Channel Configuration (configtxgen)¶
This document describe the usage for the configtxgen
utility for
manipulating Hyperledger Fabric channel configuration.
For now, the tool is primarily focused on generating the genesis block for bootstrapping the orderer, but it is intended to be enhanced in the future for generating new channel configurations as well as reconfiguring existing channels.
Configuration Profiles¶
The configuration parameters supplied to the configtxgen
tool are
primarily provided by the configtx.yaml
file. This file is located
at fabric/sampleconfig/configtx.yaml
in the fabric.git
repository.
This configuration file is split primarily into three pieces.
- The
Profiles
section. By default, this section includes some sample configurations which can be used for development or testing scenarios, and refer to crypto material present in the fabric.git tree. These profiles can make a good starting point for construction a real deployment profile. Theconfigtxgen
tool allows you to specify the profile it is operating under by passing the-profile
flag. Profiles may explicitly declare all configuration, but usually inherit configuration from the defaults in (3) below. - The
Organizations
section. By default, this section includes a single reference to the sampleconfig MSP definition. For production deployments, the sample organization should be removed, and the MSP definitions of the network members should be referenced and defined instead. Each element in theOrganizations
section should be tagged with an anchor label such as&orgName
which will allow the definition to be referenced in theProfiles
sections. - The default sections. There are default sections for
Orderer
andApplication
configuration, these include attributes likeBatchTimeout
and are generally used as the base inherited values for the profiles.
This configuration file may be edited, or, individual properties may be
overridden by setting environment variables, such as
CONFIGTX_ORDERER_ORDERERTYPE=kafka
. Note that the Profiles
element and profile name do not need to be specified.
Bootstrapping the orderer¶
After creating a configuration profile as desired, simply invoke
configtxgen -profile <profile_name> -outputBlock orderer_genesisblock.pb
This will produce an orderer_genesisblock.pb
file in the current directory.
This genesis block is used to bootstrap the ordering system channel, which the
orderers use to authorize and orchestrate creation of other channels. By
default, the channel ID encoded into the genesis block by configtxgen
will be
testchainid
. It is recommended that you modify this identifier to something
which will be globally unique.
Then, to utilize this genesis block, before starting the orderer, simply
specify ORDERER_GENERAL_GENESISMETHOD=file
and
ORDERER_GENERAL_GENESISFILE=$PWD/orderer_genesisblock.pb
or modify the
orderer.yaml
file to encode these values.
Creating a channel¶
The tool can also output a channel creation tx by executing
configtxgen -profile <profile_name> -channelID <channel_name> -outputCreateChannelTx <tx_filename>
This will output a marshaled Envelope
message which may be sent to
broadcast to create a channel.
Reviewing a configuration¶
In addition to creating configuration, the configtxgen
tool is also
capable of inspecting configuration.
It supports inspecting both configuration blocks, and configuration
transactions. You may use the inspect flags -inspectBlock
and
-inspectChannelCreateTx
respectively with the path to a file to
inspect to output a human readable (JSON) representation of the
configuration.
