install a patroni cluster with a alrady DB

[emanfeah]

hello ,

i want ask you about if we have already a DataBase (postgresql) in Virtual Machine can we install patroni without loosing the db ? and how we can do that approach on your playbook ..

[vitabaks]

Hello @emanfeah, yes.

In addition to deploying new clusters, this playbook also support the deployment of cluster over already existing and running PostgreSQL. You can convert your basic PostgreSQL installation to a high availability cluster. \ Just specify the variable postgresql_exists=true in the inventory file. Also make sure that the other variables (e.g. postgresql_version, postgresql_data_dir, etc) match your database.

Attention! Your PostgreSQL will be stopped before running in cluster mode (please plan for a short downtime of databases).

[emanfeah]

what about the replicas Vm , its need to install a Postgresql manually Right ? and it will sync ?

[emanfeah]

`ubuntu@patroni1:~/postgresql_cluster$ ansible-playbook deploy_pgcluster.yml 

PLAY [Deploy PostgreSQL HA Cluster (based on "Patroni" and "etcd")] ************************************************************[WARNING]: Unhandled error in Python interpreter discovery for host postgresql_exists=true: Failed to connect to the host via
ssh: ssh: Could not resolve hostname postgresql_exists=true: Name or service not known

TASK [Gathering Facts] *********************************************************************************************************fatal: [postgresql_exists=true]: UNREACHABLE! => {"changed": false, "msg": "Data could not be sent to remote host \"postgresql_exists=true\". Make sure this host can be reached over ssh: ssh: Could not resolve hostname postgresql_exists=true: Name or service not known\r\n", "unreachable": true}
ok: [xxx.8]
ok: [xxx.3]
ok: [xxx.11]

NO MORE HOSTS LEFT *************************************************************************************************************
PLAY RECAP *********************************************************************************************************************xxx.11                 : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
xxx.3                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
xxx.8                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   
postgresql_exists=true     : ok=0    changed=0    unreachable=1    failed=0    skipped=0    rescued=0    ignored=0   `

here i change a inventory file :

[vitabaks]

@emanfeah See example

# PostgreSQL nodes
[master]
10.128.64.140 hostname=pgnode01 postgresql_exists=true

[replica]
10.128.64.142 hostname=pgnode02 postgresql_exists=true
10.128.64.143 hostname=pgnode03 postgresql_exists=true

[vitabaks]

what about the replicas Vm , its need to install a Postgresql manually Right ? and it will sync ?

You can add replicas automatically

# PostgreSQL nodes
[master]
10.128.64.140 hostname=pgnode01 postgresql_exists=true

[replica]
10.128.64.142 hostname=pgnode02 postgresql_exists=false
10.128.64.143 hostname=pgnode03 postgresql_exists=false

Or separately using the playbook add_pgnode.yml (details)