Centos7系统-postgresql+etcd+patroni+haproxy+keepalived高可用集群部署
一、概况
1、概念
pgsql高可用集群采用postgresql+etcd+patroni+haproxy+keepalived等软件实现，以postgresql做数据库，etcd存储集群状态，patroni与etcd结合实现数据库集群故障切换，
haproxy实现数据库高可用（读读写分离），keepalived实现VIP跳转。
2、拓扑图
软件下载地址：
链接：https://pan.baidu.com/s/1VIWwXcfQRCumJjEXndSXPQ
提取码：5bpz
二、postgresql部署（三个节点）
1、下载解压
https://www.enterprisedb.com/download-postgresql-binaries mkdir -p /data/pg_data tar xf postgresql-10.18-1-linux-x64-binaries.tar.gz -C /data/
2、创建用户并授权
useradd postgres passwd postgres chown -R postgres.postgres /data/
3、初始化数据库（postgres用户下）
切换目录 [root@centos7 ~]# su – postgres 初始化目录 [postgres@centos7 ~]$ /data/pgsql/bin/initdb -D /data/pg_data/
4、配置变量
su – postgres vim .bash_profile PATH=$PATH:$HOME/bin export PATH export PATH export PGHOME=/data/pgsql export PATH=$PATH:$PGHOME/bin export PGDATA=/data/pg_data export PGLOG=/data/pg_log/pg.log source .bash_profile mkdir -p /data/pg_log chown postgres.postgres /data/pg_data chown postgres.postgres /data/pg_log
5、配置postgresql启动脚本
vim /etc/systemd/system/postgresql.service [Unit] Description=PostgreSQL database server After=network.target [Service] Type=forking User=postgres Group=postgres ExecStart= /data/pgsql/bin/pg_ctl -D /data/pg_data/ start ExecReload= /data/pgsql/bin/pg_ctl -D /data/pg_data/ restart ExecStop= /data/pgsql/bin/pg_ctl -D /data/pg_data/ stop PrivateTmp=true [Install] WantedBy=multi-user.target
6、启动与关闭
systemctl daemon-reload 开启 systemctl start postgresql 关闭 systemctl stop postgresql 重启 systemctl restart postgresql
7、数据库添加密码
[postgres@pgsql-19 ~]$ psql -U postgres -h localhost postgres=# alter user postgres with password 'P@sswrd';
8、允许远程连接
vim /data/pg_data/pg_hba.conf host all all 0.0.0.0/0 md5
vim /data/pg_data/postgresql.conf listen_addresses = '*' password_encryption = on 重启数据库 systemctl restart postgresql
三、etcd部署（三个节点）
1、下载解压
tar xf etcd-v3.1.20-linux-amd64.tar.gz -C /usr/local/ ln -s /usr/local/etcd-v3.1.20-linux-amd64 /usr/local/etcd
2、文件配置
mkdir -p /usr/local/etcd/data/etcd vim /usr/local/etcd/conf.yml name: pgsql_1971 data-dir: /usr/local/etcd/data/etcd listen-client-urls: http://192.168.19.71:2379,http://127.0.0.1:2379 advertise-client-urls: http://192.168.19.71:2379,http://127.0.0.1:2379 listen-peer-urls: http://192.168.19.71:2380 initial-advertise-peer-urls: http://192.168.19.71:2380 initial-cluster: pgsql_1971=http://192.168.19.71:2380,pgsql_1972=http://192.168.19.72:2380,pgsql_1973=http://192.168.19.73:2380 initial-cluster-token: etcd-cluster-token initial-cluster-state: new mkdir -p /usr/local/etcd/data/etc vim /usr/local/etcd/conf.yml name: pgsql_1972 data-dir: /usr/local/etcd/data/etcd listen-client-urls: http://192.168.19.72:2379,http://127.0.0.1:2379 advertise-client-urls: http://192.168.19.72:2379,http://127.0.0.1:2379 listen-peer-urls: http://192.168.19.72:2380 initial-advertise-peer-urls: http://192.168.19.72:2380 initial-cluster: pgsql_1971=http://192.168.19.71:2380,pgsql_1972=http://192.168.19.72:2380,pgsql_1973=http://192.168.19.73:2380 initial-cluster-token: etcd-cluster-token initial-cluster-state: new mkdir -p /usr/local/etcd/data/etc vim /usr/local/etcd/conf.yml name: pgsql_1973 data-dir: /usr/local/etcd/data/etcd listen-client-urls: http://192.168.19.73:2379,http://127.0.0.1:2379 advertise-client-urls: http://192.168.19.73:2379,http://127.0.0.1:2379 listen-peer-urls: http://192.168.19.73:2380 initial-advertise-peer-urls: http://192.168.19.73:2380 initial-cluster: pgsql_1971=http://192.168.19.71:2380,pgsql_1972=http://192.168.19.72:2380,pgsql_1973=http://192.168.19.73:2380 initial-cluster-token: etcd-cluster-token initial-cluster-state: new
