github.com/sykesm/fabric@v1.1.0-preview.0.20200129034918-2aa12b1a0181/docs/source/whatsnew.rst

What's new in the v2.0 Beta release
===================================

The Beta release of Hyperledger Fabric v2.0 allows users to try out upcoming
features of Fabric v2.0. While the v2.0 release is not yet production ready,
the Beta is feature complete, meaning it includes all the features that are
expected to be delivered in the final v2.0 release.

Let’s take a peek at some of the highlights of Fabric v2.0....

Decentralized chaincode lifecycle
---------------------------------

Fabric v2.0 introduces decentralized governance for chaincode, with a new
process for installing a chaincode on your peers and starting it on a channel.
The new Fabric chaincode lifecycle allows multiple organizations to come to
agreement on the parameters of a chaincode, such as the chaincode endorsement
policy, before it can be used to interact with the ledger. The new model
offers several improvements over the previous lifecycle:

* **Multiple organizations must agree to the parameters of a chaincode**
  In the release 1.x versions of Fabric, one organization had the ability to
  set parameters of a chaincode (for instance the endorsement policy) for all
  other channel members, who only had the power to refuse to install the chaincode
  and therefore not take part in transactions invoking it. The new Fabric
  chaincode lifecycle is more flexible since it supports both centralized
  trust models (such as that of the previous lifecycle model) as well as
  decentralized models requiring a sufficient number of organizations to
  agree on an endorsement policy and other details before the chaincode
  ecomes active on a channel.

* **More deliberate chaincode upgrade process** In the previous chaincode
  lifecycle, the upgrade transaction could be issued by a single organization,
  creating a risk for a channel member that had not yet installed the new
  chaincode. The new model allows for a chaincode to be upgraded only after
  a sufficient number of organizations have approved the upgrade.

* **Simpler endorsement policy and private data collection updates**
  Fabric lifecycle allows you to change an endorsement policy or private
  data collection configuration without having to repackage or reinstall
  the chaincode. Users can also take advantage of a new default endorsement
  policy that requires endorsement from a majority of organizations on the
  channel. This policy is updated automatically when organizations are
  added or removed from the channel.

* **Inspectable chaincode packages** The Fabric lifecycle packages chaincode
  in easily readable tar files. This makes it easier to inspect the chaincode
  package and coordinate installation across multiple organizations.

* **Start multiple chaincodes on a channel using one package** The previous
  lifecycle defined each chaincode on the channel using a name and version
  that was specified when the chaincode package was installed. You can now
  use a single chaincode package and deploy it multiple times with different
  names on the same channel or on different channels. For example, if you’d
  like to track different types of assets in their own ‘copy’ of the chaincode.

* **Chaincode packages do not need to be identical across channel members**
  Organizations can customize a chaincode for their own use case, for example
  to perform different validations in the interest of their organization.
  As long as the required number of organizations endorse chaincode transactions
  with matching results, the transaction will be validated and committed to the
  ledger.  This also allows organizations to individually roll out minor fixes
  on their own schedules without requiring the entire network to proceed in lock-step.

Using the new chaincode lifecycle
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

For existing Fabric deployments, you can continue to use the prior chaincode
lifecycle with Fabric v2.0. The new chaincode lifecycle will become effective
only when the channel application capability is updated to v2.0.
See the :doc:`chaincode4noah` tutorial for complete details of the new
chaincode lifecycle.

External chaincode launcher
---------------------------

While chaincode is still run in a docker container by default in Fabric v2.0,
the external chaincode launcher feature empowers operators to build and launch
chaincode with the technology of their choice.

* **Eliminate Docker daemon dependency** Prior releases of Fabric required
  peers to have access to a Docker daemon in order to build and launch
  chaincode - something that may not be desirable in production environments
  due to the privileges required by the peer process.

* **Alternatives to containers** Chaincode is no longer required to be run
  in Docker containers, and may be executed in the operator’s choice of
  environment (including containers).

* **External builder executables** An operator can provide a set of external
  builder executables to override how the peer builds and launches chaincode.

