I am following the two org hyperledger fabric example. After starting the network I can see 4 extra dev peers running along with 4 peers(2 peers per org) in docker containers. But in configuration I gave only 4 peers. I am not understanding how the other 4 dev peers got created and whats their purpose.
A specific 'Chain Code Container' gets created for each peer running the Business Network. E.g. dev-peer0.org1.example.com-tutorial-network-0.16.3.... These containers are started and restarted automatically.
Chaincodes are instantiated in a separate container. When you instantiate a chaincode in a peer ,container for that chaincode is created.
If you instantiate 3 chaincode in a peer0 then you will see 3 containers with name like dev-peer0.mycc1, dev-peer0.mycc2,dev-peer0.mycc3
More details about this process can be found in an offical document mentioned below.(search text "dev-peer")
https://github.com/hyperledger/fabric/blob/release-1.4/docs/source/build_network.rst
Related
Here is the log of Hyperledger Fabric test network. There are 2 peer node(peer0.org1.example.com & peer0.org2.example.com) and 2 orderer node(orderer.example.com & orderer2.example.com).
My question is what 「writeBlock」,「StoreBlock」，「Validate」「commit」stage actually does? I know that at 「propose」stage, a chosen orderer(in this case, orderer.example.com) will create a block and then send the created block to other orderer such as orderer2.example.com. However, I don't understand what orderers does at「writeBlock」stage. Do they sign the created block at 「writeBlock」stage? Next, peer nodes received the block from who? orderer.example.com or orderer2.example.com? In my guess, I think it's from orderer.example.com but I'm not sure.
I don't understand what orderers does at「writeBlock」stage.
I'm not sure about those stages (writeBlock looks self-explanatory). I don't know about "StoreBlock", it isn't mentioned in the official docs. I'm wondering which Fabric version you are using.
Next, peer nodes received the block from who?
In a RAFT network you have a leader/follower model. You can think of a leader peer as an entry point/doorman for all communication coming from the ordering nodes. An ordering node sends blocks to the leading peer(s) of each organization; the leading peer is then responsible for distributing those blocks to other peers belonging to the same organization. Distribution is done using gossip protocol.
Hyperledger Fabric is a complex system, with many components and a lot of moving parts.
The log that you are referring to is the log of the orderer node - orderer.example.com. It's a part of the Fabric test network. You can see what's happening in detail by looking at the logs of other Fabric components, such as peer node logs.
The Fabric network has a set of orderer nodes, which are responsible for ordering the transactions and creating blocks in the blockchain.
The orderer nodes are configured to use a consensus algorithm (such as Solo or Kafka) to achieve a consensus about the order of the transactions.
A Fabric network has a set of peer nodes, which are responsible for executing the chaincode (smart contracts) and catching and validating the transactions.
The Fabric test network consists of one orderer node, which is configured to use Solo consensus algorithm. This orderer node is orderer.example.com.
The Fabric test network consists of two peer nodes, which are peer0.org1.example.com and peer0.org2.example.com.
The log that you are referring to is the log of the orderer node - ord
I'm trying to add an organisation to a channel following the documentation tutorial. Everything goes all right but the last command, the one to join the new organisation to the channel.
peer channel join -b channel-artifacts/channel1.block
I've read that this indicates that the peers have already joined the channel, but that's not the case. When I try to deploy a contract, for example, it can't be installed on the peers of the new organisation.
The problem was that some docker volumes were kept after restarting the network. So I shut down the network and ran the following command to delete the all docker volumes in the system.
docker system prune --volumes -f
After restarting, the organisation could be joined to the networks without errors.
What steps are required in order to add an endorsing peer to a blockchain network (in hyperledger-fabric)? What about promoting a committing peer in an endorsing one?
Should I just alter files crypto-config.yaml and configtx.yaml by adding the new peer?
I am using the fabcar example from the fabric-samples repo (https://github.com/hyperledger/fabric-samples), so should I change the docker-compose(-cli).yaml also? When starting the network with startFabric.sh script, should I just install chaincode on the new peers, or are other steps requires also?
I tried it with just installing a chaincode on the new peers, however I got an error stating that "... Consortium was not met when instantiating the chaincode ..."
Edit:
I was able to install the chaincode on all four peers and instantiate it on the channel. Initial non-query transaction is successful and another one after it. However, after the first two transactions I get:
Failed to submit transaction createInquiry: Error: Peer localhost:8051 has rejected transaction "e8a83c12bfbcae97c7a3f2baaad7735fe8b44195a0ce252a3533a7b4a2a8103b" with code "ENDORSEMENT_POLICY_FAILURE"
can you stop, remove and kill containers and try once again to instantiate.
In the hyperledger fabric documentation, there are 2 terms used
1. Install the chaincode on peers and
2. Instantiate the chaincode on the channel
What are the major differences between these two?
In the documentation it said that a chaincode can be installed on multiple peers but can be instantiated once. I understood this point as a channel only needs the information about the channel.
I was following the balance-transfer example, so after channel creation, peers need to be joined to that channel.
There are 2 peers which joined the channel ["peer0.org1.example.com", "peer0.org1.example.com"], so when I am instantiating the chaincode it is creating 2 docker images of chaincode
dev-peer0.org1.example.com-chaincode-v0
dev-peer1.org1.example.com-chaincode-v0
What these 2 images really mean?
Isn't initializing the chaincode means for the channel?
Or channel initialize it on all the peers who joined it?
Where actually this initialization is happening?
Thanks!
Thanks to #PaulO'Mahony and #kajuken for the resources and explanation.
Following are the summary of my doubts:
A chaincode runs in a Docker container that is associated with any peer that needs to interact with it.
Chaincode is installed on a peer, then instantiated on a channel.
All members that want to submit transactions or read data by using a chaincode need to install the chaincode on their peer.
Instantiation will input the initial data used by the chaincode, and then start the chaincode containers on peers joined to the channel with the chaincode installed.
Note that only one network member needs to instantiate a chaincode. If a peer with a chaincode installed joins a channel where it has already been instantiated, the chaincode container will start automatically.
a chaincode is installed onto the file system of every peer that joins a channel, the chaincode must then be instantiated on the channel so that peers can interact with the ledger via the chaincode container. The instantiation performs any necessary initialization of the chaincode. This will often involve setting the key value pairs that comprise a chaincode's initial world state.
A peer can the install the chaincode once, and then use the same chaincode container on any channel where it has been instantiated.
References:
install and instantiate the chaincode
instantiate the chaincode
What these 2 images really mean?
Isn't initializing the chaincode means for the channel?
Yes and no. Every peer needs the same version of the chaincode installed on itself since everybody needs to be able to execute and verify incoming queries/invokes.
So there are 2 steps to do.
install the chaincode on every peer on the channel
instantiate the chaincode on the channel
Where actually this initialization is happening?
So the instantiating of chaincode is happening last after every peer has "knowledge" of the chaincode and it can be verified.
Scenario:
I am creating hyperledger infrastructure with two organizations each having two peers and one orderer joining two channel.
Questions:
How are we define channels at the time of chain-code installation?
How the chain-code version maintains internally?
Thanks,
Murugesan
1) You can install chaincode on the peer(s) prior to creating / joining any channels. You then instantiate chaincode on specific channels. Those channels must have been created on the ordering service(s) and the peer(s) must join those channels. Once that has been done, you can then instantiate (active) chaincode on the channels you like. If a peer did not have the chaincode installed at the time it was instantiated on a channel, that's ok as well ... once the chaincode has been installed, it will be launched the first time you try to invoke the chaincode on that peer.
2) When you install chaincode, you specify a version. The same holds true for instantiating chaincode as well.