I don't expect [moby/moby#24170](https://github.com/moby/moby/issues/24170) to be solved by Docker team on near future so this gist is about looking for least ugly workarounds which are available today and on near future.

# What is possible on Docker 19.03
## Network
It is possible to create overlay network with use user specified subnet.
On this example I create network which is size is two C -class networks ( IP range 10.0.0.0 - 10.0.1.255 )
and force Docker to use IPs from second part of it ( 10.0.1.0 - 10.0.1.255 ).

That way I can make sure that IPs 10.0.0.2 - 10.0.0.254 can be specified to containers and they do not collide with IPs which Docker engine assign for service(s)/container(s).
```bash
docker network create --driver overlay --subnet 10.0.0.0/23 --ip-range 10.0.1.0/24 --gateway 10.0.0.1 --attachable test
```

## Containers
By default containers IP addresses are controlled by Docker engine and those cannot be changed inside of container.
Luckily that behavior can be overridden by adding `NET_ADMIN` capability for container.

### Custom Docker image
So first we need create custom docker image which is able set IP for container when it starts.
That we can do example with Dockerfile like this:
```
FROM ubuntu
RUN apt-get update \
        && apt-get install -y net-tools iputils-ping
COPY /start.sh /
ENTRYPOINT /start.sh
```
and start script like this:
```bash
#!/bin/bash
if [[ -f "${STATIC_IP}" ]]; then
        echo "Using default IP from Docker"
else
        echo "Found static IP: ${STATIC_IP} using it"
        ifconfig eth0 ${STATIC_IP} netmask 255.255.255.0 up
fi
sleep infinity
```
Then just build that with command:
```bash
docker build . -t static-ip
```

### Starting container
Then we can start two containers with commands like these which connects then to overlay network and changes IP addresses inside of the to static ones.
```bash
docker run --name test1 --detach=true --rm --cap-add=NET_ADMIN --network=test -e STATIC_IP=10.0.0.11 static-ip
docker run --name test2 --detach=true --rm --cap-add=NET_ADMIN --network=test -e STATIC_IP=10.0.0.12 static-ip
```

# What will be possible on next version
Above solution solves two issues:
- It sets static IPs for containers.
- It allow containers communicate between Docker nodes using overlay network.

However those containers are not swarm services which means that you lose some control to them.
Luckily I have already implemented [docker/cli#1940](https://github.com/docker/cli/pull/1940) and I'm expecting that it will get merged and released as part of next Docker version.

That makes possible to use swarm stack like this:
```yaml
version: "3.7"
services:
  test1:
    image: static-ip
    environment:
      STATIC_IP: 10.0.0.11
    networks:
      - test
    cap_add:
      - NET_ADMIN
  test2:
    image: static-ip
    environment:
      STATIC_IP: 10.0.0.12
    networks:
      - test
    cap_add:
      - NET_ADMIN

networks:
  test:
   external: true
   name: test
```
and deploy it with command:
```bash
docker stack deploy -c static-ip.yml static-ip
```