Updating a Channel Configuration

What is a Channel Configuration?

Channel configurations contain all of the information relevant to the administration of a channel. Most importantly, the channel configuration specifies which organizations are members of channel, but it also includes other channel-wide configuration information such as channel access policies and block batch sizes.

This configuration is stored on the ledger in a block, and is therefore known as a configuration (config) block. Configuration blocks contain a single configuration. The first of these blocks is known as the “genesis block” and contains the initial configuration required to bootstrap a channel. Each time the configuration of a channel changes it is done through a new configuration block, with the latest configuration block representing the current channel configuration. Orderers and peers keep the current channel configuration in memory to facilitate all channel operations such as cutting a new block and validating block transactions.

Because configurations are stored in blocks, updating a config happens through a process called a “configuration transaction” (even though the process is a little different from a normal transaction). Updating a config is a process of pulling the config, translating into a format that humans can read, modifying it and then submitting it for approval.

For a more in-depth look at the process for pulling a config and translating it into JSON, check out Adding an Org to a Channel. In this doc, we’ll be focusing on the different ways you can edit a config and the process for getting it signed.

Editing a Config

Channels are highly configurable, but not infinitely so. Different configuration elements have different modification policies (which specify the group of identities required to sign the config update).

To see the scope of what’s possible to change it’s important to look at a config in JSON format. The Adding an Org to a Channel tutorial generates one, so if you’ve gone through that doc you can simply refer to it. For those who have not, we’ll provide one here (for ease of readability, it might be helpful to put this config into a viewer that supports JSON folding, like atom or Visual Studio).

