Fabric 1.4.1引入Raft排序服务, 运维界比较出名的etcd实现的orderer服务。后生可畏, etcd是中国一个年轻人的作品, 实现了raft协议, 在k8s等容器化, 虚拟化, 集群化有官方应用。etcd也是go语言编写, fabric开窍了, 直接把etcd和orderer整合了, 相比kafka/zookeeper的排序服务，搭建简单多了，也比kafka这些省了很多资源(kafka默认开的堆是2GB..), 所以个人是强烈推荐使用，尽量出来不久，但在1.4LTS维护, 是有保障的。

快速看下1.4.1的fabric-samples/first-network里面的raft排序服务如果使用。 运行

./byfn.sh up -o etcdraft

创始块创建命令行是

configtxgen -profile SampleMultiNodeEtcdRaft -channelID byfn-sys-channel -outputBlock ./channel-artifacts/genesis.block

查看configtx.yaml对应内容

    SampleMultiNodeEtcdRaft:
        <<: *ChannelDefaults
        Capabilities:
            <<: *ChannelCapabilities
        Orderer:
            <<: *OrdererDefaults
            OrdererType: etcdraft
            EtcdRaft:
                Consenters:
                - Host: orderer.example.com
                  Port: 7050
                  ClientTLSCert: crypto-config/ordererOrganizations/example.com/orderers/orderer.example.com/tls/server.crt
                  ServerTLSCert: crypto-config/ordererOrganizations/example.com/orderers/orderer.example.com/tls/server.crt
                - Host: orderer2.example.com
                  Port: 7050
                  ClientTLSCert: crypto-config/ordererOrganizations/example.com/orderers/orderer2.example.com/tls/server.crt
                  ServerTLSCert: crypto-config/ordererOrganizations/example.com/orderers/orderer2.example.com/tls/server.crt
                - Host: orderer3.example.com
                  Port: 7050
                  ClientTLSCert: crypto-config/ordererOrganizations/example.com/orderers/orderer3.example.com/tls/server.crt
                  ServerTLSCert: crypto-config/ordererOrganizations/example.com/orderers/orderer3.example.com/tls/server.crt
                - Host: orderer4.example.com
                  Port: 7050
                  ClientTLSCert: crypto-config/ordererOrganizations/example.com/orderers/orderer4.example.com/tls/server.crt
                  ServerTLSCert: crypto-config/ordererOrganizations/example.com/orderers/orderer4.example.com/tls/server.crt
                - Host: orderer5.example.com
                  Port: 7050
                  ClientTLSCert: crypto-config/ordererOrganizations/example.com/orderers/orderer5.example.com/tls/server.crt
                  ServerTLSCert: crypto-config/ordererOrganizations/example.com/orderers/orderer5.example.com/tls/server.crt
            Addresses:
                - orderer.example.com:7050
                - orderer2.example.com:7050
                - orderer3.example.com:7050
                - orderer4.example.com:7050
                - orderer5.example.com:7050

            Organizations:
            - *OrdererOrg
            Capabilities:
                <<: *OrdererCapabilities
        Application:
            <<: *ApplicationDefaults
            Organizations:
            - <<: *OrdererOrg
        Consortiums:
            SampleConsortium:
                Organizations:
                - *Org1
                - *Org2

主要是指定了ClientTLSCert, ServerTLSCert 对应的docker-compse文件是docker-compose-etcdraft2.yaml, 基于orderer-base覆盖

