一、简介
“A highly-available key value store for shared configuration and service discovery.” Etcd是coreos开发的分布式服务系统，内部采用raft协议作为一致性算法。作为一个高可用的配置共享、服务发现的键值存储系统，Etcd有以下的特点： 1）简单：安装配置简单，而且提供了 HTTP API 进行交互，使用也很简单 2）安全：支持 SSL 证书验证 3）快速：根据官方提供的数据，单实例支持每秒2k+读操作、1k写操作 4）可靠：采用raft算法，实现分布式系统数据的可用性和一致性 Etcd构建自身高可用集群主要有三种形式: 1）静态发现: 预先已知 Etcd 集群中有哪些节点，在启动时直接指定好Etcd的各个node节点地址 2）Etcd动态发现: 通过已有的Etcd集群作为数据交互点，然后在扩展新的集群时实现通过已有集群进行服务发现的机制 3）DNS动态发现: 通过DNS查询方式获取其他节点地址信息 本文主要介绍第一种方式，后续会陆续介绍剩下的两种方式。(直接docker安装请移步：quay.io/coreos/etcd 基于Docker镜像的集群搭建)
二、环境介绍
三台虚拟机，系统环境均为Centos7，对应节点名称及IP地址如下(需要写入/etc/hosts)：
10.60.50.61 etcd-n1 10.60.50.62 etcd-n2 10.60.50.64 etcd-m
三、安装、配置Etcd
yum install etcd -y
yum安装的etcd默认配置文件在/etc/etcd/etcd.conf，以下将三个节点上的配置贴出来，请注意不同点（未贴出的，则表明不需要更改）
etcd-n1：
#[Member] #ETCD_CORS="" ETCD_DATA_DIR="/var/lib/etcd/default.etcd" #ETCD_WAL_DIR="" ETCD_LISTEN_PEER_URLS="http://0.0.0.0:2380" ETCD_LISTEN_CLIENT_URLS="http://0.0.0.0:2379,http://0.0.0.0:4001" #ETCD_MAX_SNAPSHOTS="5" #ETCD_MAX_WALS="5" ETCD_NAME="etcd-n1" #ETCD_SNAPSHOT_COUNT="100000" #ETCD_HEARTBEAT_INTERVAL="100" #ETCD_ELECTION_TIMEOUT="1000" #ETCD_QUOTA_BACKEND_BYTES="0" #ETCD_MAX_REQUEST_BYTES="1572864" #ETCD_GRPC_KEEPALIVE_MIN_TIME="5s" #ETCD_GRPC_KEEPALIVE_INTERVAL="2h0m0s" #ETCD_GRPC_KEEPALIVE_TIMEOUT="20s" # #[Clustering] ETCD_INITIAL_ADVERTISE_PEER_URLS="http://etcd-n1:2380" ETCD_ADVERTISE_CLIENT_URLS="http://etcd-n1:2379,http://etcd-n1:4001" #ETCD_DISCOVERY="" #ETCD_DISCOVERY_FALLBACK="proxy" #ETCD_DISCOVERY_PROXY="" #ETCD_DISCOVERY_SRV="" ETCD_INITIAL_CLUSTER="etcd-n1=http://etcd-n1:2380,etcd-n2=http://etcd-n2:2380,etcd-m=http://etcd-m:2380" ETCD_INITIAL_CLUSTER_TOKEN="mritd-etcd-cluster" ETCD_INITIAL_CLUSTER_STATE="new" #ETCD_STRICT_RECONFIG_CHECK="true" #ETCD_ENABLE_V2="true" # #[Proxy] #ETCD_PROXY="off" #ETCD_PROXY_FAILURE_WAIT="5000" #ETCD_PROXY_REFRESH_INTERVAL="30000" #ETCD_PROXY_DIAL_TIMEOUT="1000" #ETCD_PROXY_WRITE_TIMEOUT="5000" #ETCD_PROXY_READ_TIMEOUT="0" # #[Security] #ETCD_CERT_FILE="" #ETCD_KEY_FILE="" #ETCD_CLIENT_CERT_AUTH="false" #ETCD_TRUSTED_CA_FILE="" #ETCD_AUTO_TLS="false" #ETCD_PEER_CERT_FILE="" #ETCD_PEER_KEY_FILE="" #ETCD_PEER_CLIENT_CERT_AUTH="false" #ETCD_PEER_TRUSTED_CA_FILE="" #ETCD_PEER_AUTO_TLS="false" # #[Logging] #ETCD_DEBUG="false" #ETCD_LOG_PACKAGE_LEVELS="" #ETCD_LOG_OUTPUT="default" # #[Unsafe] #ETCD_FORCE_NEW_CLUSTER="false" # #[Version] #ETCD_VERSION="false" #ETCD_AUTO_COMPACTION_RETENTION="0" # #[Profiling] #ETCD_ENABLE_PPROF="false" #ETCD_METRICS="basic" # #[Auth] #ETCD_AUTH_TOKEN="simple"
