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

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：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:/<namespace>/<scope>/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:/<namespace>/<scope>/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:/<namespace>/<scope>/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）　　

　　

七、keepalived部署（两个从节点）　　

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