pgadmin can't see postgres when using compose - postgresql

Question

I've successfully created 2 containers for testing:
docker container run --name postgres -p 5432:5432 -e POSTGRES_PASSWORD=password --hostname postgres --network postgres-net -d -v postgres-vol:/var/lib/postgresql/data postgis/postgis
docker container run --name pgadmin4 -p 5050:80 -v pgadmin4:/var/lib/pgadmin -e PGADMIN_DEFAULT_EMAIL=me#gmail.com -e PGADMIN_DEFAULT_PASSWORD=password --hostname pgadmin4 --network postgres-net --detach dpage/pgadmin4
Both are in the bridge network postgres-net and a named volumed has been created for each one of them: pgadmin4 and postgres-vol
❯ docker container inspect postgres --format '{{json .NetworkSettings}}' | jq
{
"Bridge": "",
"SandboxID": "4a06989f7e03c06b89956681e0f3dd4c400cbeba248d0f418ddf03c8b3e5984e",
"HairpinMode": false,
"LinkLocalIPv6Address": "",
"LinkLocalIPv6PrefixLen": 0,
"Ports": {
"5432/tcp": [
{
"HostIp": "0.0.0.0",
"HostPort": "5432"
}
]
},
"Networks": {
"postgres-net": {
"IPAMConfig": null,
"Links": null,
"Aliases": [
"abbecb6784e7",
"postgres"
],
"NetworkID": "15baa0bcadc284342cfd1afde7e7800d1c7aab1045b4cbbca7692293d88cb75a",
"EndpointID": "7afbf3f5ea0f0bdc3396aee45e0158caf784bb5f371ab67fc847a5fc72e85d56",
"Gateway": "172.19.0.1",
"IPAddress": "172.19.0.3",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "xxxxxx",
"DriverOpts": null
}
}
For connecting pgadmin to postgres, I just needed to make reference to the postgres host to make it work.
Then, I decided to move on to compose ...
PGADMIN_EMAIL=me#gmail.com PGADMIN_PASSWORD=password PGPASSWORD=password docker compose -f docker/docker-compose.yml up
...using this compose file:
services:
postgres:
image: postgis/postgis:latest
hostname: postgres
ports:
- '5432:5432'
networks:
- gw-net
environment:
- POSTGRES_PASSWORD=${PGPASSWORD}
volumes:
- postgres-vol:/var/lib/postgresql/data
pgadmin4:
image: dpage/pgadmin4:latest
hostname: pgadmin4
ports:
- '5050:80'
networks:
- postgres-net
environment:
- PGADMIN_DEFAULT_EMAIL=${PGADMIN_EMAIL}
- PGADMIN_DEFAULT_PASSWORD=${PGADMIN_PASSWORD}
volumes:
- pgadmin4:/var/lib/pgadmin
networks:
postgres-net: {}
volumes:
pgadmin4:
external: true
postgres-vol:
external: true
For whatever reason, the pgadmin4-1 container is not able to connect to the postgres-1 container.
{
"Bridge": "",
"SandboxID": "7550d2c28fbc07ab33769c2255aa38ee0ec0c713257aa777e4e9986fd69715fc",
"HairpinMode": false,
"LinkLocalIPv6Address": "",
"LinkLocalIPv6PrefixLen": 0,
"Ports": {
"5432/tcp": [
{
"HostIp": "0.0.0.0",
"HostPort": "5432"
}
]
},
"SandboxKey": "/var/run/docker/netns/7550d2c28fbc",
"SecondaryIPAddresses": null,
"SecondaryIPv6Addresses": null,
"EndpointID": "",
"Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"IPAddress": "",
"IPPrefixLen": 0,
"IPv6Gateway": "",
"MacAddress": "",
"Networks": {
"docker_gw-net": {
"IPAMConfig": null,
"Links": null,
"Aliases": [
"docker-postgres-1",
"postgres",
"03ea9d1f8933"
],
"NetworkID": "591f1440bf5a4b32e3e348b1eccc9e025cb8da05ed5a6423a7768ae9daf969db",
"EndpointID": "f4e78d0b454c5eee9537837464d68006e3bee0799d366415949591db2ff3ed26",
"Gateway": "172.21.0.1",
"IPAddress": "172.21.0.3",
"IPPrefixLen": 16,
"IPv6Gateway": "",
"GlobalIPv6Address": "",
"GlobalIPv6PrefixLen": 0,
"MacAddress": "xxxxxxxx",
"DriverOpts": null
}
}
}
I get this error:
Unable to connect to server:
could not translate host name "docker-postgres-1" to address: Name does not resolve
I also tried using "postgres" without success. I can see that the maintenance database i've specified exists and that the use exists as well.