etcd-n2
#[Member] #ETCD_CORS="" ETCD_DATA_DIR="/var/lib/etcd/default.etcd" #ETCD_WAL_DIR="" ETCD_LISTEN_PEER_URLS="http://0.0.0.0:2380" ETCD_LISTEN_CLIENT_URLS="http://0.0.0.0:2379,http://0.0.0.0:4001" #ETCD_MAX_SNAPSHOTS="5" #ETCD_MAX_WALS="5" ETCD_NAME="etcd-n2" #ETCD_SNAPSHOT_COUNT="100000" #ETCD_HEARTBEAT_INTERVAL="100" #ETCD_ELECTION_TIMEOUT="1000" #ETCD_QUOTA_BACKEND_BYTES="0" #ETCD_MAX_REQUEST_BYTES="1572864" #ETCD_GRPC_KEEPALIVE_MIN_TIME="5s" #ETCD_GRPC_KEEPALIVE_INTERVAL="2h0m0s" #ETCD_GRPC_KEEPALIVE_TIMEOUT="20s" # #[Clustering] ETCD_INITIAL_ADVERTISE_PEER_URLS="http://etcd-n2:2380" ETCD_ADVERTISE_CLIENT_URLS="http://etcd-n2:2379,http://etcd-n2:4001" #ETCD_DISCOVERY="" #ETCD_DISCOVERY_FALLBACK="proxy" #ETCD_DISCOVERY_PROXY="" #ETCD_DISCOVERY_SRV="" ETCD_INITIAL_CLUSTER="etcd-n1=http://etcd-n1:2380,etcd-n2=http://etcd-n2:2380,etcd-m=http://etcd-m:2380" ETCD_INITIAL_CLUSTER_TOKEN="mritd-etcd-cluster" ETCD_INITIAL_CLUSTER_STATE="new" #ETCD_STRICT_RECONFIG_CHECK="true" #ETCD_ENABLE_V2="true" # #[Proxy] #ETCD_PROXY="off" #ETCD_PROXY_FAILURE_WAIT="5000" #ETCD_PROXY_REFRESH_INTERVAL="30000" #ETCD_PROXY_DIAL_TIMEOUT="1000" #ETCD_PROXY_WRITE_TIMEOUT="5000" #ETCD_PROXY_READ_TIMEOUT="0" # #[Security] #ETCD_CERT_FILE="" #ETCD_KEY_FILE="" #ETCD_CLIENT_CERT_AUTH="false" #ETCD_TRUSTED_CA_FILE="" #ETCD_AUTO_TLS="false" #ETCD_PEER_CERT_FILE="" #ETCD_PEER_KEY_FILE="" #ETCD_PEER_CLIENT_CERT_AUTH="false" #ETCD_PEER_TRUSTED_CA_FILE="" #ETCD_PEER_AUTO_TLS="false" # #[Logging] #ETCD_DEBUG="false" #ETCD_LOG_PACKAGE_LEVELS="" #ETCD_LOG_OUTPUT="default" # #[Unsafe] #ETCD_FORCE_NEW_CLUSTER="false" # #[Version] #ETCD_VERSION="false" #ETCD_AUTO_COMPACTION_RETENTION="0" # #[Profiling] #ETCD_ENABLE_PPROF="false" #ETCD_METRICS="basic" # #[Auth] #ETCD_AUTH_TOKEN="simple"
etcd-m