* **Chaincode as an external service** Traditionally, chaincodes are launched
  by and then connect to the peer. It is now possible to run chaincode as
  an external service, for example in a Kubernetes pod, which a peer can
  connect to and utilize for chaincode execution. See :doc:`cc_service` for more
  information.

See :doc:`cc_launcher` to learn more about the external chaincode launcher feature.

Private data enhancements
-------------------------

Fabric v2.0 enables new patterns for working with and sharing private data,
without the requirement of creating private data collections for all
combinations of channel members that may want to transact. Specifically,
instead of sharing private data within a collection of multiple members,
you may want to share private data across collections at a transaction or
state key level with selected channel members. Each private data collection
may contain a single organization, or perhaps a single organization along
with a regulator or auditor.

Several enhancements in Fabric v2.0 make these new private data patterns possible:

* **Sharing and verifying private data** When private data is shared with a
  channel member who is not a member of a collection, or shared with another
  private data collection that contains one or more channel members (by writing
  a key to that collection), the receiving parties can utilize the
  GetPrivateDataHash() chaincode API to verify that the private data matches the
  on-chain hashes that were created from private data in previous transactions.

* **Collection-level endorsement policies** Private data collections can now
  optionally be defined with an endorsement policy that overrides the
  chaincode-level endorsement policy for keys within the collection. This
  feature can be used to restrict which organizations can write data to a
  collection. For example, you could utilize organization-specific private
  data collections to allow each organization to individually consent to state
  updates. This pattern is useful for implementing workflows that span individual
  transactions, for example to support voting or approval scenarios with data
  privacy and nonrepudiation.

* **Implicit per-organization collections** If you’d like to utilize
  per-organization private data patterns, you don’t even need to define the
  collections when deploying chaincode in Fabric v2.0.  Implicit
  organization-specific collections can be used without any upfront definition.

To learn more about the new private data patterns, see :doc:`private-data/private-data` (conceptual information)
for information about private data sharing and :doc:`private-data-arch` (reference information)
for documentation about private data collection configuration and implicit collections.

State database cache for improved performance on CouchDB
--------------------------------------------------------

* When using external CouchDB state database, read delays during endorsement
  and validation phases have historically been a performance bottleneck.

* With Fabric v2.0, a new peer cache replaces many of these expensive lookups
  with fast local cache reads. The cache size can be configured by using the
  core.yaml property ``cacheSize``.

Alpine-based docker images
--------------------------

Starting with v2.0, Hyperledger Fabric Docker images will use Alpine Linux,
a security-oriented, lightweight Linux distribution. This means that Docker
images are now much smaller, providing faster download and startup times,
as well as taking up less disk space on host systems. Alpine Linux is designed
from the ground up with security in mind, and the minimalist nature of the Alpine
distribution greatly reduces the risk of security vulnerabilities.

Sample test network
-------------------

The fabric-samples repository now includes a new Fabric test network. The test
network is built to be a modular and user friendly sample Fabric network that
makes it easy to test your applications and smart contracts. The network also
supports the ability to deploy your network using Certificate Authorities,
in addition to cryptogen.

For more information about this network, check out :doc:`test_network`.

Upgrading to Fabric v2.0
------------------------

While a Beta release is not an intended upgrade target for existing Fabric
deployments, there is nothing preventing you from testing an upgrade scenario
to get familiar with the process.

The upgrade docs have been significantly expanded and reworked, and now have a
standalone home in the documentation: :doc:`upgrade`. Here you'll find documentation on
:doc:`upgrading_your_components` and :doc:`updating_capabilities`, as well as a
specific look  at the considerations for upgrading to v2.0, :doc:`upgrade_to_newest_version`.

Release notes
=============

The release notes provide more details for users moving to the new release.
Specifically, take a look at the changes and deprecations that are being
announced with the new Fabric v2.0 release.

* `Fabric v2.0.0-beta release notes <https://github.com/hyperledger/fabric/releases/tag/v2.0.0-beta>`_.

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