Configure etcd's service

Executed by root user

cat > /etc/systemd/system/etcd.service <<EOF
[Unit]
Description=Etcd Server
After=network.target
After=network-online.target
Wants=network-online.target

[Service]
User=root
Type=notify
WorkingDirectory=/var/lib/etcd/
ExecStart=/bin/etcd --config-file=/etc/etcd/conf.yaml
Restart=on-failure
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

Start etcd

Start etcd as a service

Executed by root user

systemctl daemon-reload

Open the port, the non-default port must remember to open, otherwise systemctl start etcd will fail

systemctl enable etcd   #After enable, etcd will start automatically when the host is booted.

Execute as antdb user

systemctl start etcd    If it's already on at the beginning, then systemctl restart etcd
systemctl status etcd

Check the status of etcd cluster

systemctl status etcd

Expected output.

[root@host227 ~]# systemctl status etcd
● etcd.service - Etcd Server
   Loaded: loaded (/etc/systemd/system/etcd.service; disabled; vendor preset: disabled)
   Active: active (running) since Mon 2022-08-01 17:11:38 CST; 4min 3s ago
 Main PID: 25631 (etcd)
    Tasks: 46
   Memory: 31.1M
   CGroup: /system.slice/etcd.service
           └─25631 /bin/etcd --config-file=/etc/etcd/conf.yaml

After etcd is configured on all 3 hosts, you can check the status of the etcd cluster

etcdctl --endpoints=http://127.0.0.1:12379 member list

Expected output

[root@host227 ~]# etcdctl --endpoints=http://127.0.0.1:12379 member list
88b36252d4fcd138: name=etcd-2 peerURLs=http://10.20.16.228:12380 clientURLs=http://10.20.16.228:12379 isLeader=false
9ad1f6e716a2ebe6: name=etcd-1 peerURLs=http://10.20.16.227:12380 clientURLs=http://10.20.16.227:12379 isLeader=true
fc652d5e31669223: name=etcd-3 peerURLs=http://10.20.16.214:12380 clientURLs=http://10.20.16.214:12379 isLeader=false

Manage the cluster with Patroni

The following operations need to be performed on all 3 hosts, modify the configuration according to the actual situation.

Configure patroni

Create the file /etc/patroni.yml and configure it as follows.

Executed by root user.

cat > /etc/patroni.yml <<EOF
scope: antdb-cluster        #        Naming of clusters
namespace: /antdb/        # Here the default is service, if it is not set, it will be /service/.
name: adbnode_01           #   Node names, which need to be different for each node

restapi:  
  listen: 10.20.16.227:8008              # Change to actual ip
  connect_address: 10.20.16.227:8008    # Change to actual ip

etcd:
  hosts: 10.20.16.227:12379,10.20.16.228:12379,10.20.16.214:12379

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: 15
    loop_wait: 5
    retry_timeout: 5
    maximum_lag_on_failover: 1048576
    master_start_timeout: 300
    synchronous_mode: true
    postgresql:
      use_pg_rewind: true
      parameters:
         listen_addresses: "*"
         port: 40571     # Change to the actual AntDB port number
         wal_level: logical        #patroni's stream replication level requires logical
         log_directory: "pg_log"
         log_destination: "csvlog"
         hot_standby: "on"
         wal_keep_size: 10240
         max_wal_senders: 10

postgresql:
  listen: 10.20.16.227:40571       # Change to actual ip and AntDB port
  connect_address: 10.20.16.227:40571   # Change to actual ip and AntDB port
  data_dir: /data/shan2/pgdata      # Change to the actual data catalog
  bin_dir: /data/shan2/pgsql_adb/bin   # Change to the actual installation directory
  pgpass: /data/shan2/.pgpass   # Modify it to an actual .pgpass file. pgpass cannot be in the same directory as pgdata.
  authentication:         # Change to actual username and password
    replication:
      username: replicator          
      password: antdb
    superuser:
      username: shan
      password: shan@123
  parameters:
    unix_socket_directories: '/tmp'

tags:
    nofailover: false
    noloadbalance: false
    clonefrom: false
    nosync: false
EOF

The above configuration is modified according to the actual situation.

Configure service for patroni

Executed by the root user.

Note that the User and Group users here are the same as the AntDB installation users.

cat > /usr/lib/systemd/system/patroni.service <<EOF

[Unit]
Description=Runners to orchestrate a high-availability AntDB5.0
After=syslog.target network.target

[Service]
Type=simple
User=shan2
Group=shan2
ExecStart=/usr/local/bin/patroni /etc/patroni.yml
KillMode=process
TimeoutSec=30
Restart=no

[Install]
WantedBy=multi-user.target
EOF