Decision Guide for Adopting New Technology Agent Controller
Introduction
In TPTP 4.2, we introduced an Agent Controller based on new technology. This resulted in two Agent Controller API's (i.e. the
original Agent Controller, and the new technology Agent Controller). With TPTP 4.4, we are only shipping the new technology
Agent Controller. While some developers may want or need to continue using the original Agent
Controller, there are good reasons why most developers should begin migrating to
the new technology Agent Controller. This guide defines the differences
between the two Agent Controller versions, and gives developers decision
criteria for when to migrate to the new technology Agent Controller.
Change Taking Place in Agent Controllers
In TPTP 4.4 the new technology Agent Controller is supported on the Windows IA32, IPF, and EM64T platforms as well as on
the Linux IA32, IPF, and EM64T platforms. Additionally, the Integrated Agent Controller is now identical to the standalone new technology
Agent Controller. (Note: In TPTP 4.4, the Integrated Agent Controller is offered as a technical preview on 64-bit systems.)
The new technology Agent Controller supports backward compatibility and can be used with
earlier versions (TPTP 4.3.1 is recommended) of the original Agent Controller on the following platforms: Linux PowerPC/64-bit, Linux zSeries,
z/OS zSeries, OS/400 iSeries, AIX RISC System/6000, Solaris SPARC, and HP-UX RISC.
The new technology Agent Controller includes a backwards compatibility layer that allows
existing clients and agents to communicate with it in the same way they did with
its predecessor. Anyone familiar with the previous agent controller can install
a package with the new agent controller in it and
continue to use it as they
did before. Thus, while different platforms will contain different
implementations of the agent controller, all
platforms can continue to use the agent controller in the same fashion (when
using the old interfaces).
The new technology Agent Controller implements a new API that is richer and easier to
use. In addition to its remote application launching and file transfer services,
it provides the ability to dynamically discover agents (such as data
collectors), allows multiple instances of the agent controller to run, and
allows extensions of the command set using XML fragments. Using the new API, a
client application can dynamically discover which agents are installed on the
system where the Agent Controller is running. It can therefore adjust the
services it offers to a user according to what is available on the system the
user chooses to connect to. The new API is available in both C++ and Java
implementations.
Feature Comparison
The new technology Agent Controller design is a significantly different evolution of its
predecessor. While it includes a compatibility layer that maintains the old
APIs, adopters interested in additional functionality and performance
improvements in the future should be using the new APIs and removing any
dependence on the compatibility layer.
The new technology Agent Controller provides the same basic functionality for launching
applications, locally or remotely, as its predecessor. It performs the
platform-specific work of starting collector or service agents and setting up
command and data channels so that a client can communicate with the agents. The
goal of the redesign is to make the agent controller flexible so that it can be
easily extended to meet more needs. One such change was replacing the use of
binary and custom commands for exchanges between clients, agent controller, and
agents to standardizing on the use of XML fragments for all commands. Agent
writers can easily define their own command set without impacting the agent
controller and clients can create and send all commands in a uniform fashion.
Another change towards flexibility was implementing the communication layers as
replaceable units so that others can drop in their own version to meet a
particular platform or performance need.
With the new technology Agent Controller comes new programming interfaces for both
client and agent writers. These API’s are available in both C++ and Java,
whereas only Java was available in the past. The concept of agents and
collectors (specialized agents with the purpose of collecting data) have been
formalized into classes of objects with base implementations that do the
standard tasks expected of an agent or collector agent, so that the focus of
development is on the unique purpose of the agent.
There are differences in the services available through the old and new agent
controller APIs. Those features that are currently only
available through the
old API are expected to be added to the new API in
coming releases. (For information on features going into a particular release,
please refer to the release plans which are developed and posted on the TPTP
home page
https://www.eclipse.org/tptp).
Additional functionality available through the new APIs:
-
Runtime
Discoverable Agents – Using the new API a client application can obtain a
list of all the agents installed on the system that the new Agent Controller
is executing on. The Agent Controller will automatically launch an agent
that is not running, if the client wants its services.
-
Extensible Agent and Client APIs – Client and agent applications can be
developed using either the C++ or Java versions of the APIs. The boiler
plate code has already been provided as a foundation on which to build
custom applications.
