# LinuxKit on a Mac

We recommend using LinuxKit in conjunction with
[Docker for Mac](https://docs.docker.com/docker-for-mac/install/). For
the time being it's best to be on the latest edge release. `linuxkit
run` uses [HyperKit](https://github.com/moby/hyperkit) and
[VPNKit](https://github.com/moby/vpnkit) and the edge release ships
with updated versions of both.

## Networking

By default, `linuxkit run` creates a VM with a single network
interface which, logically, is attached to a L2 bridge, which also has
the VM used by Docker for Mac attached to it. This means that the LinuxKit
VMs can be accessed from containers running on Docker for Mac.

The LinuxKit VMs have IP addresses on the `192.168.65.0/24` subnet
assigned by a DHCP server part of VPNKit. `192.168.65.1` is reserved
for VPNKit as the default gateway and `192.168.65.2` is used by the
Docker for Mac VM.

By default, LinuxKit VMs get incrementally increasing IP addresses, but you can assign a fixed IP address with `linuxkit run -ip`. It's best to choose an IP address from the DHCP address range above, but care must be taking to avoid clashes of IP address.

### Accessing services

The simplest way to access networking services exposed by a LinuxKit VM is to use a Docker for Mac container.

For example, to access an ssh server in a LinuxKit VM, create a ssh client container from:
```
FROM alpine:edge
RUN apk add --no-cache openssh-client
```
and then run
```
docker build -t ssh .
docker run --rm -ti -v ~/.ssh:/root/.ssh  ssh ssh <IP address of VM>
```


### Forwarding ports to the host

While VPNKit has the general tooling to expose any VMs port on the
localhost (just like it does with containers in Docker for Mac), we
are unlikely to expose this as a general feature in `linuxkit run` as
it is very specific to the macOS. However, you can use a `socat` container to proxy between LinuxKit VMs ports and localhost.  For example, to expose the redis port from the [RedisOS example](../examples/redis-os.yml), use this Dockerfile:
```
FROM alpine:edge
RUN apk add --no-cache socat
ENTRYPOINT [ "/usr/bin/socat" ]
```
and then:
```
docker build -t socat .
docker run --rm -t -d -p 6379:6379 socat tcp-listen:6379,reuseaddr,fork tcp:<IP address of VM>:6379
```