Module 1: ConfD Technical Introduction

1©2015 Tail-f Systems all rights reserved February 13, 2015

ConfD Technical Introduction


What is ConfD?

ConfD provides a data-model driven management plane framework which provides a variety of standards-based northbound management interfaces for use in building network elements:

Physical Network DevicesVirtual Network Devices

(VNF in NFV)Network Appliancesetc.


How is ConfD different?

SNMP agentCLI engineNETCONF server…

Protocol Focused Agents

Stove-pipeFeature-lagJust the protocol layer

Data-model drivenAny protocol

ConfD

All protocolsNo feature lagCore engine


ConfD Overview

Network

Element

NETCONF SNMP REST CLI Web

Database Data Provider API

Managed Object API

Management Agent API

OSS/BSS

MO MOMO

ConfD Core Engine

MO

External

DatabaseOperational

Data

MO


ConfD Overview

Network

Element


CDB

DatabaseData Provider API

CDB API


OSS/BSS

App AppApp

ConfD Core Engine

App

External

DatabaseOperational

Data

App


Auto-rendered management interfaces and data schema

YANGData Models


True Model-Driven

• Information models (UML, SID, …)

• Important for communication between domain experts

• Needs “mapping” to data-models

• Data Models

• Concrete

• Means something in reality

• Tail-f story

• Core-engine driven by data-models

• No stubs!

• Translators to information models, UML, SID, …

• You can execute with the data-model only

• CLI

• WebUI

• Database

• …

• YANG – RFC 6020

• IETF greybeards

• Concrete, precise, semantically rich

• Clarity – “anyone” can read

• Precision – self documenting

• Modular data models

• Extensible language

• Code generation


YANG Example

module sys {

namespace "urn:sys";

prefix sys;

import tailf-common {

prefix tailf;

}

typedef interface-name {

type string {

length "min .. 30";

pattern "[A-Za-z][^/:.]*";

}

}


YANG Example (cont.)

container sys {

container numbers {

leaf odd {

type int32;

default 1;

must "(. mod 2) = 1" {

error-message "can only be an odd number";

tailf:dependency ".";

}

} }

list ifc {

key name;

max-elements 1024;

leaf name {

type interface-name;

}

leaf enabled {

type boolean;

default true;

}


YANG Example (cont.)

list labels {

key string;

max-elements 16;

description

"A label is an alphanumeric string assigned to an

interface. Each interface can have many labels. The

purpose here is simply to show a must validation that

requires the labels to be unique for all interfaces.”; leaf string {

type string {

length "1..31";

pattern "[a-zA-Z][a-zA-Z0-9_-]*";

}

must "not(/sys:sys/sys:ifc[name = current()])" {

error-message

"A label can not be the same as an interface name";

tailf:dependency "/sys/ifc/name";

}

must "count(/sys/ifc/labels[string = current()]) = 1" {

error-message "All labels must be unique";

tailf:dependency ".";

}

}


ConfD OverviewConfD


ConfD Core Engine

CDB

Database

Transaction Management

Session Management / Authentication

Role-based Access Control

Audit Trailing

Redundancy / Replication

Validation (syntactic and semantic)

Rollback Management

Upgrades and Downgrades

Data Provider API CDB API


OperationalData

Counters

Alarms

StatisticsMO

External

Database Operational

Data

MO

Validation

API

Authentication

API

Radius

PAM

TACACS

Others

Operational Data

Operational

Data API

App AppApp


ConfD Overview

API lib

App

IPC (via TCP Sockets)

Application Blades

Management Blade

= Unix/Linux process

NETCONF

ConfD

SNMP REST CLI WEB

API lib

App

API lib

App

API lib

App

API libraries available for: C, Erlang, Java, and Python (limited coverage)


High Availability

NETCO

NF

Management Blade

ConfD

Configuration

Datastore

SN

MP

REST

CLI

Web

“Standby”

NETCO

NF

Management Blade

ConfD

Configuration

Datastore

SN

MP

REST

CLI

Web

Data Replication

“Active”

ApplicationBlade


Integrated Database (CDB)


