Connecting to a database in a cluster PostgreSQL
You can connect to Managed Service for PostgreSQL cluster hosts:
- Over the internet, if you configured public access for the appropriate host. You can only connect to these hosts over an SSL connection.
- From Yandex.Cloud virtual machines located in the same virtual network. If the host isn't publicly available, you don't need to use an SSL connection to connect to such VMs.
If public access is only configured for certain hosts in your cluster, automatic master change may make the master unavailable over the internet.
Configuring an SSL certificate
PostgreSQL hosts with public access only support connections with an SSL certificate. You can prepare a certificate as follows:
$ mkdir ~/.postgresql $ wget "https://storage.yandexcloud.net/cloud-certs/CA.pem" -O ~/.postgresql/root.crt $ chmod 0600 ~/.postgresql/root.crt
Connect to the database using the command
To view an example of the command with the host FQDN filled in, open the cluster page in the management console and click Connect.
For hosts with public access, you can only connect over the internet with an SSL certificate.
$ psql "host=<DB host FQDN> \ port=6432 \ sslmode=verify-full \ dbname=<DB name> \ user=<DB user name>"
If you don't need to encrypt traffic within the virtual network when connecting to the database, you can connect to the database without an SSL connection. Pass the
sslmode parameter with the
$ psql "host=<DB host FQDN> \ port=6432 \ sslmode=disable \ dbname=<DB name> \ user=<DB user name>"
Automatic master host selection
To guarantee a connection to the master host, specify the FQDNs of all the cluster hosts in the
host argument and pass the
target_session_attrs=read-write parameter. This parameter is supported by the
libpq library starting from version 10:
psql "host=<host 1 FQDN>,<host 2 FQDN>,<host 3 FQDN> \ port=6432 \ sslmode=verify-full \ dbname=<DB name> \ user= \ target_session_attrs=read-write"
To upgrade the library version used by the
For Debian-based Linux distributions, install the
postgresql-client-10package (for example, using an APT repository).
For operating systems that use RPM packages, a PostgreSQL distribution is available from a YUM repository.
You can find the addresses of all the hosts in the DB cluster on the appropriate cluster page in the management console.
With a driver that supports only one host
If your database connection driver doesn't support passing multiple hosts in the connection string (for example, pgx in Go), you can connect to a special host like
This domain name always indicates the current master in the cluster. For example, you can connect to the master of the cluster with the
c9qash3nb1v9ulc8j9nm ID as follows:
$ psql "host=c-c9qash3nb1v9ulc8j9nm.rw.mdb.yandexcloud.net \ port=6432 \ sslmode=verify-full \ dbname=<DB name> \ user=<DB user name>"