#[Member] #ETCD_CORS="" ETCD_DATA_DIR="/var/lib/etcd/default.etcd" #ETCD_WAL_DIR="" ETCD_LISTEN_PEER_URLS="http://0.0.0.0:2380" ETCD_LISTEN_CLIENT_URLS="http://0.0.0.0:2379,http://0.0.0.0:4001" #ETCD_MAX_SNAPSHOTS="5" #ETCD_MAX_WALS="5" ETCD_NAME="etcd-m" #ETCD_SNAPSHOT_COUNT="100000" #ETCD_HEARTBEAT_INTERVAL="100" #ETCD_ELECTION_TIMEOUT="1000" #ETCD_QUOTA_BACKEND_BYTES="0" #ETCD_MAX_REQUEST_BYTES="1572864" #ETCD_GRPC_KEEPALIVE_MIN_TIME="5s" #ETCD_GRPC_KEEPALIVE_INTERVAL="2h0m0s" #ETCD_GRPC_KEEPALIVE_TIMEOUT="20s" # #[Clustering] ETCD_INITIAL_ADVERTISE_PEER_URLS="http://etcd-m:2380" ETCD_ADVERTISE_CLIENT_URLS="http://etcd-m:2379,http://etcd-m:4001" #ETCD_DISCOVERY="" #ETCD_DISCOVERY_FALLBACK="proxy" #ETCD_DISCOVERY_PROXY="" #ETCD_DISCOVERY_SRV="" ETCD_INITIAL_CLUSTER="etcd-n1=http://etcd-n1:2380,etcd-n2=http://etcd-n2:2380,etcd-m=http://etcd-m:2380" ETCD_INITIAL_CLUSTER_TOKEN="mritd-etcd-cluster" ETCD_INITIAL_CLUSTER_STATE="new" #ETCD_STRICT_RECONFIG_CHECK="true" #ETCD_ENABLE_V2="true" # #[Proxy] #ETCD_PROXY="off" #ETCD_PROXY_FAILURE_WAIT="5000" #ETCD_PROXY_REFRESH_INTERVAL="30000" #ETCD_PROXY_DIAL_TIMEOUT="1000" #ETCD_PROXY_WRITE_TIMEOUT="5000" #ETCD_PROXY_READ_TIMEOUT="0" # #[Security] #ETCD_CERT_FILE="" #ETCD_KEY_FILE="" #ETCD_CLIENT_CERT_AUTH="false" #ETCD_TRUSTED_CA_FILE="" #ETCD_AUTO_TLS="false" #ETCD_PEER_CERT_FILE="" #ETCD_PEER_KEY_FILE="" #ETCD_PEER_CLIENT_CERT_AUTH="false" #ETCD_PEER_TRUSTED_CA_FILE="" #ETCD_PEER_AUTO_TLS="false" # #[Logging] #ETCD_DEBUG="false" #ETCD_LOG_PACKAGE_LEVELS="" #ETCD_LOG_OUTPUT="default" # #[Unsafe] #ETCD_FORCE_NEW_CLUSTER="false" # #[Version] #ETCD_VERSION="false" #ETCD_AUTO_COMPACTION_RETENTION="0" # #[Profiling] #ETCD_ENABLE_PPROF="false" #ETCD_METRICS="basic" # #[Auth] #ETCD_AUTH_TOKEN="simple"
改好配置之后，在各个节点上开启etcd服务：
systemctl restart etcd
四、测试验证
[root@k8s-master ~]# etcdctl set testdir/testkey0 0 0 [root@k8s-master ~]# etcdctl set testdir/testkey1 1 1 [root@k8s-master ~]# etcdctl ls /testdir [root@k8s-master ~]# etcdctl ls testdir /testdir/testkey0 /testdir/testkey1 [root@k8s-master ~]# etcdctl get testdir/testkey1 1 [root@k8s-master ~]# etcdctl member list 4ba39103ae2e94df: name=etcd-n2 peerURLs=http://etcd-n2:2380 clientURLs=http://etcd-n2:2379,http://etcd-n2:4001 isLeader=false 94ae81297211716a: name=etcd-n1 peerURLs=http://etcd-n1:2380 clientURLs=http://etcd-n1:2379,http://etcd-n1:4001 isLeader=false f8f3c962865af414: name=etcd-m peerURLs=http://etcd-m:2380 clientURLs=http://etcd-m:2379,http://etcd-m:4001 isLeader=true
参考http://www.cnblogs.com/zhenyuyaodidiao/p/6237019.html