How to configure multiple anchor peers

Question

I learned form this site that each member on a channel can have multiple anchor peers to prevent SPOF.

I would like to try multiple anchor peer in fabcar-demo.

Kindly let me know how to configure multiple anchor peers.

Answer 1

In order to have more than one anchor peer per organization you need to configure it with configtx.yaml, e.g. you should add new anchor peers into the following section:

Organizations:

    - &Org1
        # DefaultOrg defines the organization which is used in the sampleconfig
        # of the fabric.git development environment
        Name: Org1MSP

        # ID to load the MSP definition as
        ID: Org1MSP

        MSPDir: crypto-config/peerOrganizations/org1.example.com/msp

        AnchorPeers:
            # AnchorPeers defines the location of peers which can be used
            # for cross org gossip communication.  Note, this value is only
            # encoded in the genesis block in the Application section context
            - Host: peer0.org1.example.com
              Port: 7051
            - Host: peer1.org1.example.com
              Port: 7051


    - &Org2
        # DefaultOrg defines the organization which is used in the sampleconfig
        # of the fabric.git development environment
        Name: Org2MSP

        # ID to load the MSP definition as
        ID: Org2MSP

        MSPDir: crypto-config/peerOrganizations/org2.example.com/msp

        AnchorPeers:
            # AnchorPeers defines the location of peers which can be used
            # for cross org gossip communication.  Note, this value is only
            # encoded in the genesis block in the Application section context
            - Host: peer0.org2.example.com
              Port: 7051
            - Host: peer1.org2.example.com
              Port: 7051

This will define two anchor peers per each organization. Next you need to use configtxgen to produce config update transaction to include those anchors peers for both orgs:

configtxgen -profile TwoOrgsChannel -channelID mychannel -outputAnchorPeersUpdate=Org1MSPanchors.tx -asOrg=Org1MSP
configtxgen -profile TwoOrgsChannel -channelID mychannel -outputAnchorPeersUpdate=Org2MSPanchors.tx -asOrg=Org2MSP

To update channel run:

# updating anchors for Org1
CORE_PEER_ADDRESS=peer0.org.example.com peer channel update -f Org1MSPanchors.tx -c mychannel -o orderer.example.com:7050

against endorsing peer of each org respectively.