3、启动并加入到开机自启中
加入开机自启里边 nohup /usr/local/etcd/etcd --config-file=/usr/local/etcd/conf.yml &
4、集群检查
netstat -lntup|grep etcd /usr/local/etcd/etcdctl member list
四、patroni部署（三个节点）
1、更新postgresql.conf文件
postgresql.conf配置如下
max_connections = '500'
max_wal_senders = '10'
port = '5432'
listen_addresses = '*'
synchronous_commit = on
full_page_writes = on
wal_log_hints = on
synchronous_standby_names = '*'
max_replication_slots = 10
wal_level = replica
注：wal_log_hints = on，synchronous_standby_names = '*' 这两个参数会导致数据库执行呆滞，后来者欢迎留言看是怎么回事儿
2、更新pg_hba.conf文件
vim /data/pg_data/pg_hba.conf 清理最后配置的配置，新增以下 local all all peer host all all 127.0.0.1/32 md5 host all postgres 127.0.0.1/32 md5 host all all 192.168.19.0/24 md5 host all all ::1/128 md5 local replication replicator peer host replication replicator 127.0.0.1/32 md5 host replication replicator ::1/128 md5 host replication replicator 192.168.19.71/32 md5 host replication replicator 192.168.19.72/32 md5 host replication replicator 192.168.19.73/32 md5
以上配置完成后，重启数据库
3、在主节点上创建复制槽，很重要，patroni会用到
postgres=# create user replicator replication login encrypted password '1qaz2wsx';
4、配置stream replication（在两个从节点操作）
systemctl stop postgresql
su - postgres cd /data/ && rm -rf pg_data /data/pgsql/bin/pg_basebackup -h 192.168.19.71 -D /data/pg_data -U replicator -v -P -R
启动数据库
systemctl start postgresql
5、安装patroni（三个节点）
yum install -y python3 python-psycopg2 python3-devel pip3 install --upgrade pip pip3 install psycopg2-binary -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com pip3 install patroni[etcd] -i http://pypi.douban.com/simple/ --trusted-host pypi.douban.com 验证是否安装成功 which patroni patronictl --help
6、创建patroni配置文件
mkdir -p /usr/patroni/conf cd /usr/patroni/conf/
node1 scope: batman namespace: /service/ name: postgresql1 restapi: listen: 192.168.19.71:8008 connect_address: 192.168.19.71:8008 # certfile: /etc/ssl/certs/ssl-cert-snakeoil.pem # keyfile: /etc/ssl/private/ssl-cert-snakeoil.key # authentication: # username: username # password: password # ctl: # insecure: false # Allow connections to SSL sites without certs # certfile: /etc/ssl/certs/ssl-cert-snakeoil.pem # cacert: /etc/ssl/certs/ssl-cacert-snakeoil.pem etcd: #Provide host to do the initial discovery of the cluster topology: host: 192.168.19.71:2379 #Or use "hosts" to provide multiple endpoints #Could be a comma separated string: #hosts: host1:port1,host2:port2 #host: 192.168.19.71:2379,192.168.19.71:2379,192.168.19.73:2379 #or an actual yaml list: #hosts: #- host1:port1 #- host2:port2 #Once discovery is complete Patroni will use the list of advertised clientURLs #It is possible to change this behavior through by setting: #use_proxies: true #raft: # data_dir: . # self_addr: 192.168.19.71:2222 # partner_addrs: # - 192.168.19.71:2223 # - 192.168.19.71:2224 bootstrap: # this section will be written into Etcd:// /config after initializing new