Start patroni

Executed by the root user to start patroni as a service

After configuration, you must reload, if you change the configuration in the middle, you must also reload, otherwise it will not be recognized.

systemctl daemon-reload

Execute as root user

systemctl start patroni   

Check the startup status

systemctl status patroni –l

The following display means the startup is successful.

[shan2@host227 ~]$ systemctl status patroni –l
● patroni.service - Runners to orchestrate a high-availability AntDB5.0
   Loaded: loaded (/usr/lib/systemd/system/patroni.service; disabled; vendor preset: disabled)
   Active: active (running) since Fri 2022-08-05 17:40:21 CST; 2 days ago
 Main PID: 179523 (patroni)
    Tasks: 12
   Memory: 54.9M
   CGroup: /system.slice/patroni.service
           ├─179523 /usr/local/bin/python3.7 /usr/local/bin/patroni /etc/patroni.yml
           ├─179905 /data/shan2/pgsql_adb/bin/postgres -D /data/shan2/pgdata --config-file=/data/shan2/pgdata/p...
           ├─179908 postgres: antdb-cluster: startup   recovering 000000040000000000000005
           ├─179910 postgres: antdb-cluster: checkpointer   
           ├─179911 postgres: antdb-cluster: background writer   
           ├─179912 postgres: antdb-cluster: stats collector   
           ├─179917 postgres: antdb-cluster: shan2 postgres 10.20.16.227(56482) idle
           └─179927 postgres: antdb-cluster: walreceiver   streaming 0/50010D0
Unit \xe2\x80\x93l.service could not be found.

If the startup fails, you can manually execute the ExecStart configuration in the service configuration file above to manually start the service to see the error report.

/usr/local/bin/patroni /etc/patroni.yml

Or

The patroni log is in the system log, if there is a problem, you can go through the log error reporting to investigate

tail -f /var/log/messages

After successful installation, check the status of the cluster.

[root@host228 shan2]# patronictl -c /etc/patroni.yml list
+------------+--------------------+--------------+---------+----+-----------+-----------------+
| Member     | Host               | Role         | State   | TL | Lag in MB | Pending restart |

Cluster: antdb-cluster (7127106860783255508) --+---------+----+-----------+-----------------+
| adbnode_01 | 10.20.16.227:40571 | Sync Standby | running |  4 |         0 | *               |
| adbnode_02 | 10.20.16.228:40571 | Replica      | running |  4 |         0 | *               |
| adbnode_03 | 10.20.16.214:40571 | Leader       | running |  4 |           | *               |
+------------+--------------------+--------------+---------+----+-----------+-----------------+

Some common operations of patroni

patronictl to view cluster information

patronictl -c /etc/patroni.yml list

Restart the cluster, postgres-cluster is the cluster name

patronictl -c /etc/patroni.yml restart postgres-cluster

Restart the nodes

patronictl -c /etc/patroni.yml restart postgres-cluster pgnode02

Reinitialize the nodes

patronictl -c /etc/patroni.yml reinit postgres-cluster pgnode02

Send a SQL command

patronictl -c /etc/patroni.yml query postgres-cluster --command 'select version() ' -d postgres

version

PostgreSQL 13.3 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44), 64-bit

Get the master node dsn information

patronictl -c /etc/patroni.yml dsn postgres-cluster
host=10.19.32.118 port=55551

Manually switchover a node

patronictl -c /etc/patroni.yml switchover

Manually failover a node

patronictl -c /etc/patroni.yml failover

Delete cluster information in DCS

patronictl -c /etc/patroni.yml remove postgres-cluster

• Add patroni and database nodes

• Install antdb, patroni on the new node

• Provide authentication of the new node on the corresponding existing node (pg_hba.conf)

• Copy the yml file to the new node

• Modify the yml file of the new node

 name: antdb120
tags:
replicatefrom: antdb119 ###Select the cascade slave node, the default is to synchronize to the master node
restapi:
listen: 10.21.20.120:8008
connect_address: 10.21.20.120:8008
postgresql:
listen: 0.0.0.0:6432
connect_address: 10.21.20.120:6432
data_dir: /home/antdb/datafile

• Start patroni

 sudo systemctl status patroni -l
sudo journalctl -f -u patroni  

 The patroni log is in the system log, if there is a problem, you can go through the log error reporting to investigate

 tail -f /var/log/messages

Build high availability under ipv6

The steps to build high availability under Ipv6 are the same as the overall steps above, except that the ip address part needs to be changed, as described below.