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Update a Channel

This guide covers how to modify a Fabric channel configuration — adding organizations, updating policies, and modifying anchor peers.

Prerequisites​

  • A running Fabric network with at least one channel
  • Admin access to the organizations involved in the update
  • Understanding of Fabric channel policies

How Channel Updates Work​

Fabric channel configuration changes require a config update transaction:

  1. Fetch the current channel config
  2. Modify the config (add org, change policy, etc.)
  3. Compute the config update (diff between old and new)
  4. Collect required signatures (based on the channel's modification policy)
  5. Submit the signed update to the orderer

ChainLaunch automates steps 1-3 and provides a UI for steps 4-5.

Update via the UI​

Add an Organization to a Channel​

  1. Go to Networks and select your Fabric network
  2. Click the Channels tab and select the channel
  3. Click Update Channel
  4. Select Add Organization
  5. Choose the organization from the dropdown (it must already exist in ChainLaunch)
  6. Review the proposed config change
  7. Click Sign & Submit

ChainLaunch will collect signatures from the required organizations based on the channel's modification policy (typically MAJORITY of existing orgs).

Update Anchor Peers​

Anchor peers enable cross-org gossip communication. To update them:

  1. Open the channel configuration
  2. Click Update Channel > Anchor Peers
  3. For each organization, select which peer(s) should serve as anchor peers
  4. Sign and submit the update

Modify Policies​

  1. Open the channel configuration
  2. Click Update Channel > Policies
  3. Select the policy to modify (e.g., Readers, Writers, Admins)
  4. Edit the policy rule (e.g., change from MAJORITY to ANY)
  5. Sign and submit
warning

Changing policies can affect who can read, write, or administer the channel. Always review policy changes carefully with all consortium members before submitting.

Update via API​

Fetch Current Config​

curl -s http://localhost:8100/api/v1/networks/{networkId}/channels/{channelName}/config | jq

Submit a Config Update​

curl -X PUT http://localhost:8100/api/v1/networks/{networkId}/channels/{channelName}/config \
  -H "Content-Type: application/json" \
  -d '{
    "organizations": ["Org1MSP", "Org2MSP", "Org3MSP"],
    "policies": {
      "Readers": { "type": "ImplicitMeta", "rule": "ANY Readers" },
      "Writers": { "type": "ImplicitMeta", "rule": "ANY Writers" },
      "Admins": { "type": "ImplicitMeta", "rule": "MAJORITY Admins" }
    }
  }'

Update Anchor Peers via API​

curl -X PUT http://localhost:8100/api/v1/networks/{networkId}/channels/{channelName}/anchor-peers \
  -H "Content-Type: application/json" \
  -d '{
    "organizationId": "Org1MSP",
    "anchorPeers": [
      { "host": "peer0.org1.example.com", "port": 7051 }
    ]
  }'

Common Scenarios​

Adding a New Organization to an Existing Network​

  1. Create the organization in ChainLaunch
  2. Create nodes (peers) for the new org
  3. Update the channel to include the new org (this page)
  4. Have the new org's peers join the channel
  5. Update anchor peers for the new org

Changing the Endorsement Policy​

If you need to change which orgs must endorse transactions:

  1. Update the channel's chaincode endorsement policy
  2. This is done during chaincode deployment, not via channel config update

Video Walkthrough​

Next Steps​