pg_autoctl run¶
pg_autoctl run - Run the pg_autoctl service (monitor or keeper)
Synopsis¶
This commands starts the processes needed to run a monitor node or a keeper
node, depending on the configuration file that belongs to the --pgdata
option or PGDATA
environment variable.
usage: pg_autoctl run [ --pgdata --name --hostname --pgport ]
--pgdata path to data directory
--name pg_auto_failover node name
--hostname hostname used to connect from other nodes
--pgport PostgreSQL's port number
Description¶
When registering Postgres nodes to the pg_auto_failover monitor using the pg_autoctl create postgres command, the nodes are registered with metadata: the node name, hostname and Postgres port.
The node name is used mostly in the logs and pg_autoctl show state commands and helps human administrators of the formation.
The node hostname and pgport are used by other nodes, including the pg_auto_failover monitor, to open a Postgres connection.
Both the node name and the node hostname and port can be changed after the
node registration by using either this command (pg_autoctl run
) or the
pg_autoctl config set command.
Options¶
- --pgdata
Location of the Postgres node being managed locally. Defaults to the environment variable
PGDATA
. Use--monitor
to connect to a monitor from anywhere, rather than the monitor URI used by a local Postgres node managed withpg_autoctl
.- --name
Node name used on the monitor to refer to this node. The hostname is a technical information, and given Postgres requirements on the HBA setup and DNS resolution (both forward and reverse lookups), IP addresses are often used for the hostname.
The
--name
option allows using a user-friendly name for your Postgres nodes.- --hostname
Hostname or IP address (both v4 and v6 are supported) to use from any other node to connect to this node.
When not provided, a default value is computed by running the following algorithm.
We get this machine’s “public IP” by opening a connection to the given monitor hostname or IP address. Then we get TCP/IP client address that has been used to make that connection.
We then do a reverse DNS lookup on the IP address found in the previous step to fetch a hostname for our local machine.
If the reverse DNS lookup is successful , then
pg_autoctl
does a forward DNS lookup of that hostname.
When the forward DNS lookup response in step 3. is an IP address found in one of our local network interfaces, then
pg_autoctl
uses the hostname found in step 2. as the default--hostname
. Otherwise it uses the IP address found in step 1.You may use the
--hostname
command line option to bypass the whole DNS lookup based process and force the local node name to a fixed value.- --pgport
Postgres port to use, defaults to 5432.