With charm-vault version from charmhub/stable rev 5, if one tries to relate with postgresql:db (version 12.8 from charmhub/stable rev 235) when using IPv6, no connection is possible and the hook "db-relation-changed" fails.
Here is how it fails with IPv6:
unit-vault-0: 16:42:37 ERROR unit.vault/0.juju-log db:4: Hook error:
File "/var/lib/juju/agents/unit-vault-0/.venv/lib/python3.8/site-packages/charms/reactive/__init__.py", line 74, in main
File "/var/lib/juju/agents/unit-vault-0/.venv/lib/python3.8/site-packages/charms/reactive/bus.py", line 390, in dispatch
File "/var/lib/juju/agents/unit-vault-0/.venv/lib/python3.8/site-packages/charms/reactive/bus.py", line 359, in _invoke
File "/var/lib/juju/agents/unit-vault-0/.venv/lib/python3.8/site-packages/charms/reactive/bus.py", line 181, in invoke
File "/var/lib/juju/agents/unit-vault-0/charm/reactive/vault_handlers.py", line 313, in create_vault_table
File "/var/lib/juju/agents/unit-vault-0/.venv/lib/python3.8/site-packages/psycopg2/__init__.py", line 127, in connect
psycopg2.OperationalError: FATAL: pg_hba.conf rejects connection for host "2602:fc62:b:1018:1::8957", user "juju_vault", database "vault", SSL on
FATAL: pg_hba.conf rejects connection for host "2602:fc62:b:1018:1::8957", user "juju_vault", database "vault", SSL off
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed Traceback (most recent call last):
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed File "/var/lib/juju/agents/unit-vault-0/charm/hooks/db-relation-changed", line 22, in <module>
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed main()
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed File "/var/lib/juju/agents/unit-vault-0/.venv/lib/python3.8/site-packages/charms/reactive/__init__.py", line 74, in main
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed bus.dispatch(restricted=restricted_mode)
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed File "/var/lib/juju/agents/unit-vault-0/.venv/lib/python3.8/site-packages/charms/reactive/bus.py", line 390, in dispatch
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed _invoke(other_handlers)
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed File "/var/lib/juju/agents/unit-vault-0/.venv/lib/python3.8/site-packages/charms/reactive/bus.py", line 359, in _invoke
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed handler.invoke()
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed File "/var/lib/juju/agents/unit-vault-0/.venv/lib/python3.8/site-packages/charms/reactive/bus.py", line 181, in invoke
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed self._action(*args)
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed File "/var/lib/juju/agents/unit-vault-0/charm/reactive/vault_handlers.py", line 313, in create_vault_table
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed conn = psycopg2.connect(str(pgsql.master))
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed File "/var/lib/juju/agents/unit-vault-0/.venv/lib/python3.8/site-packages/psycopg2/__init__.py", line 127, in connect
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed psycopg2.OperationalError: FATAL: pg_hba.conf rejects connection for host "2602:fc62:b:1018:1::8957", user "juju_vault", database "vault", SSL on
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed FATAL: pg_hba.conf rejects connection for host "2602:fc62:b:1018:1::8957", user "juju_vault", database "vault", SSL off
unit-vault-0: 16:42:37 WARNING unit.vault/0.db-relation-changed
unit-vault-0: 16:42:38 ERROR juju.worker.uniter.operation hook "db-relation-changed" (via explicit, bespoke hook script) failed: exit status 1
root@cloud-vm09:~# grep -hv ^# /etc/postgresql/12/main/pg_{ident,hba}.conf | grep -v ^$
juju_charm postgres postgres
juju_charm root postgres
local all postgres peer map=juju_charm
local all nagios password
local all all peer
local all all reject # Refuse by default
host all all all reject # Refuse by default
When using only IPv4, it works as intended and the proper entries are in pg_hba:
root@juju-556298-0-lxd-0:~# grep -hv ^# /etc/postgresql/12/main/pg_{ident,hba}.conf | grep -v ^$
juju_charm root postgres
juju_charm postgres postgres
local all postgres peer map=juju_charm
local all nagios password
local all all peer
host "vault" "juju_vault" "172.17.18.7/32" md5 # db:4 (vault/0)
host "vault" "juju_vault" "172.17.18.7/32" md5 # db:4 (vault/0)
local all all reject # Refuse by default
host all all all reject # Refuse by default