Click here to see the config

{
"channel_group": {
  "groups": {
    "Application": {
      "groups": {
        "Org1MSP": {
          "mod_policy": "Admins",
          "policies": {
            "Admins": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "Org1MSP",
                        "role": "ADMIN"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            },
            "Readers": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "Org1MSP",
                        "role": "MEMBER"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            },
            "Writers": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "Org1MSP",
                        "role": "MEMBER"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            }
          },
          "values": {
            "AnchorPeers": {
              "mod_policy": "Admins",
              "value": {
                "anchor_peers": [
                  {
                    "host": "peer0.org1.example.com",
                    "port": 7051
                  }
                ]
              },
              "version": "0"
            },
            "MSP": {
              "mod_policy": "Admins",
              "value": {
                "config": {
                  "admins": [
                    "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"
                  ],
                  "crypto_config": {
                    "identity_identifier_hash_function": "SHA256",
                    "signature_hash_family": "SHA2"
                  },
                  "name": "Org1MSP",
                  "root_certs": [
                    "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"
                  ],
                  "tls_root_certs": [
                    "LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSUNTVENDQWZDZ0F3SUJBZ0lSQUtsNEFQWmV6dWt0Nk8wYjRyYjY5Y0F3Q2dZSUtvWkl6ajBFQXdJd2RqRUwKTUFrR0ExVUVCaE1DVlZNeEV6QVJCZ05WQkFnVENrTmhiR2xtYjNKdWFXRXhGakFVQmdOVkJBY1REVk5oYmlCRwpjbUZ1WTJselkyOHhHVEFYQmdOVkJBb1RFRzl5WnpFdVpYaGhiWEJzWlM1amIyMHhIekFkQmdOVkJBTVRGblJzCmMyTmhMbTl5WnpFdVpYaGhiWEJzWlM1amIyMHdIaGNOTVRjeE1USTVNVGt5TkRBMldoY05NamN4TVRJM01Ua3kKTkRBMldqQjJNUXN3Q1FZRFZRUUdFd0pWVXpFVE1CRUdBMVVFQ0JNS1EyRnNhV1p2Y201cFlURVdNQlFHQTFVRQpCeE1OVTJGdUlFWnlZVzVqYVhOamJ6RVpNQmNHQTFVRUNoTVFiM0puTVM1bGVHRnRjR3hsTG1OdmJURWZNQjBHCkExVUVBeE1XZEd4elkyRXViM0puTVM1bGVHRnRjR3hsTG1OdmJUQlpNQk1HQnlxR1NNNDlBZ0VHQ0NxR1NNNDkKQXdFSEEwSUFCSnNpQXVjYlcrM0lqQ2VaaXZPakRiUmFyVlRjTW9TRS9mSnQyU0thR1d5bWQ0am5xM25MWC9vVApCVmpZb21wUG1QbGZ4R0VSWHl0UTNvOVZBL2hwNHBlalh6QmRNQTRHQTFVZER3RUIvd1FFQXdJQnBqQVBCZ05WCkhTVUVDREFHQmdSVkhTVUFNQThHQTFVZEV3RUIvd1FGTUFNQkFmOHdLUVlEVlIwT0JDSUVJSnlqZnFoa0FvY3oKdkRpNnNGSGFZL1Bvd2tPWkxPMHZ0VGdFRnVDbUpFalZNQW9HQ0NxR1NNNDlCQU1DQTBjQU1FUUNJRjVOVVdCVgpmSjgrM0lxU3J1NlFFbjlIa0lsQ0xDMnlvWTlaNHBWMnpBeFNBaUE5NWQzeDhBRXZIcUFNZnIxcXBOWHZ1TW5BCmQzUXBFa1gyWkh3ODZlQlVQZz09Ci0tLS0tRU5EIENFUlRJRklDQVRFLS0tLS0K"
                  ]
                },
                "type": 0
              },
              "version": "0"
            }
          },
          "version": "1"
        },
        "Org2MSP": {
          "mod_policy": "Admins",
          "policies": {
            "Admins": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "Org2MSP",
                        "role": "ADMIN"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            },
            "Readers": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "Org2MSP",
                        "role": "MEMBER"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            },
            "Writers": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "Org2MSP",
                        "role": "MEMBER"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            }
          },
          "values": {
            "AnchorPeers": {
              "mod_policy": "Admins",
              "value": {
                "anchor_peers": [
                  {
                    "host": "peer0.org2.example.com",
                    "port": 9051
                  }
                ]
              },
              "version": "0"
            },
            "MSP": {
              "mod_policy": "Admins",
              "value": {
                "config": {
                  "admins": [
                    "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"
                  ],
                  "crypto_config": {
                    "identity_identifier_hash_function": "SHA256",
                    "signature_hash_family": "SHA2"
                  },
                  "name": "Org2MSP",
                  "root_certs": [
                    "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"
                  ],
                  "tls_root_certs": [
                    "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"
                  ]
                },
                "type": 0
              },
              "version": "0"
            }
          },
          "version": "1"
        },
        "Org3MSP": {
          "groups": {},
          "mod_policy": "Admins",
          "policies": {
            "Admins": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "Org3MSP",
                        "role": "ADMIN"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            },
            "Readers": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "Org3MSP",
                        "role": "MEMBER"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            },
            "Writers": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "Org3MSP",
                        "role": "MEMBER"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            }
          },
          "values": {
            "MSP": {
              "mod_policy": "Admins",
              "value": {
                "config": {
                  "admins": [
                    "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"
                  ],
                  "crypto_config": {
                    "identity_identifier_hash_function": "SHA256",
                    "signature_hash_family": "SHA2"
                  },
                  "name": "Org3MSP",
                  "root_certs": [
                    "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"
                  ],
                  "tls_root_certs": [
                    "LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSUNTVENDQWZDZ0F3SUJBZ0lSQU9xc2JQQzFOVHJzclEvUUNpalh6K0F3Q2dZSUtvWkl6ajBFQXdJd2RqRUwKTUFrR0ExVUVCaE1DVlZNeEV6QVJCZ05WQkFnVENrTmhiR2xtYjNKdWFXRXhGakFVQmdOVkJBY1REVk5oYmlCRwpjbUZ1WTJselkyOHhHVEFYQmdOVkJBb1RFRzl5WnpNdVpYaGhiWEJzWlM1amIyMHhIekFkQmdOVkJBTVRGblJzCmMyTmhMbTl5WnpNdVpYaGhiWEJzWlM1amIyMHdIaGNOTVRjeE1USTVNVGt6T0RNd1doY05NamN4TVRJM01Ua3oKT0RNd1dqQjJNUXN3Q1FZRFZRUUdFd0pWVXpFVE1CRUdBMVVFQ0JNS1EyRnNhV1p2Y201cFlURVdNQlFHQTFVRQpCeE1OVTJGdUlFWnlZVzVqYVhOamJ6RVpNQmNHQTFVRUNoTVFiM0puTXk1bGVHRnRjR3hsTG1OdmJURWZNQjBHCkExVUVBeE1XZEd4elkyRXViM0puTXk1bGVHRnRjR3hsTG1OdmJUQlpNQk1HQnlxR1NNNDlBZ0VHQ0NxR1NNNDkKQXdFSEEwSUFCSVJTTHdDejdyWENiY0VLMmhxSnhBVm9DaDhkejNqcnA5RHMyYW9TQjBVNTZkSUZhVmZoR2FsKwovdGp6YXlndXpFalFhNlJ1MmhQVnRGM2NvQnJ2Ulpxalh6QmRNQTRHQTFVZER3RUIvd1FFQXdJQnBqQVBCZ05WCkhTVUVDREFHQmdSVkhTVUFNQThHQTFVZEV3RUIvd1FGTUFNQkFmOHdLUVlEVlIwT0JDSUVJQ2FkVERGa0JPTGkKblcrN2xCbDExL3pPbXk4a1BlYXc0MVNZWEF6cVhnZEVNQW9HQ0NxR1NNNDlCQU1DQTBjQU1FUUNJQlgyMWR3UwpGaG5NdDhHWXUweEgrUGd5aXQreFdQUjBuTE1Jc1p2dVlRaktBaUFLUlE5N2VrLzRDTzZPWUtSakR0VFM4UFRmCm9nTmJ6dTBxcThjbVhseW5jZz09Ci0tLS0tRU5EIENFUlRJRklDQVRFLS0tLS0K"
                  ]
                },
                "type": 0
              },
              "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"
        }
      },
      "version": "1"
    },
    "Orderer": {
      "groups": {
        "OrdererOrg": {
          "mod_policy": "Admins",
          "policies": {
            "Admins": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "OrdererMSP",
                        "role": "ADMIN"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            },
            "Readers": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "OrdererMSP",
                        "role": "MEMBER"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            },
            "Writers": {
              "mod_policy": "Admins",
              "policy": {
                "type": 1,
                "value": {
                  "identities": [
                    {
                      "principal": {
                        "msp_identifier": "OrdererMSP",
                        "role": "MEMBER"
                      },
                      "principal_classification": "ROLE"
                    }
                  ],
                  "rule": {
                    "n_out_of": {
                      "n": 1,
                      "rules": [
                        {
                          "signed_by": 0
                        }
                      ]
                    }
                  },
                  "version": 0
                }
              },
              "version": "0"
            }
          },
          "values": {
            "MSP": {
              "mod_policy": "Admins",
              "value": {
                "config": {
                  "admins": [
                    "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"
                  ],
                  "crypto_config": {
                    "identity_identifier_hash_function": "SHA256",
                    "signature_hash_family": "SHA2"
                  },
                  "name": "OrdererMSP",
                  "root_certs": [
                    "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"
                  ],
                  "tls_root_certs": [
                    "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"
                  ]
                },
                "type": 0
              },
              "version": "0"
            }
          },
          "version": "0"
        }
      },
      "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": 103809024,
            "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": "",
  "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"
    },
    "Consortium": {
      "mod_policy": "Admins",
      "value": {
        "name": "SampleConsortium"
      },
      "version": "0"
    },
    "HashingAlgorithm": {
      "mod_policy": "Admins",
      "value": {
        "name": "SHA256"
      },
      "version": "0"
    },
    "OrdererAddresses": {
      "mod_policy": "/Channel/Orderer/Admins",
      "value": {
        "addresses": [
          "orderer.example.com:7050"
        ]
      },
      "version": "0"
    }
  },
  "version": "0"
},
"sequence": "3",
"type": 0
}