-
Specialized, Bi-directional Communication Channels – Commands and data
flow over distinct channels, so a command can interrupt the flow of data or
not – as the agent writer chooses. Also, both commands and data can flow
either direction. An agent can notify the client of some event without it
being a reply to a command. Additionally, going through firewalls is
improved as known ports can be used and multiplexing of commands and data on
the same channel is not required.
-
Concurrent Agent Controller Execution - By providing unique
configuration information for the communication (transport) layers for each,
multiple Agent Controllers can run at the same time.
Functionality only available through the old APIs:
-
Extended File Transfer Services - The file transfer services
offered through the old API are richer, including support for a progress monitor
among others. The new file transfer agent supports just the basic put, get, and
delete of files at this time.
-
Secure Connection with Agent Controller – When connecting with the
Agent Controller using the old API there is a configuration option that requires
authentication before the Agent Controller can be used.
-
Dynamic Discovery of Peer Agent Controller – This is a rather
specialized functionality that allows an agent to request that it be monitored
by an Agent Controller that is different from the one that started it.
Choosing An Agent Controller Interface
If you are implementing an agent application that will
interact with the Agent Controller, you have a choice of using the new API or
the old API. Following are the things to consider when making that choice.
-
Platform Coverage – In TPTP 4.4, the new API is available on
Windows IA32/EM64T/IPF and Linux IA32/EM64T/IPF platforms. The old API is
available on Windows IA32/EM64T/IPF, Linux IA32/EM64T/IPF, AIX RISC System/6000, HP-UX RISC, Linux PowerPC/64-bit, Linux zSeries,
OS/400 iSeries, Solaris SPARC, and Z/OS zSeries.
Be sure to check the TPTP published release plans (https://www.eclipse.org/tptp)
to see when these platforms are expected to support the new API.
If you don’t see the coverage you need with the new API, you will need to
use the old API. (Note: The old API is not deprecated at this time, but may be deprecated once new API platform coverage
is equivalent to, or better than, that provided by the old API.)
-
Integration with TPTP Tools, Analysis and UI Frameworks: In 4.2,
the TPTP tools and higher level frameworks are integrated with the old API. If
you intend to use these frameworks, then you will need to use the old Agent
Controller API [or plan on doing substantial changes to adapt these frameworks
to use the new API]. In the future, we expect to extend the new API on the
client side to support agents using either old API or new API. If you are
writing a new client application that does not rely on the existing framework
then using the new API is the better choice, but you still need to consider the
agents it will communicate with. Clients that use the new API that want to work
with an agent that uses the old API need to be constructed with care (start by
seeking advice from the Data Communication and Collections team). Communication
channels for old agents and new agents can co-exist, so it is possible to write
a single client to do both as long as the client uses appropriately formatted
commands for each.
-
Integrated Agent Controller: Unlike its predecessors, the Integrated
Agent Controller in TPTP 4.4 does not run in the same process as the Eclipse Workbench. The
new IAC actually runs as a separate process, which gets assigned more
memory allocations, allowing it to profile bigger applications than the old IAC.
It is more convenient to use when there is no need for launching agents and applications on remote systems.
This version of the Integrated Agent Controller is identical to the new technology Agent Controller and consequently uses
the new API.
If you are limited by platform support of the old or new
API, check the TPTP published plan for the upcoming release (https://www.eclipse.org/tptp)
to find out when the new Agent Controller will be available on the platforms of
interest, before choosing to write to the old interface. You can influence the
order in which platforms are supported by submitting enhancement requests to
bugzilla naming the platforms of interest and time frame needed, or simply
voting for the enhancement of interest if a bugzilla already exists.
SDKs
SDKs for each platform are available from the Downloads page at
https://www.eclipse.org/tptp/home/downloads/downloads.php
.
Reference documents
C++ and Java reference specifications for the new API can be accessed
through the
TPTP Data Collection Framework
document. Refer to the
Extending the Agent Controller and Integrated Agent Controller document to find the
Java reference specification for the old API.
Copyright (C) 2005, 2007 Intel Corporation.