cluster # and all other cluster members will use it as a `global configuration` dcs: ttl: 30 loop_wait: 10 retry_timeout: 10 maximum_lag_on_failover: 1048576 # master_start_timeout: 300 # synchronous_mode: false #standby_cluster: #host: 192.168.19.71 #port: 1111 #primary_slot_name: patroni postgresql: use_pg_rewind: true # use_slots: true parameters: # wal_level: hot_standby # hot_standby: "on" # max_connections: 100 # max_worker_processes: 8 # wal_keep_segments: 8 # max_wal_senders: 10 # max_replication_slots: 10 # max_prepared_transactions: 0 # max_locks_per_transaction: 64 # wal_log_hints: "on" # track_commit_timestamp: "off" # archive_mode: "on" # archive_timeout: 1800s # archive_command: mkdir -p ../wal_archive && test ! -f ../wal_archive/%f && cp %p ../wal_archive/%f # recovery_conf: # restore_command: cp ../wal_archive/%f %p # some desired options for 'initdb' initdb: # Note: It needs to be a list (some options need values, others are switches) - encoding: UTF8 - data-checksums pg_hba: # Add following lines to pg_hba.conf after running 'initdb' # For kerberos gss based connectivity (discard @.*$) #- host replication replicator 192.168.19.71/32 gss include_realm=0 #- host all all 0.0.0.0/0 gss include_realm=0 - host replication replicator 192.168.19.71/32 md5 - host all all 0.0.0.0/0 md5 # - hostssl all all 0.0.0.0/0 md5 # Additional script to be launched after initial cluster creation (will be passed the connection URL as parameter) # post_init: /usr/local/bin/setup_cluster.sh # Some additional users users which needs to be created after initializing new cluster users: admin: password: admin options: - createrole - createdb postgresql: listen: 192.168.19.71:5432 connect_address: 192.168.19.71:5432 data_dir: /data/pg_data bin_dir: /data/pgsql/bin # config_dir: pgpass: /tmp/pgpass0 authentication: replication: username: replicator password: 1qaz2wsx superuser: username: postgres password: P@sswrd rewind: # Has no effect on postgres 10 and lower username: postgres password: P@sswrd # Server side kerberos spn # krbsrvname: postgres parameters: # Fully qualified kerberos ticket file for the running user # same as KRB5CCNAME used by the GSS # krb_server_keyfile: /var/spool/keytabs/postgres unix_socket_directories: '.' # Additional fencing script executed after acquiring the leader lock but before promoting the replica #pre_promote: /path/to/pre_promote.sh #watchdog: # mode: automatic # Allowed values: off, automatic, required # device: /dev/watchdog # safety_margin: 5 tags: nofailover: false noloadbalance: false clonefrom: false nosync: false ------------------------------------------------------------------------------ node2 scope: batman namespace: /service/ name: postgresql2 restapi: listen: 192.168.19.72:8008 connect_address: 192.168.19.72:8008 # certfile: /etc/ssl/certs/ssl-cert-snakeoil.pem # keyfile: /etc/ssl/private/ssl-cert-snakeoil.key # authentication: # username: username # password: password # ctl: # insecure: false # Allow connections to SSL sites without certs # certfile: /etc/ssl/certs/ssl-cert-snakeoil.pem # cacert: /etc/ssl/certs/ssl-cacert-snakeoil.pem etcd: #Provide host to do the initial discovery of the cluster topology: host: 192.168.19.72:2379 #Or use "hosts" to provide