Docker Compose does not create containers in defined subnet - docker

Question

I have a docker-compose file which defines a network subnet:
networks:
<net-name>:
name: my-network
driver: bridge
ipam:
config:
- subnet: 172.21.1.0/16
When i run docker-compose up the created containers (all on the same network) are not in this defined subnet, but on the default 172.21.0.X/16, as seen in the docker network inspect <net-name>:
"IPAM": {
"Driver": "default",
"Options": null,
"Config": [
{
"Subnet": "172.21.1.0/16"
}
]
},
...
"Containers": {
"7fe928549faaa7da71a8b75b668ab6b5dae9e337e8abc7c379b3aa685cccf136": {
"Name": "container1",
"EndpointID": "724c4e86574b72e49afe0729e053d2b7c7285ec07e350f1efb8a3dff9b9f2d22",
"MacAddress": "02:42:ac:15:00:02",
"IPv4Address": "172.21.0.2/16",
"IPv6Address": ""
},
"ead40f068d7a4b657c09fb583bdcc229cd2cda2e46876c0bdc602388f19a15bb": {
"Name": "container2",
"EndpointID": "7759ba9bea74496278f74780c49d94e035d1e9c8c330837ea81e95b4d7485da0",
"MacAddress": "02:42:ac:15:00:03",
"IPv4Address": "172.21.0.3/16",
"IPv6Address": ""
},
"f4c18290c832705d83840108c38769b27f418a2845e92aebcd2afc920c519a95": {
"Name": "container3",
"EndpointID": "7ca9be45cea2f5833ea5f673acccce08721e0bf6fff581dad70da7143bb19e03",
"MacAddress": "02:42:ac:15:00:04",
"IPv4Address": "172.21.0.4/16",
"IPv6Address": ""
}
},
The reason this is a problem for me, is that internally in the containers I listen for specific IP adresses, and not everywhere can I use docker DNS resolution. I also have two compose services, which are separated by these subnets, one on 172.21.0.0/16 and the other on 172.21.1.0/16
How can I enforce compose containers to be created on the compose network subnet?