You may even wish to combine the inspection with generation. For example:
$ build/bin/configtxgen -channelID foo -outputBlock foo_genesisblock.pb -inspectBlock foo_genesisblock.pb
2017-11-02 17:56:04.489 EDT [common/tools/configtxgen] main -> INFO 001 Loading configuration
2017-11-02 17:56:04.564 EDT [common/tools/configtxgen] doOutputBlock -> INFO 002 Generating genesis block
2017-11-02 17:56:04.564 EDT [common/tools/configtxgen] doOutputBlock -> INFO 003 Writing genesis block
2017-11-02 17:56:04.564 EDT [common/tools/configtxgen] doInspectBlock -> INFO 004 Inspecting block
2017-11-02 17:56:04.564 EDT [common/tools/configtxgen] doInspectBlock -> INFO 005 Parsing genesis block
{
"data": {
"data": [
{
"payload": {
"data": {
"config": {
"channel_group": {
"groups": {
"Consortiums": {
"groups": {
"SampleConsortium": {
"mod_policy": "/Channel/Orderer/Admins",
"values": {
"ChannelCreationPolicy": {
"mod_policy": "/Channel/Orderer/Admins",
"value": {
"type": 3,
"value": {
"rule": "ANY",
"sub_policy": "Admins"
}
},
"version": "0"
}
},
"version": "0"
}
},
"mod_policy": "/Channel/Orderer/Admins",
"policies": {
"Admins": {
"mod_policy": "/Channel/Orderer/Admins",
"policy": {
"type": 1,
"value": {
"rule": {
"n_out_of": {
"n": 0
}
},
"version": 0
}
},
"version": "0"
}
},
"version": "0"
},
"Orderer": {
"mod_policy": "Admins",
"policies": {
"Admins": {
"mod_policy": "Admins",
"policy": {
"type": 3,
"value": {
"rule": "MAJORITY",
"sub_policy": "Admins"
}
},
"version": "0"
},
"BlockValidation": {
"mod_policy": "Admins",
"policy": {
"type": 3,
"value": {
"rule": "ANY",
"sub_policy": "Writers"
}
},
"version": "0"
},
"Readers": {
"mod_policy": "Admins",
"policy": {
"type": 3,
"value": {
"rule": "ANY",
"sub_policy": "Readers"
}
},
"version": "0"
},
"Writers": {
"mod_policy": "Admins",
"policy": {
"type": 3,
"value": {
"rule": "ANY",
"sub_policy": "Writers"
}
},
"version": "0"
}
},
"values": {
"BatchSize": {
"mod_policy": "Admins",
"value": {
"absolute_max_bytes": 10485760,
"max_message_count": 10,
"preferred_max_bytes": 524288
},
"version": "0"
},
"BatchTimeout": {
"mod_policy": "Admins",
"value": {
"timeout": "2s"
},
"version": "0"
},
"ChannelRestrictions": {
"mod_policy": "Admins",
"version": "0"
},
"ConsensusType": {
"mod_policy": "Admins",
"value": {
"type": "solo"
},
"version": "0"
}
},
"version": "0"
}
},
"mod_policy": "Admins",
"policies": {
"Admins": {
"mod_policy": "Admins",
"policy": {
"type": 3,
"value": {
"rule": "MAJORITY",
"sub_policy": "Admins"
}
},
"version": "0"
},
"Readers": {
"mod_policy": "Admins",
"policy": {
"type": 3,
"value": {
"rule": "ANY",
"sub_policy": "Readers"
}
},
"version": "0"
},
"Writers": {
"mod_policy": "Admins",
"policy": {
"type": 3,
"value": {
"rule": "ANY",
"sub_policy": "Writers"
}
},
"version": "0"
}
},
"values": {
"BlockDataHashingStructure": {
"mod_policy": "Admins",
"value": {
"width": 4294967295
},
"version": "0"
},
"HashingAlgorithm": {
"mod_policy": "Admins",
"value": {
"name": "SHA256"
},
"version": "0"
},
"OrdererAddresses": {
"mod_policy": "/Channel/Orderer/Admins",
"value": {
"addresses": [
"127.0.0.1:7050"
]
},
"version": "0"
}
},
"version": "0"
},
"sequence": "0",
"type": 0
}
},
"header": {
"channel_header": {
"channel_id": "foo",
"epoch": "0",
"timestamp": "2017-11-02T21:56:04.000Z",
"tx_id": "6acfe1257c23a4f844cc299cbf53acc7bf8fa8bcf8aae8d049193098fe982eab",
"type": 1,
"version": 1
},
"signature_header": {
"nonce": "eZOKru6jmeiWykBtSDwnkGjyQt69GwuS"
}
}
}
}
]
},
"header": {
"data_hash": "/86I/7NScbH/bHcDcYG0/9qTmVPWVoVVfSN8NKMARKI=",
"number": "0"
},
"metadata": {
"metadata": [
"",
"",
"",
""
]
}
}