Gitea: Ultralight Self-Hosted Git Server

I recently started using Obsidian for keeping notes, tracking projects, and just generally organizing all the information that would otherwise pass into my brain and then fall out the other side. Unlike other similar solutions which operate entirely in The Cloud, Obsidian works with Markdown files stored in a local folder1, which I find to be very attractive. Not only will this allow me to easily transfer my notes between apps if I find something I like better than Obsidian, but it also opens the door to using git to easily back up all this important information.

Some of the contents might be somewhat sensitive, though, and I'm not sure I'd want to keep that data on a service outside of my control. A self-hosted option would be ideal. Gitlab seemed like an obvious choice, but the resource requirements are a bit higher than would be justified by my single-user use case. I eventually came across Gitea, a lightweight Git server with a simple web interface (great for a Git novice like myself!) which boasts the ability to run on a Raspberry Pi. This sounded like a great candidate for running on an Ampere ARM-based compute instance in my Oracle Cloud free tier environment!

In this post, I'll describe what I did to get Gitea up and running on a tiny ARM-based cloud server (though I'll just gloss over the cloud-specific configurations), as well as how I'm leveraging Tailscale to enable SSH Git access without having to expose that service to the internet. I based the bulk of this on the information provided in Gitea's Install With Docker documentation.

Create the server

I'll be deploying this on a cloud server with these specs:

Shape VM.Standard.A1.Flex
Image Ubuntu 22.04
CPU Count 1
Memory (GB) 6
Boot Volume (GB) 50

I've described the process of creating a new instance on OCI in a past post so I won't reiterate that here. The only gotcha this time is switching the shape to VM.Standard.A1.Flex; the OCI free tier allows two AMD Compute VMs (which I've already used up) as well as up to four ARM Ampere A1 instances2.

Prepare the server

Once the server's up and running, I go through the usual steps of applying any available updates:

1sudo apt update
2sudo apt upgrade

Install Tailscale

And then I'll install Tailscale using their handy-dandy bootstrap script:

1curl -fsSL https://tailscale.com/install.sh | sh

When I bring up the Tailscale interface, I'll use the --advertise-tags flag to identify the server with an ACL tag. (Within my tailnet3, all of my other clients are able to connect to devices bearing the cloud tag but cloud servers can only reach back to other devices for performing DNS lookups.)

1sudo tailscale up --advertise-tags "tag:cloud"

Install Docker

Next I install Docker and docker-compose:

1sudo apt install ca-certificates curl gnupg lsb-release
2curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
3echo \
4  "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
5  $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
6sudo apt update
7sudo apt install docker-ce docker-ce-cli containerd.io docker-compose docker-compose-plugin

Configure firewall

This server automatically had an iptables firewall rule configured to permit SSH access. For Gitea, I'll also need to configure HTTP/HTTPS access. As before, I need to be mindful of the explicit REJECT all rule at the bottom of the INPUT chain:

 1$ sudo iptables -L INPUT --line-numbers
 2Chain INPUT (policy ACCEPT)
 3num  target     prot opt source               destination
 41    ts-input   all  --  anywhere             anywhere
 52    ACCEPT     all  --  anywhere             anywhere             state RELATED,ESTABLISHED
 63    ACCEPT     icmp --  anywhere             anywhere
 74    ACCEPT     all  --  anywhere             anywhere
 85    ACCEPT     udp  --  anywhere             anywhere             udp spt:ntp
 96    ACCEPT     tcp  --  anywhere             anywhere             state NEW tcp dpt:ssh
107    REJECT     all  --  anywhere             anywhere             reject-with icmp-host-prohibited

So I'll insert the new rules at line 6:

1sudo iptables -L INPUT --line-numbers
2sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 80 -j ACCEPT
3sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 443 -j ACCEPT

And confirm that it did what I wanted it to:

 1$ sudo iptables -L INPUT --line-numbers
 2Chain INPUT (policy ACCEPT)
 3num  target     prot opt source               destination
 41    ts-input   all  --  anywhere             anywhere
 52    ACCEPT     all  --  anywhere             anywhere             state RELATED,ESTABLISHED
 63    ACCEPT     icmp --  anywhere             anywhere
 74    ACCEPT     all  --  anywhere             anywhere
 85    ACCEPT     udp  --  anywhere             anywhere             udp spt:ntp
 96    ACCEPT     tcp  --  anywhere             anywhere             state NEW tcp dpt:https
107    ACCEPT     tcp  --  anywhere             anywhere             state NEW tcp dpt:http
118    ACCEPT     tcp  --  anywhere             anywhere             state NEW tcp dpt:ssh
129    REJECT     all  --  anywhere             anywhere             reject-with icmp-host-prohibited

