PostgreSQL: difficulties with basic pglogical configuration - postgresql

Question

I find official pglogical documentation very confusing. There are too many things that are not clear. Perhaps someone who configured pglogical before could explain how to setup a basic logical replication.
There are two PostgreSQL 9.5 instances - 10.128.0.8 (archlinux1) and 10.128.0.9 (archlinux2). Extension is already installed, CREATE EXTENSION succeeded. There is a table on each instance:
create table test (k text primary key, v text);
I would like to replicate it from archlinux1 to archlinux2.
According to the documentation I should create a provider node:
SELECT pglogical.create_node(
node_name := 'provider1',
dsn := 'host=providerhost port=5432 dbname=db'
);
Should it be executed on master? Should providerhost be 127.0.0.1 or 10.128.0.8? Currenlty replication is allowed only from localhost (accordingly to docs) - should it be changed? My best guess - it should be executed on master like this:
SELECT pglogical.create_node(
node_name := 'provider1',
dsn := 'host=127.0.0.1 port=5432 dbname=eax'
);
create_node
-------------
2976894835
(1 row)
Next:
SELECT pglogical.replication_set_add_all_tables('default', ARRAY['public']);
Should it be executed on master, replica, or both? My best guess - only on master:
SELECT pglogical.replication_set_add_all_tables('default', ARRAY['public']);
replication_set_add_all_tables
--------------------------------
t
(1 row)
Next:
SELECT pglogical.create_node(
node_name := 'subscriber1',
dsn := 'host=thishost port=5432 dbname=db'
);
Apparently it should be executed on replica:
SELECT pglogical.create_node(
node_name := 'subscriber1',
dsn := 'host=127.0.0.1 port=5432 dbname=eax'
);
create_node
-------------
330520249
(1 row)
Next step:
SELECT pglogical.create_subscription(
subscription_name := 'subscription1',
provider_dsn := 'host=providerhost port=5432 dbname=db'
);
Best guess - execute it on replica like this:
SELECT pglogical.create_subscription(
subscription_name := 'subscription1',
provider_dsn := 'host=10.128.0.8 port=5432 dbname=eax'
);
ERROR: could not connect to the postgresql server: could not connect to server: Connection refused
Is the server running on host "10.128.0.8" and accepting
TCP/IP connections on port 5432?
DETAIL: dsn was: host=10.128.0.8 port=5432 dbname=eax
Oops. OK, modifying pg_hba.conf and postgresql.conf properly on master:
# pg_hba.conf
host all all 10.128.0.0/16 md5
# postgresql.conf
listen_addresses = 'localhost,10.128.0.8
Still no luck:
# SELECT pglogical.create_subscription(
subscription_name := 'subscription1',
provider_dsn := 'host=10.128.0.8 port=5432 dbname=eax user=eax password=qwerty'
);
ERROR: could not connect to the postgresql server in replication mode: FATAL: no pg_hba.conf entry for replication connection from host "10.128.0.9", user "eax", SSL off
DETAIL: dsn was: host=10.128.0.8 port=5432 dbname=eax user=eax password=qwerty
Adding to pg_hba.conf on master:
host replication eax 10.128.0.0/16 md5
On replica (success!):
SELECT pglogical.create_subscription(
subscription_name := 'subscription1',
provider_dsn := 'host=10.128.0.8 port=5432 dbname=eax user=eax password=qwerty'
);
create_subscription
---------------------
1763399739
(1 row)
Now on master:
eax=# insert into test values ('aaa', 'bbb');
INSERT 0 1
eax=# select * from test;
k | v
-----+-----
aaa | bbb
(1 row)
On replica:
eax=# select * from test;
k | v
---+---
(0 rows)
Naturally it didn't work. Nothing helpful in logs. Any advice?
UPD: I also created a corresponding issue in pglogical issue tracker.

Answer 1

Perhaps this is a better guide: http://bonesmoses.org/2016/10/14/pg-phriday-perfectly-logical/ - at least it tells you which nodes to execute each command on.

Answer 2

Depesz published an excellent blog post about pglogical configuration https://www.depesz.com/2016/11/08/major-version-upgrading-with-minimal-downtime/

Answer 3

When creating nodes you need to specify an external IP (not localhost)
On the provider
SELECT pglogical.create_node(
node_name := 'provider1',
dsn := 'host=subscriberhost port=5432 dbname=db'
);
On the subscriber
SELECT pglogical.create_node(
node_name := 'subscriber1',
dsn := 'host=providerhost port=5432 dbname=eax'
);