  orderer-base:
    image: hyperledger/fabric-orderer:$IMAGE_TAG
    environment:
      - FABRIC_LOGGING_SPEC=INFO
      - ORDERER_GENERAL_LISTENADDRESS=0.0.0.0
      - ORDERER_GENERAL_GENESISMETHOD=file
      - ORDERER_GENERAL_GENESISFILE=/var/hyperledger/orderer/orderer.genesis.block
      - ORDERER_GENERAL_LOCALMSPID=OrdererMSP
      - ORDERER_GENERAL_LOCALMSPDIR=/var/hyperledger/orderer/msp
      # enabled TLS
      - ORDERER_GENERAL_TLS_ENABLED=true
      - ORDERER_GENERAL_TLS_PRIVATEKEY=/var/hyperledger/orderer/tls/server.key
      - ORDERER_GENERAL_TLS_CERTIFICATE=/var/hyperledger/orderer/tls/server.crt
      - ORDERER_GENERAL_TLS_ROOTCAS=[/var/hyperledger/orderer/tls/ca.crt]
      - ORDERER_KAFKA_TOPIC_REPLICATIONFACTOR=1
      - ORDERER_KAFKA_VERBOSE=true
      - ORDERER_GENERAL_CLUSTER_CLIENTCERTIFICATE=/var/hyperledger/orderer/tls/server.crt
      - ORDERER_GENERAL_CLUSTER_CLIENTPRIVATEKEY=/var/hyperledger/orderer/tls/server.key
      - ORDERER_GENERAL_CLUSTER_ROOTCAS=[/var/hyperledger/orderer/tls/ca.crt]
    working_dir: /opt/gopath/src/github.com/hyperledger/fabric
    command: orderer

额外的一些etcd配置参数看不到, 我们去启动的orderer容器的配置文件看下

docker exec -it -e LINES=$(tput lines) -e COLUMNS=$(tput cols) orderer.example.com  bash

查看配置文件/etc/hyperledger/fabric/configtx.yaml,涉及的配置内容, awesome, options里面有etcd的配置项, 我们应该是在生成创始块的时候才能覆盖。

    # EtcdRaft defines configuration which must be set when the "etcdraft"
    # orderertype is chosen.
    EtcdRaft:
        # The set of Raft replicas for this network. For the etcd/raft-based
        # implementation, we expect every replica to also be an OSN. Therefore,
        # a subset of the host:port items enumerated in this list should be
        # replicated under the Orderer.Addresses key above.
        Consenters:
            - Host: raft0.example.com
              Port: 7050
              ClientTLSCert: path/to/ClientTLSCert0
              ServerTLSCert: path/to/ServerTLSCert0
            - Host: raft1.example.com
              Port: 7050
              ClientTLSCert: path/to/ClientTLSCert1
              ServerTLSCert: path/to/ServerTLSCert1
            - Host: raft2.example.com
              Port: 7050
              ClientTLSCert: path/to/ClientTLSCert2
              ServerTLSCert: path/to/ServerTLSCert2

        # Options to be specified for all the etcd/raft nodes. The values here
        # are the defaults for all new channels and can be modified on a
        # per-channel basis via configuration updates.
        Options:
            # TickInterval is the time interval between two Node.Tick invocations.
            TickInterval: 500ms

            # ElectionTick is the number of Node.Tick invocations that must pass
            # between elections. That is, if a follower does not receive any
            # message from the leader of current term before ElectionTick has
            # elapsed, it will become candidate and start an election.
            # ElectionTick must be greater than HeartbeatTick.
            ElectionTick: 10

            # HeartbeatTick is the number of Node.Tick invocations that must
            # pass between heartbeats. That is, a leader sends heartbeat
            # messages to maintain its leadership every HeartbeatTick ticks.
            HeartbeatTick: 1

            # MaxInflightBlocks limits the max number of in-flight append messages
            # during optimistic replication phase.
            MaxInflightBlocks: 5

            # SnapshotIntervalSize defines number of bytes per which a snapshot is taken
            SnapshotIntervalSize: 20 MB

对应的orderer.yaml有一些配置，对etcd不熟, 需要研究下。

################################################################################
#
#   Consensus Configuration
#
#   - This section contains config options for a consensus plugin. It is opaque
#     to orderer, and completely up to consensus implementation to make use of.
#
################################################################################
Consensus:
    # The allowed key-value pairs here depend on consensus plugin. For etcd/raft,
    # we use following options:

    # WALDir specifies the location at which Write Ahead Logs for etcd/raft are
    # stored. Each channel will have its own subdir named after channel ID.
    WALDir: /var/hyperledger/production/orderer/etcdraft/wal

    # SnapDir specifies the location at which snapshots for etcd/raft are
    # stored. Each channel will have its own subdir named after channel ID.
    SnapDir: /var/hyperledger/production/orderer/etcdraft/snapshot

把东西做简单是不简单的事情 , 给raft排序服务点赞。

最近华为事件，笔者深感纯做应用太被动，陆续的后面的分享方向是如何造轮子，和深挖源码实现，互勉吧。