Composer Participants in Fabric - hyperledger-fabric

What is the role of Participants in Composer with an issued ID in Fabric?
When I issue a Business Network Card for a Composer Participant and connect to the Network how is this related to the Fabric architecture? Is the Participant an Application in Fabric or can he communicate over an Application?

If you are using a typical example/sample Fabric - When you Issue an ID (and create a Business Network Card) you are issuing an ID from the Fabric-CA.
With Composer, every connection you make to the Fabric uses a Business Network Card (and ID). This applies to every CLI command, every playground session, the REST API and your own applications.
Composer Concepts are described here.

Related

What is the best option for decentralised login into hyperledger fabric network?

I have a blockchain business network setup on hyperledger composer which interacts with Hyperledger Fabric. My business network is then exposed as a REST server which my angular application interacts with.
Im just wondering what is the best way to setup decetralised login functionality to my angular application?

Using more than one peer in Hyperledger Composer

I have recently deployed and started a business-network with Hyperledger Composer, I have only one peer (?) in which I have created the network and now I am using the rest-server for adding participant and doing transaction from an Android app to my personal blockchain and everything goes well.
So...Need I to configure one or more peers on my network? What's the utility of doing that?
I know that other blockchains needs a lot of peers for co-validating transactions and for maintaining a big scalability / distributed data; doesn't Hyperledger do it for me without adding more peers in my network?
If you have started with Hyperledger Composer you are probably using the 'standard' development Fabric with a Single Peer. This is a 'minimal' Fabric provided to get developers a fast start without the need to configure and deploy a Fabric. But you are correct Hyperleder Fabric can be configured for Multi Peer Multi Organisation distributed ledgers.
There are tutorials in the Fabric documentation for setting up a Fabric from scratch, and also this document covers a tool for extending the Fabric.

Hyperledger Fabric add new peers in different machine

I have completed this tutorial and successfully deployed a business network over what it seems to be a generic hyperledger fabric blockchain.
What i want to do now is to create a new peer in diffenrent machine but connected to the same blockchain. Can't find any information. Any help?
Thank you community!
To deploy hyperledger on a different machine you need to take advantage of docker swarm and overlay network. You can find the guide at
Deploying Hyperledger on Multiple Hosts
for the next question about extending your existing network by adding peers, follow Extending your network
I suggest you start looking at the hyperledger fabric documentation
http://hyperledger-fabric.readthedocs.io/en/latest/
You will need to understand about a hyperledger fabric network topology. There are many things you need to understand in order to understand how to configure a peer correctly and join it to a channel. The build your first network section will take you through creating a fabric network from scratch.

What kind of API needs to be exposed to allow outside access to a Hyperledger Fabric private network?

What kind of API needs to be exposed to allow outside access to a Hyperledger Fabric private network?
Are there any specifications describing this?
Thank you in advance for any enlightenment.
Hyperledger Fabric is designed to develep privated (permissioned) network. So, anyone who wants to acces to the network should have permissions for it. Hyperledger Fabric allows the acces to the network throught certificates, for wich it provides a CA. The CA allows you to control who are going to have acces to the netwotk. You register who you want.
Moreover, Hyperledger Fabric provides you a SDK wich makes it easy to use APIs to interact with a Hyperledger Fabric blockchain. More infor about it here.

Create one more peer node using hyperledger-composer

I implemented hyperledger composer tutorial and create a simple business network definition and deploy it on through composer and implement it's rest API's through composer-rest-server. Now I want to add one more peer to it on a different local machine which can access blockchain I created previously, so my question is How can I achieve that a different peer node (another local machine) connected to blockchain I created in the composer tutorial?
you can check the S/Overflow link provided by Ahmed Nasser relating to adding your peer to an existing Fabric network.
Once you have your Fabric network up and running, and all of your network configuration / resolution / docker configuration tested and working, you can come to Composer to define the connection info, such as adding additional peers (and therefore create the requisite business network cards that contain that info).
This single organisation tutorial can give you an idea of what's involved - it builds upon a Fabric network that was already created (a simple, one-peer Fabric blockchain Dev environment) ..see here -> https://hyperledger.github.io/composer/tutorials/deploy-to-fabric-single-org.html
It obviously refers to 'localhost' in this scenario - obviously, you are creating something on an IP network, so you will need IP addresses/ host resolution as appropriate.

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