multiple endpoints #Could be a comma separated string: #hosts: host1:port1,host2:port2 #host: 192.168.19.71:2379,192.168.19.72:2379,192.168.19.73:2379 #or an actual yaml list: #hosts: #- host1:port1 #- host2:port2 #Once discovery is complete Patroni will use the list of advertised clientURLs #It is possible to change this behavior through by setting: #use_proxies: true #raft: # data_dir: . # self_addr: 192.168.19.72:2222 # partner_addrs: # - 192.168.19.72:2223 # - 192.168.19.72:2224 bootstrap: # this section will be written into Etcd:/ / /config after initializing new cluster # and all other cluster members will use it as a `global configuration` dcs: ttl: 30 loop_wait: 10 retry_timeout: 10 maximum_lag_on_failover: 1048576 # master_start_timeout: 300 # synchronous_mode: false #standby_cluster: #host: 192.168.19.72 #port: 1111 #primary_slot_name: patroni postgresql: use_pg_rewind: true # use_slots: true parameters: # wal_level: hot_standby # hot_standby: "on" # max_connections: 100 # max_worker_processes: 8 # wal_keep_segments: 8 # max_wal_senders: 10 # max_replication_slots: 10 # max_prepared_transactions: 0 # max_locks_per_transaction: 64 # wal_log_hints: "on" # track_commit_timestamp: "off" # archive_mode: "on" # archive_timeout: 1800s # archive_command: mkdir -p ../wal_archive && test ! -f ../wal_archive/%f && cp %p ../wal_archive/%f # recovery_conf: # restore_command: cp ../wal_archive/%f %p # some desired options for 'initdb' initdb: # Note: It needs to be a list (some options need values, others are switches) - encoding: UTF8 - data-checksums pg_hba: # Add following lines to pg_hba.conf after running 'initdb' # For kerberos gss based connectivity (discard @.*$) #- host replication replicator 192.168.19.72/32 gss include_realm=0 #- host all all 0.0.0.0/0 gss include_realm=0 - host replication replicator 192.168.19.72/32 md5 - host all all 0.0.0.0/0 md5 # - hostssl all all 0.0.0.0/0 md5 # Additional script to be launched after initial cluster creation (will be passed the connection URL as parameter) # post_init: /usr/local/bin/setup_cluster.sh # Some additional users users which needs to be created after initializing new cluster users: admin: password: admin options: - createrole - createdb postgresql: listen: 192.168.19.72:5432 connect_address: 192.168.19.72:5432 data_dir: /data/pg_data bin_dir: /data/pgsql/bin # config_dir: pgpass: /tmp/pgpass0 authentication: replication: username: replicator password: 1qaz2wsx superuser: username: postgres password: P@sswrd rewind: # Has no effect on postgres 10 and lower username: postgres password: P@sswrd # Server side kerberos spn # krbsrvname: postgres parameters: # Fully qualified kerberos ticket file for the running user # same as KRB5CCNAME used by the GSS # krb_server_keyfile: /var/spool/keytabs/postgres unix_socket_directories: '.' # Additional fencing script executed after acquiring the leader lock but before promoting the replica #pre_promote: /path/to/pre_promote.sh #watchdog: # mode: automatic # Allowed values: off, automatic, required # device: /dev/watchdog # safety_margin: 5 tags: nofailover: false noloadbalance: false clonefrom: false nosync: false ------------------------------------------------------------------------------ node3 scope: