How to specify the IP addresses of specific NIC of Postgres Master/Standby servers

[#1]

Hello team,

During settings up Master-Standby Replication for Postgres according to the 'Private Cloud Install-Config Guide', even if there are two NIC devices on both master/standby servers which can communicate with each other, it seems to use always the one communicating with MS server or the IP from /etc/hosts by default. And if we specify the IP of the second NIC at the following steps of 'Set up Master-Standby Replication for Postgres' in the guide,

"Enter server ip of master" and "Enter server ip of standby"

the installation fails with

ERROR: postgres server is down or does not seem be 'slave'
Continue anyhow y/(n) y
Error: Cannot get status of postgres server

I would like to know how we can specify the IP addresses of specific NIC on master/standby postgres servers replication. And then we see the output of the curl command:

curl http://<MS ServerIP>:8080/v1/servers

such as;

...
"externalHostName" : "localhost",
"externalIP" : <PS ServerIP>,
"internalHostName" : "localhost",
"internalIP" : <PS ServerIP>,
...
"type" : [ "postgres-server" ],

Where can we specify the externalIP/internalIP above?

[#2 · Accepted solution]

I could confirm this locally thanks to Naveen and Kaushal from Services team. The PostgreSQL standard config file: /opt/apigee4/data/postgresql/pgdata/pg_hba.conf can specify the IP address to be used for replication as follows whatever from which NIC with configured as eth0, eth1, ....

# TYPE  DATABASE        USER            ADDRESS                 METHOD
# "local" is for Unix domain socket connections only
local   all             all                                     trust
local   all             all                                     md5
# IPv4 local connections:
host    all             all             127.0.0.1/32            md5
host    all             all             0.0.0.0/0            md5
# IPv6 local connections:
host    all             all             ::1/128                 md5

And the 'internalIP' shown on the /servers resource as above is given from the value.