A config might look intimidating in this form, but once you study it you’ll see that it has a logical structure.

Beyond the definitions of the policies – defining who can do certain things at the channel level, and who has the permission to change who can change the config – channels also have other kinds of features that can be modified using a config update. Adding an Org to a Channel takes you through one of the most important – adding an org to a channel. Some other things that are possible to change with a config update include:

  • Batch Size. These parameters dictate the number and size of transactions in a block. No block will appear larger than absolute_max_bytes large or with more than max_message_count transactions inside the block. If it is possible to construct a block under preferred_max_bytes, then a block will be cut prematurely, and transactions larger than this size will appear in their own block.

    {
      "absolute_max_bytes": 102760448,
      "max_message_count": 10,
      "preferred_max_bytes": 524288
    }
    
  • Batch Timeout. The amount of time to wait after the first transaction arrives for additional transactions before cutting a block. Decreasing this value will improve latency, but decreasing it too much may decrease throughput by not allowing the block to fill to its maximum capacity.

    { "timeout": "2s" }
    
  • Channel Restrictions. The total number of channels the orderer is willing to allocate may be specified as max_count. This is primarily useful in pre-production environments with weak consortium ChannelCreation policies.

    {
     "max_count":1000
    }
    
  • Channel Creation Policy. Defines the policy value which will be set as the mod_policy for the Application group of new channels for the consortium it is defined in. The signature set attached to the channel creation request will be checked against the instantiation of this policy in the new channel to ensure that the channel creation is authorized. Note that this config value is only set in the orderer system channel.

    {
    "type": 3,
    "value": {
      "rule": "ANY",
      "sub_policy": "Admins"
      }
    }
    
  • Kafka brokers. When ConsensusType is set to kafka, the brokers list enumerates some subset (or preferably all) of the Kafka brokers for the orderer to initially connect to at startup. Note that it is not possible to change your consensus type after it has been established (during the bootstrapping of the genesis block).