batman namespace: /service/ name: postgresql3 restapi: listen: 192.168.19.73:8008 connect_address: 192.168.19.73:8008 # certfile: /etc/ssl/certs/ssl-cert-snakeoil.pem # keyfile: /etc/ssl/private/ssl-cert-snakeoil.key # authentication: # username: username # password: password # ctl: # insecure: false # Allow connections to SSL sites without certs # certfile: /etc/ssl/certs/ssl-cert-snakeoil.pem # cacert: /etc/ssl/certs/ssl-cacert-snakeoil.pem etcd: #Provide host to do the initial discovery of the cluster topology: host: 192.168.19.73:2379 #Or use "hosts" to provide multiple endpoints #Could be a comma separated string: #hosts: host1:port1,host2:port2 #host: 192.168.19.73:2379,192.168.19.73:2379,192.168.19.73:2379 #or an actual yaml list: #hosts: #- host1:port1 #- host2:port2 #Once discovery is complete Patroni will use the list of advertised clientURLs #It is possible to change this behavior through by setting: #use_proxies: true #raft: # data_dir: . # self_addr: 192.168.19.73:2222 # partner_addrs: # - 192.168.19.73:2223 # - 192.168.19.73:2224 bootstrap: # this section will be written into Etcd:/ / /config after initializing new cluster # and all other cluster members will use it as a `global configuration` dcs: ttl: 30 loop_wait: 10 retry_timeout: 10 maximum_lag_on_failover: 1048576 # master_start_timeout: 300 # synchronous_mode: false #standby_cluster: #host: 192.168.19.73 #port: 1111 #primary_slot_name: patroni postgresql: use_pg_rewind: true # use_slots: true parameters: # wal_level: hot_standby # hot_standby: "on" # max_connections: 100 # max_worker_processes: 8 # wal_keep_segments: 8 # max_wal_senders: 10 # max_replication_slots: 10 # max_prepared_transactions: 0 # max_locks_per_transaction: 64 # wal_log_hints: "on" # track_commit_timestamp: "off" # archive_mode: "on" # archive_timeout: 1800s # archive_command: mkdir -p ../wal_archive && test ! -f ../wal_archive/%f && cp %p ../wal_archive/%f # recovery_conf: # restore_command: cp ../wal_archive/%f %p # some desired options for 'initdb' initdb: # Note: It needs to be a list (some options need values, others are switches) - encoding: UTF8 - data-checksums pg_hba: # Add following lines to pg_hba.conf after running 'initdb' # For kerberos gss based connectivity (discard @.*$) #- host replication replicator 192.168.19.73/32 gss include_realm=0 #- host all all 0.0.0.0/0 gss include_realm=0 - host replication replicator 192.168.19.73/32 md5 - host all all 0.0.0.0/0 md5 # - hostssl all all 0.0.0.0/0 md5 # Additional script to be launched after initial cluster creation (will be passed the connection URL as parameter) # post_init: /usr/local/bin/setup_cluster.sh # Some additional users users which needs to be created after initializing new cluster users: admin: password: admin options: - createrole - createdb postgresql: listen: 192.168.19.73:5432 connect_address: 192.168.19.73:5432 data_dir: /data/pg_data bin_dir: /data/pgsql/bin # config_dir: pgpass: /tmp/pgpass0 authentication: replication: username: replicator password: 1qaz2wsx superuser: username: postgres password: P@sswrd rewind: # Has no effect on postgres 10 and lower username: postgres password: P@sswrd # Server side kerberos spn # krbsrvname: postgres parameters: # Fully qualified kerberos ticket file for the running user # same as KRB5CCNAME used by the GSS # krb_server_keyfile: /var/spool/keytabs/postgres unix_socket_directories: '.' # Additional fencing script executed after acquiring the leader lock but before promoting the replica #pre_promote: /path/to/pre_promote.sh #watchdog: # mode: automatic # Allowed values: off, automatic, required # device: /dev/watchdog # safety_margin: 5 tags: nofailover: false noloadbalance: false clonefrom: false nosync: false
