Abhay Rana aka Nemo

Learnings from building my own home server

Learnings

I forgot to do this on the last blog post, so here is the list:

  1. archlinux has official packages for intel-microcode-updates.
  2. wireguard is almost there. I’m running openvpn for now, waiting for the stable release.
  3. While traefik is great, I’m concerned about the security model it has for connecting to Docker (uses the docker unix socket over a docker mounted volume, which gives it root access on the host). Scary stuff.
  4. Docker Labels are a great signalling mechanism. Update: After seeing multiple bugs with how traefik uses docker labels, they have limited use-cases but work great in those. Don’t try to over-architect them for all your metadata.
  5. Terraform still needs a lot of work on their docker provider. A lot of updates destroy containers, which should be applied without needing a destroy.
  6. I can’t proxy gitea’s SSH authentication easily, since traefik doesn’t support TCP proxying yet.
  7. The docker_volume resource in terraform is useless, since it doesn’t give you any control over the volume location on the host. (This might be a docker limitation.)
  8. The upload block inside a docker_container resource is a great idea. Lets you push configuration straight inside a container. This is how I push configuration straight inside the traefik container for eg:
    upload {
      content = "${file("${path.module}/conf/traefik.toml")}"
      file    = "/etc/traefik/traefik.toml"
    }
    

Advice

This section is if you’re venturing into a docker-heavy terraform setup:

  1. Use traefik. Will save you a lot of pain with proxying requests.
  2. Repeat the ports section for every IP you want to listen on. CIDRs don’t work.
  3. If you want to run the container on boot, you want the following:
     restart = "unless-stopped"
     destroy_grace_seconds = 10
     must_run = true
    
  4. If you have a single docker_registry_image resource in your state, you can’t run terraform without internet access.
  5. Breaking your docker module into images.tf, volumes.tf, and data.tf (for registry_images) works quite well.
  6. Memory limits on docker containers can be too contrained. Keep an eye on logs to see if anything is getting killed.
  7. Setup Docker TLS auth first. I tried proxying Docker over apache with basic auth, but it didn’t work out well.

MongoDB with forceful server restarts

Since my server gets a forceful restart every few days due to power-cuts (I’m still working on a backup power supply), I faced some issues with MongoDB being unable to recover cleanly. The lockfile would indicate a ungraceful shutdown, and it would require manual repairs, which sometimes failed.

As a weird-hacky-fix, since most of the errors were from the MongoDB WiredTiger engine itself, I hypothesized that switching to a more robust engine might save me from these manual repairs. I switched to MongoRocks, and while it has stopped the issue with repairs, the wiki stil doesn’t like it, and I’m facing this issue: https://github.com/Requarks/wiki/issues/313

However, I don’t have to repair the DB manually, which is a win.

SSHD on specific Interface

My proxy server has the following

eth0 139.59.22.234

And an associated Anchor IP for static IP usecases via Digital Ocean. (10.47.0.5, doesn’t show up in ifconfig).

I wanted to run the following setup:

  • eth0:22 -> sshd
  • Anchor-IP:22 -> simpleproxy -> gitea:ssh

where gitea is the git server hosting git.captnemo.in. This way:

  • I could SSH to the proxy server over 22
  • And directly SSH to the Gitea server over 22 using a different IP address.

Unfortunately, sshd doesn’t allow you to listen on a specific interface, and since the eth0 IP is non-static I can’t rely on it.

As a result, I’ve resorted to just using 2 separate ports:

22 -> simpleproxy -> gitea:ssh 222 -> sshd

There are some hacky ways around this by creating a new service that boots SSHD after network connectivity, but I thought this was much more stable.

Wiki.js public pages

I’m using wiki.js setup at https://wiki.bb8.fun. A specific requirement I had was public pages, so that I could give links to people for specific resources that could be browser without a login.

However, I wanted the default to be authenticated, and only certain pages to be public. The config for this was surprisingly simple:

YAML config

You need to ensure that defaultReadAccess is false:

auth:
  defaultReadAccess: false
  local:
    enabled: true

Guest Access

The following configuration is set for the guest user:

Now any pages created under the /public directory are now browseable by anyone.

Here is a sample page: https://wiki.bb8.fun/public/nebula

Docker CA Cert Authentication

I wrote a script that goes with the docker TLS guide to help you setup TLS authentication

OpenVPN default gateway client side configuration

I’m running a OpenVPN configuration on my proxy server. Howver, I don’t always want to use my VPN as the default route, only when I’m in an untrusted network. I still however, want to be able to connect to the VPN and use it to connect to other clients.

The solution is two-fold:

Server Side

Make sure you do not have the following in your OpenVPN server.conf:

push "redirect-gateway def1 bypass-dhcp"

Client Side

I created 2 copies of the VPN configuration files. Both of the them have identical config, except for this one line:

redirect-gateway def1

If I connect to the VPN config using this configuration, all my traffic is forwarded over the VPN. If you’re using Arch Linux, this is as simple as creating 2 config files:

  • /etc/openvpn/client/one.conf
  • /etc/openvpn/client/two.conf

And running systemctl start openvpn-client@one. I’ve enabled my non-defaut-route VPN service, so it automatically connects to on boot.


If you’re interested in my self-hosting setup, I’m using Terraform + Docker, the code is hosted on the same server, and I’ve been writing about my experience and learnings:

  1. Part 1, Hardware
  2. Part 2, Terraform/Docker
  3. Part 3, Learnings
  4. Part 4, Migrating from Google (and more)
  5. Part 5, Home Server Networking

If you have any comments, reach out to me

Published on December 18, 2017 in homeserver,archlinux,docker,terraform,learnings