    {
      "brokers": [
        "kafka0:9092",
        "kafka1:9092",
        "kafka2:9092",
        "kafka3:9092"
      ]
    }
    
  • Anchor Peers Definition. Defines the location of the anchor peers for each Org.

    {
      "host": "peer0.org2.example.com",
        "port": 9051
    }
    
  • Hashing Structure. The block data is an array of byte arrays. The hash of the block data is computed as a Merkle tree. This value specifies the width of that Merkle tree. For the time being, this value is fixed to 4294967295 which corresponds to a simple flat hash of the concatenation of the block data bytes.

    { "width": 4294967295 }
    
  • Hashing Algorithm. The algorithm used for computing the hash values encoded into the blocks of the blockchain. In particular, this affects the data hash, and the previous block hash fields of the block. Note, this field currently only has one valid value (SHA256) and should not be changed.

    { "name": "SHA256" }
    
  • Block Validation. This policy specifies the signature requirements for a block to be considered valid. By default, it requires a signature from some member of the ordering org.

    {
      "type": 3,
      "value": {
        "rule": "ANY",
        "sub_policy": "Writers"
      }
    }
    
  • Orderer Address. A list of addresses where clients may invoke the orderer Broadcast and Deliver functions. The peer randomly chooses among these addresses and fails over between them for retrieving blocks.

    {
      "addresses": [
        "orderer.example.com:7050"
      ]
    }
    

Just as we add an Org by adding their artifacts and MSP information, you can remove them by reversing the process.

Note that once the consensus type has been defined and the network has been bootstrapped, it is not possible to change it through a configuration update.

There is another important channel configuration (especially for v1.1) known as Capability Requirements. It has its own doc that can be found here.

Let’s say you want to edit the block batch size for the channel (because this is a single numeric field, it’s one of the easiest changes to make). First to make referencing the JSON path easy, we define it as an environment variable.

To establish this, take a look at your config, find what you’re looking for, and back track the path.

If you find batch size, for example, you’ll see that it’s a value of the Orderer. Orderer can be found under groups, which is under channel_group. The batch size value has a parameter under value of max_message_count.

Which would make the path this:

 export MAXBATCHSIZEPATH=".channel_group.groups.Orderer.values.BatchSize.value.max_message_count"

Next, display the value of that property:

jq "$MAXBATCHSIZEPATH" config.json

Which should return a value of 10 (in our sample network at least).

Now, let’s set the new batch size and display the new value:

 jq "$MAXBATCHSIZEPATH = 20" config.json > modified_config.json
 jq "$MAXBATCHSIZEPATH" modified_config.json

Once you’ve modified the JSON, it’s ready to be converted and submitted. The scripts and steps in Adding an Org to a Channel will take you through the process for converting the JSON, so let’s look at the process of submitting it.

Get the Necessary Signatures

Once you’ve successfully generated the protobuf file, it’s time to get it signed. To do this, you need to know the relevant policy for whatever it is you’re trying to change.

By default, editing the configuration of:

  • A particular org (for example, changing anchor peers) requires only the admin signature of that org.
  • The application (like who the member orgs are) requires a majority of the application organizations’ admins to sign.
  • The orderer requires a majority of the ordering organizations’ admins (of which there are by default only 1).
  • The top level channel group requires both the agreement of a majority of application organization admins and orderer organization admins.

If you have made changes to the default policies in the channel, you’ll need to compute your signature requirements accordingly.

Note: you may be able to script the signature collection, dependent on your application. In general, you may always collect more signatures than are required.

The actual process of getting these signatures will depend on how you’ve set up your system, but there are two main implementations. Currently, the Fabric command line defaults to a “pass it along” system. That is, the Admin of the Org proposing a config update sends the update to someone else (another Admin, typically) who needs to sign it. This Admin signs it (or doesn’t) and passes it along to the next Admin, and so on, until there are enough signatures for the config to be submitted.

This has the virtue of simplicity – when there are enough signatures, the last Admin can simply submit the config transaction (in Fabric, the peer channel update command includes a signature by default). However, this process will only be practical in smaller channels, since the “pass it along” method can be time consuming.

The other option is to submit the update to every Admin on a channel and wait for enough signatures to come back. These signatures can then be stitched together and submitted. This makes life a bit more difficult for the Admin who created the config update (forcing them to deal with a file per signer) but is the recommended workflow for users which are developing Fabric management applications.

Once the config has been added to the ledger, it will be a best practice to pull it and convert it to JSON to check to make sure everything was added correctly. This will also serve as a useful copy of the latest config.