7、依次启动patroni服务
Postgres用户下启动 nohup patroni /usr/patroni/conf/patroni_postgresql.yml &
8、patroni配置启动脚本
为了方便开机自启，故配置成 patroni.service，3个node都需要进行配置，配置好patroni.service后就可以直接在root用户下切换Leader以及重启postgres节点等操作
[root@pgsql_1971 ~]$ vim /etc/systemd/system/patroni.service [Unit] Description=patroni - a high-availability PostgreSQL Documentation=https://patroni.readthedocs.io/en/latest/index.html After=syslog.target network.target etcd.target Wants=network-online.target [Service] Type=simple User=postgres Group=postgres PermissionsStartOnly=true ExecStart=/usr/local/bin/patroni /usr/patroni/conf/patroni_postgresql.yml ExecReload=/bin/kill -HUP $MAINPID LimitNOFILE=65536 KillMode=process KillSignal=SIGINT Restart=on-abnormal RestartSec=30s TimeoutSec=0 [Install] WantedBy=multi-user.target
9、禁用postgresql脚本采用patroni服务启动数据库
禁止 postgresql 的自启动，通过 patroni 来管理 postgresql systemctl stop postgresql systemctl status postgresql systemctl disable postgresql systemctl status patroni systemctl start patroni systemctl enable patroni
五、集群检查
1、数据库集群检查
patronictl -c /usr/patroni/conf/patroni_postgresql.yml list
2、etcd检查
root@pgsql_1971 ~]# /usr/local/etcd/etcdctl ls /service/batman
root@pgsql_1971 ~]# /usr/local/etcd/etcdctl get /service/batman/members/postgresql1
六、haproxy部署（两个从节点）
1、安装haproxy服务
yum install -y haproxy cp -r /etc/haproxy/haproxy.cfg /etc/haproxy/haproxy.cfg_bak
2、配置文件
vi /etc/haproxy/haproxy.cfg
#---------------------------------------------------------------------
# 全局定义
global
# log语法：log [max_level_1]
# 全局的日志配置，使用log关键字，指定使用127.0.0.1上的syslog服务中的local0日志设备，
# 记录日志等级为info的日志
# log 127.0.0.1 local0 info
log 127.0.0.1 local1 notice
chroot /var/lib/haproxy
pidfile /var/run/haproxy.pid
# 定义每个haproxy进程的最大连接数 ，由于每个连接包括一个客户端和一个服务器端，
# 所以单个进程的TCP会话最大数目将是该值的两倍。
maxconn 4096
# 用户，组
user haproxy
group haproxy
# 以守护进程的方式运行
daemon
# turn on stats unix socket
stats socket /var/lib/haproxy/stats
#---------------------------------------------------------------------
# 默认部分的定义
defaults
# mode语法：mode {http|tcp|health} 。http是七层模式，tcp是四层模式，health是健康检测，返回OK
mode tcp
# 使用127.0.0.1上的syslog服务的local3设备记录错误信息
log 127.0.0.1 local3 err
#if you set mode to http,then you nust change tcplog into httplog
option tcplog
# 启用该项，日志中将不会记录空连接。所谓空连接就是在上游的负载均衡器或者监控系统为了
#探测该服务是否存活可用时，需要定期的连接或者获取某一固定的组件或页面，或者探测扫描
#端口是否在监听或开放等动作被称为空连接；官方文档中标注，如果该服务上游没有其他的负
#载均衡器的话，建议不要使用该参数，因为互联网上的恶意扫描或其他动作就不会被记录下来
option dontlognull
# 定义连接后端服务器的失败重连次数，连接失败次数超过此值后将会将对应后端服务器标记为不可用
retries 3
# 当使用了cookie时，haproxy将会将其请求的后端服务器的serverID插入到cookie中，以保证
#会话的SESSION持久性；而此时，如果后端的服务器宕掉了，但是客户端的cookie是不会刷新的
#，如果设置此参数，将会将客户的请求强制定向到另外一个后端server上，以保证服务的正常
option redispatch
#等待最大时长 When a server's maxconn is reached, connections are left pending in a queue which may be server-specific or global to the backend.
