Setup mdns on nerves & elixir project

Nerves Forum Nerves Questions / Help
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I’m setting up a project using nerves and phoenix in a Raspberry Pi 3. I’m using nerves_init_gadget and I have this configuration:

config :nerves_init_gadget,
  ifname: "wlan0",
  address_method: :dhcp,
  mdns_domain: "nerves.local",
  node_name: "test_app",
  node_host: :mdns_domain,
  ssh_console_port: 22

I’ve being able to deploy, and the app is accessible on the device ip, but I can’t resolve nerves.local

I can’t figure out how this works from the mdns docs.

Should I do something on the router?

my resolv.conf contains the gateway nameserver: 192.168.1.1

Thanks!

2

Hi Adrián!

nerves_init_gadget is most useful for projects on gadget capable hardware like the Raspberry Pi Zero. The Pi 3 can’t do gadget mode, which would give you the networking over usb that I think you may be expecting.

Can you describe a little more about your project setup? Namely, what’s your host OS and how are you networking the two devices together? If it’s over WiFi, there may be some additional things your DNS server or host OS need in order for mdns to work so it’s delpful to know more context.

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3

Hi @tmecklem, thanks for your answer!

understood about nerves_init_gadget, I used it because it set up all the network and mdnds. Do you recommend me to use those packages instead of nerves_init_gadget?

My test setup is using wifi, but I haven’t decided yet if on production will be via wifi or ethernet. Probably a mix of them depending on my customer’s networks.

My host OS is ArchLinux, the host is connected via ethernet, and the Raspberry Pi over wifi as I mentioned.

My idea is to connect the device in my customer’s location and ask use mdnds to setup a hostname like: http://myapp for using it. I’d need to know what changes I need on the router or the hosts. For my customers I could have windows, macOS and Linux hosts.

Thanks a lot!

4

I use a very similar config, and i get mdns on my rpi3 via wifi, and i also run arch linux. Have you tried getting Mdns working before this? I found i had to change a few configurations and install a few packages to get mdns to work.

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5

I didn’t know I had to install some packages in order to make it work, thanks!

I followed these instructions and it worked: Avahi - ArchWiki

I have other questions though.

  1. http://nerves.local works on the host, but not on android phones

  2. If I want to use GitHub - rosetta-home/mdns: basic mdns server and discovery client (and forget about nerves_init_gadget), the docs says:

To start the server, call Mdns.Server.start

but where? I can’t find an example of how to use it.

  1. Once the device starts, I can connect to a iex shell with ssh nerves.local. Is it possible to access the started mddns server that nerves_init_gadget started?

Thanks!

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