Container-to-container networking on macOS 15 with NoRouter

[afbjorklund]

Regarding https://github.com/apple/container/blob/main/docs/technical-overview.md#macos-15-limitations

Container-to-container communication over the virtual network is not possible.

You can make up for the missing network connectivity between containers, with NoRouter.io:

hosts:
  # host0 is the localhost
  host0:
    vip: "127.0.42.100"
  host1:
    cmd: "container exec -i 20b59a76-b5d7-4d93-8280-23e373221ff7 /root/bin/norouter"
    vip: "127.0.42.101"
    ports: ["8080:127.0.0.1:80"]
  host2:
    cmd: "container exec -i af4c3eb3-6a24-4119-bc8e-7a613e83392b /root/bin/norouter"
    vip: "127.0.42.102"
    ports: ["8080:127.0.0.1:80"]

The norouter binary needs to be installed to the local host and all containers. See Download.

norouter show-installer | container exec

For macOS you first need to add another alias for the loop back address, per Troubleshooting.

sudo ifconfig lo0 alias 127.0.42.100

---

You could give the containers names, or add a user:

https://norouter.io/docs/getting-started/first-example/

It works similar to how it does with Docker or Podman:

https://norouter.io/docs/examples/

This warning message is "normal", until it has been fixed:

level=warning msg="failed to read \"/etc/hosts\"" error="open /etc/hosts: no such file or directory"

• [Bug]: The /etc/hosts file is not created by default #314

It only blocks the WriteEtcHosts feature, not NoRouter.

[afbjorklund]

The WriteEtcHosts: true feature makes it so that you don't need to remember any IP addresses:

127.0.0.1 localhost
192.168.105.203 20b59a76-b5d7-4d93-8280-23e373221ff7
# <Added-by-NoRouter>
127.0.42.100 host0
127.0.42.101 host1
127.0.42.102 host2
# </Added-by-NoRouter>

Instead it uses the host names that you specified in your norouter.yaml file, see Name Resolution

$ more ~/.norouter/agent/hostaliases
host0 127.0.42.100.nip.io
host1 127.0.42.101.nip.io
host2 127.0.42.102.nip.io