timeout queue 525600m
# 设置成功连接到一台服务器的最长等待时间，默认单位是毫秒
timeout connect 10s
# 客户端非活动状态的超时时长 The inactivity timeout applies when the client is expected to acknowledge or send data.
timeout client 525600m
# Set the maximum inactivity time on the server side.The inactivity timeout applies when the server is expected to acknowledge or send data.
timeout server 525600m
timeout check 5s
maxconn 5120
#---------------------------------------------------------------------
# 配置haproxy web监控，查看统计信息
listen status
bind 0.0.0.0:1080
mode http
log global
stats enable
# stats是haproxy的一个统计页面的套接字，该参数设置统计页面的刷新间隔为30s
stats refresh 30s
stats uri /haproxy-stats
# 设置统计页面认证时的提示内容
stats realm Private lands
# 设置统计页面认证的用户和密码，如果要设置多个，另起一行写入即可
stats auth admin:passw0rd
# 隐藏统计页面上的haproxy版本信息
# stats hide-version
#---------------------------------------------------------------------
listen master
bind *:5000
mode tcp
option tcplog
balance roundrobin
option httpchk OPTIONS /master
http-check expect status 200
default-server inter 3s fall 3 rise 2 on-marked-down shutdown-sessions
server node1 192.168.19.71:5432 maxconn 1000 check port 8008 inter 5000 rise 2 fall 2
server node2 192.168.19.72:5432 maxconn 1000 check port 8008 inter 5000 rise 2 fall 2
server node3 192.168.19.73:5432 maxconn 1000 check port 8008 inter 5000 rise 2 fall 2
listen replicas
bind *:5001
mode tcp
option tcplog
balance roundrobin
option httpchk OPTIONS /replica
http-check expect status 200
default-server inter 3s fall 3 rise 2 on-marked-down shutdown-sessions
server node1 192.168.19.71:5432 maxconn 1000 check port 8008 inter 5000 rise 2 fall 2
server node2 192.168.19.72:5432 maxconn 1000 check port 8008 inter 5000 rise 2 fall 2
server node3 192.168.19.73:5432 maxconn 1000 check port 8008 inter 5000 rise 2 fall 2
3、启动服务并加入开机自启
systemctl start haproxy systemctl enable haproxy systemctl status haproxy 浏览器访问http://192.168.19.72:1080/haproxy-stats输入用户名admin密码passw0rd 这里我们通过5000端口和5001端口分别来提供写服务和读服务,如果需要对数据库写入数据只需要对外提供192.168.216.136:5000即可,可以模拟主库故障，即关闭其中的master节点来验证是否会进行自动主从切换
七、keepalived部署（两个从节点）
1、安装keepalived服务
yum install -y keepalived
2、配置更新
pg-node1
cat keepalived.conf
global_defs {
notification_email {
root@localhost #收邮件人
}
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id master-node
router_id LVS_01
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 150
advert_int 1
authentication {
auth_type PASS
auth_pass 1221
}
virtual_ipaddress {
192.168.19.110/24 dev eth0 label eth0:0
}
}
-------------------------------------------------------------------------------
pg-node2
cat keepalived.conf
!Configuration File for keepalived
global_defs {
notification_email {
root@localhost #收邮件人
}
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id master-node
router_id LVS_02
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1221
}
virtual_ipaddress {
192.168.19.110/24 dev eth0 label eth0:0
}
}
3、启动keepalived服务
systemctl restart keepalived systemctl enable keepalived
4、对外提供访问端口
VIP：192.168.19.110 端口：5000 读写权限 端口：5001 读权限
注：以上部署有个问题就是haproxy与keepalived相互依存的问题，我的观点是除非死机否则不切换，所以我没有做脚本控制，其他要是有问题，欢迎大佬们提提意见哦！！！