Benoit Claise
Author: Jean Quilbeuf ";
description
"This module defines objects for assuring network services based on
their decomposition into so-called subservices, according to the
SAIN (Service Assurance for Intent-based Networking) architecture.
The subservices hierarchically organised by dependencies constitute
an assurance graph. This module should be supported by an assurance
agent, able to interact with the devices in order to produce a
health status and symptoms for each subservice in the assurance
graph.
This module is intended for the following use cases:
* Assurance graph configuration:
- subservices: configure a set of subservices to assure, by
specifying their types and parameters.
- dependencies: configure the dependencies between the
subservices, along with their type.
* Assurance telemetry: export the health status of the subservices,
along with the observed symptoms.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document
are to be interpreted as described in BCP 14 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.
Copyright (c) 2022 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Revised BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see the
RFC itself for full legal notices. ";
revision 2022-04-07 {
description
"Shorten prefix. Fix copyright.
Fix module description";
reference
"RFC xxxx: YANG Modules for Service Assurance";
}
revision 2022-01-04 {
description
"Explicitely model a missing value";
reference
"RFC xxxx: YANG Modules for Service Assurance";
}
revision 2021-06-28 {
description
"Made service-instance parameters mandatory.";
reference
"RFC xxxx: YANG Modules for Service Assurance";
}
revision 2020-01-13 {
description
"Added the maintenance window concept.";
reference
"RFC xxxx: YANG Modules for Service Assurance";
}
revision 2019-11-16 {
description
"Initial revision.";
reference
"RFC xxxx: YANG Modules for Service Assurance";
}
identity subservice-idty {
description
"Root identity for all subservice types.";
}
identity service-instance-idty {
base subservice-idty;
description
"Identity representing a service instance.";
}
identity dependency-type {
description
"Base identity for representing dependency types.";
}
identity informational-dependency {
base dependency-type;
description
"Indicates that symptoms of the dependency might be of interest
for the dependent, but the status of the dependency should not
have any impact on the dependent.";
}
identity impacting-dependency {
base dependency-type;
description
"Indicates that the status of the dependency directly impacts the
status of the dependent.";
}
grouping symptom {
description
"Contains the list of symptoms for a specific subservice.";
leaf id {
type string;
description
"A unique identifier for the symptom.";
}
leaf health-score-weight {
type uint8 {
range "0 .. 100";
}
description
"The weight to the health score incurred by this symptom. The
higher the value, the more of an impact this symptom has. If a
subservice health score is not 100, there must be at least one
symptom with a health score weight larger than 0.";
}
leaf description {
type string;
description
"Description of the symptom, i.e. text describing what the
symptom is, to be computer-consumable and be displayed on a
human interface. ";
}
leaf start-date-time {
type yang:date-and-time;
description
"Date and time at which the symptom was detected.";
}
leaf stop-date-time {
type yang:date-and-time;
description
"Date and time at which the symptom stopped being detected.";
}
}
grouping subservice-dependency {
description
"Represent a dependency to another subservice.";
leaf type {
type leafref {
path "/subservices/subservice/type";
}
description
"The type of the subservice to refer to (e.g. device).";
}
leaf id {
type leafref {
path "/subservices/subservice[type=current()/../type]/id";
}
description
"The identifier of the subservice to refer to.";
}
leaf dependency-type {
type identityref {
base dependency-type;
}
description
"Represents the type of dependency (i.e. informational,
impacting).";
}
// Augment here to add parameters specific to a new dependency-type.
// For instance, a specific dependency type could keep symptom
// whose health-score-weight is larger than a given value.
}
leaf assurance-graph-version {
type yang:counter64;
config false;
mandatory true;
description
"The assurance graph version, which increases by 1 for each new
version, after the changes (dependencies and/or maintenance
windows parameters) are applied to the subservice(s).";
}
leaf assurance-graph-last-change {
type yang:date-and-time;
config false;
mandatory true;
description
"Date and time at which the assurance graph last changed after the
changes (dependencies and/or maintenance windows parameters) are
applied to the subservice(s). These date and time must be more
recent or equal compared to the more recent value of any changed
subservices last-change";
}
container subservices {
description
"Root container for the subservices.";
list subservice {
key "type id";
description
"List of subservice configured.";
leaf type {
type identityref {
base subservice-idty;
}
description
"Type of the subservice, for instance device or interface.";
}
leaf id {
type string;
description
"Unique identifier of the subservice instance, for each
type.";
}
leaf last-change {
type yang:date-and-time;
config false;
description
"Date and time at which the assurance graph for this
subservice instance last changed, i.e. dependencies and/or
maintenance windows parameters.";
}
leaf label {
type string;
config false;
description
"Label of the subservice, i.e. text describing what the
subservice is to be displayed on a human interface.";
}
leaf under-maintenance {
type boolean;
default "false";
description
"An optional flag indicating whether this particular
subservice is under maintenance. Under this circumstance, the
subservice symptoms and the symptoms of its dependencies in
the assurance graph should not be taken into account.
Instead, the subservice should send a 'Under Maintenance'
single symptom.
The operator changing the under-maintenance value must set
the maintenance-contact variable.
When the subservice is not under maintenance any longer, the
under-maintenance flag must return to its default value and
the under-maintenance-owner variable deleted.";
}
leaf maintenance-contact {
when "../under-maintenance = 'true'";
type string;
mandatory true;
description
"A string used to model an administratively assigned name of
the resource that changed the under-maintenance value to
'true'.
It is suggested that this name contain one or more of the
following: IP address, management station name,
network manager's name, location, or phone number. In some
cases the agent itself will be the owner of an entry. In
these cases, this string shall be set to a string starting
with 'monitor'.";
}
choice parameter {
description
"Specify the required parameters per subservice type.";
container service-instance-parameter {
when "derived-from-or-self(../type,
'sain:service-instance-idty')";
description
"Specify the parameters of a service instance.";
leaf service {
type string;
mandatory true;
description
"Name of the service.";
}
leaf instance-name {
type string;
mandatory true;
description
"Name of the instance for that service.";
}
}
// Other modules can augment their own cases into here
}
leaf health-score {
type union {
type uint8 {
range "0 .. 100";
}
type enumeration {
enum missing {
value -1;
description
"Explictly represent the fact that the health score is
missing. This could be used when metrics crucial to
establish the health score are not collected anymore.";
}
}
}
config false;
description
"Score value of the subservice health. A value of 100 means
that subservice is healthy. A value of 0 means that the
subservice is broken. A value between 0 and 100 means that
the subservice is degraded.";
}
leaf symptoms-history-start {
type yang:date-and-time;
config false;
description
"Date and time at which the symptoms history starts for this
subservice instance, either because the subservice instance
started at that date and time or because the symptoms before
that were removed due to a garbage collection process.";
}
container symptoms {
description
"Symptoms for the subservice.";
list symptom {
key "start-date-time id";
config false;
description
"List of symptoms the subservice. While the start-date-time
key is not necessary per se, this would get the entries
sorted by start-date-time for easy consumption.";
uses symptom;
}
}
container dependencies {
description
"configure the dependencies between the subservices, along
with their types.";
list dependency {
key "type id";
description
"List of soft dependencies of the subservice.";
uses subservice-dependency;
}
}
}
}
}