Centos7下Etcd集羣搭建

1、簡介

「A highly-available key value store for shared configuration and service discovery.」
　　Etcd是coreos開發的分佈式服務系統，內部採用raft協議做爲一致性算法。做爲一個高可用的配置共享、服務發現的鍵值存儲系統，Etcd有如下的特色：
　　　　1）簡單：安裝配置簡單，並且提供了 HTTP API 進行交互，使用也很簡單
　　　　2）安全：支持 SSL 證書驗證
　　　　3）快速：根據官方提供的數據，單實例支持每秒2k+讀操做、1k寫操做
　　　　4）可靠：採用raft算法，實現分佈式系統數據的可用性和一致性
　　Etcd構建自身高可用集羣主要有三種形式:
　　　　1）靜態發現: 預先已知 Etcd 集羣中有哪些節點，在啓動時直接指定好Etcd的各個node節點地址
　　　　2）Etcd動態發現: 經過已有的Etcd集羣做爲數據交互點，而後在擴展新的集羣時實現經過已有集羣進行服務發現的機制
　　　　3）DNS動態發現: 經過DNS查詢方式獲取其餘節點地址信息
　　本文主要介紹第一種方式，後續會陸續介紹剩下的兩種方式。(直接docker安裝請移步：quay.io/coreos/etcd 基於Docker鏡像的集羣搭建)

2、環境介紹

  三臺虛擬機，系統環境均爲Centos7，對應節點名稱及IP地址以下(須要寫入/etc/hosts)：

10.60.50.61  etcd-n1
10.60.50.62  etcd-n2
10.60.50.64  etcd-m

3、安裝、配置Etcd

yum install etcd -y

yum安裝的etcd默認配置文件在/etc/etcd/etcd.conf，如下將三個節點上的配置貼出來，請注意不一樣點（未貼出的，則代表不須要更改）

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"

改好配置以後，在各個節點上開啓etcd服務：

systemctl restart etcd

4、測試驗證

[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

參考http://www.cnblogs.com/zhenyuyaodidiao/p/6237019.html