CDBDatabase

Data Provider API

CDB API


App AppApp

ConfD Core Engine

App

External DatabaseOperational

Data

App

• Hierarchical database

• ACID test compliant

• Atomicity, consistency, isolation, durability

• Fast, lightweight, fault-tolerant

• Compact binary XML format

• Memory resident with journal in persistent storage

• Schema automatically derived from YANG

• Supports 1:N data replication

• Supports automatic schema version up/downgrades

• CDB can hold some or all data

• Configuration data and/or Operational data

• External database can be used in addition to or instead of

• Automatic loading of initial data

• Applications read data, then subscribe to relevant configuration changes

• Subscription notifications with priority level ordering

• Multiple datastores per NETCONF standards

• Startup, running, candidate, operational


NETCONF Interface

• IETF RFC 4741/6241

• Full implementation

• All mandatory and all optional capabilities

• RFC 4742/6242 NETCONF over SSH

• Streams XML over SSH

• Separates operational datafrom configuration

• Distributed transactions

• RFC 5277 NETCONF notifications

• Support included for various IETF standardized YANG data models

<get-config>

<edit-config>

<delete-config>

<lock>

<unlock>

<get>

<close-session>

<kill-session>

<commit>

<discard-changes>

:writeable-running

:candidate

:confirmed-commit

:rollback-on-error

:validate

:startup

:URL

:XPath

NETCONF OPERATIONS

NETCONF CAPABILITIES


CDBDatabase

Data Provider API

CDB API


App AppApp

ConfD Core Engine

App


Data

App


SNMP Agent

• SNMP machine interface

• Any combination of v1, v2c, v3

• Supports all operations

• Send SNMP notifications (traps)

• MIBs implemented by ConfD include:

• RFC-3411 (SNMP-FRAMEWORK-MIB)

• RFC-3414 (USM)

• RFC-3415 (VACM)

• RFC-3418 (SNMPv2-MIB)

• MIB to YANG translator

• YANG to MIB translator


CDBDatabase

Data Provider API

CDB API


App AppApp

ConfD Core Engine

App


Data

App


Command Line Interface (CLI)

• Auto rendering of three CLI styles:

• Cisco – XR style

• Cisco – legacy IOS style

• Juniper – JUNOS style

• Rich editing with tab-completion for commands,static elements and dynamic instances

• History, hints, help

• Extensible with custom/external commands, wizards

• Typically runs over SSH


CDBDatabase

Data Provider API

CDB API


App AppApp

ConfD Core Engine

App


Data

App


Web

• JSON RPC API

• Access data

• Run transactions and rollbacks

• Do validation

• Execute actions

• Access data model schema information

• Customer choice of toolsets and frameworks

• Preserve existing Web content

• Example of how to implement an auto-rendered Web UI provided

• Supports HTTP and HTTPS


REST

• Relies on verbs of transport layer:

• HTTP 1.1

• GET : get resources

• Selectors : shallow, deep

• PUT : replace existing resource

• POST : create resource

• DELETE : delete resource

• PATCH (RFC5789) : modify existing resource

• HEAD, OPTIONS

• Stateless, client-server

• Hyperlinked, just like the web

• XML or JSON as data containers

• Links to available data-stores and operations


CDBDatabase

Data Provider API

CDB API


App AppApp

ConfD Core Engine

App


Data

App

$curl –u admin:admin –s http://localhost:8008/api

• /api/running

• /api/candidate

• /api/operations

• /api/operational

• /api/rollback


Why ConfD

Make your customer happy

Make your device

• Manageable

• Programmable

• Standards -compliant

Save time

• Render management interfaces

• Model-driven

• Iterative development

• NETCONF, CLI, SNMP, REST, Web

• Transactions and rollbacks

• Validations

• Configuration and monitoring

• No feature lag

• Core components

• Embedded database

• Domain-specific functions

• Rich APIs

• Well-tested, 70+ customers



Data Provider API

A transaction can be viewed as a conceptual state machine

• Phases of a transaction correspond to states

• API transaction callback function invocations are state transitions

Start

Read

Prepare

Write

Validate

Abort Commit

init()

commit()

prepare()

write_start()

trans_lock()trans_unlock()

finish()

abort()

finish()

finish()

get_next()

get_elem()

finish()finish()

set_elem()

create()

remove()

get_next()

get_elem()

Date post:	16-Jul-2015
Category:	Technology
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Module 1: ConfD Technical Introduction

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