That looks good, so let's save the new rules:

1$ sudo netfilter-persistent save
2run-parts: executing /usr/share/netfilter-persistent/plugins.d/15-ip4tables save
3run-parts: executing /usr/share/netfilter-persistent/plugins.d/25-ip6tables save
Cloud Firewall

Of course I will also need to create matching rules in the cloud firewall, but I'm going not going to detail those steps again here. And since I've now got Tailscale up and running I can remove the pre-created rule to allow SSH access through the cloud firewall.

Install Gitea

I'm now ready to move on with installing Gitea itself.

Prepare git user

I'll start with creating a git user. This account will be set as the owner of the data volume used by the Gitea container, but will also (perhaps more importantly) facilitate SSH passthrough into the container for secure git operations.

Here's where I create the account and also generate what will become the SSH key used by the git server:

1sudo useradd -s /bin/bash -m git
2sudo -u git ssh-keygen -t ecdsa -C "Gitea Host Key"

The git user's SSH public key gets added as-is directly to that user's authorized_keys file:

1sudo -u git cat /home/git/.ssh/id_ecdsa.pub | sudo -u git tee -a /home/git/.ssh/authorized_keys
2sudo -u git chmod 600 /home/git/.ssh/authorized_keys

When other users add their SSH public keys into Gitea's web UI, those will get added to authorized_keys with a little something extra: an alternate command to perform git actions instead of just SSH ones:

1command="/usr/local/bin/gitea --config=/data/gitea/conf/app.ini serv key-1",no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-pty <user pubkey>
Not just yet

No users have added their keys to Gitea just yet so if you look at /home/git/.ssh/authorized_keys right now you won't see this extra line, but I wanted to go ahead and mention it to explain the next step. It'll show up later. I promise.

So I'll go ahead and create that extra command:

1cat <<"EOF" | sudo tee /usr/local/bin/gitea
2#!/bin/sh
3ssh -p 2222 -o StrictHostKeyChecking=no git@127.0.0.1 "SSH_ORIGINAL_COMMAND=\"$SSH_ORIGINAL_COMMAND\" $0 $@"
4EOF
5sudo chmod +x /usr/local/bin/gitea

So when I use a git command to interact with the server via SSH, the commands will get relayed into the Docker container on port 2222.

Create docker-compose definition

That takes care of most of the prep work, so now I'm ready to create the docker-compose.yaml file which will tell Docker how to host Gitea.

I'm going to place this in /opt/gitea:

1sudo mkdir -p /opt/gitea
2cd /opt/gitea

And I want to be sure that my new git user owns the ./data directory which will be where the git contents get stored:

1sudo mkdir data
2sudo chown git:git -R data

Now to create the file:

1sudo vi docker-compose.yaml

The basic contents of the file came from the Gitea documentation for Installation with Docker, but I also included some (highlighted) additional environment variables based on the Configuration Cheat Sheet:

docker-compose.yaml:

 1version: "3"
 2
 3networks:
 4  gitea:
 5    external: false
 6
 7services:
 8  server:
 9    image: gitea/gitea:latest
10    container_name: gitea
11    environment:
12      - USER_UID=1003
13      - USER_GID=1003
14      - GITEA__database__DB_TYPE=postgres
15      - GITEA__database__HOST=db:5432
16      - GITEA__database__NAME=gitea
17      - GITEA__database__USER=gitea
18      - GITEA__database__PASSWD=gitea
19      - GITEA____APP_NAME=Gitea
20      - GITEA__log__MODE=file
21      - GITEA__openid__ENABLE_OPENID_SIGNIN=false
22      - GITEA__other__SHOW_FOOTER_VERSION=false
23      - GITEA__repository__DEFAULT_PRIVATE=private
24      - GITEA__repository__DISABLE_HTTP_GIT=true
25      - GITEA__server__DOMAIN=git.bowdre.net
26      - GITEA__server__SSH_DOMAIN=git.bowdre.net.beta.tailscale.net
27      - GITEA__server__ROOT_URL=https://git.bowdre.net/
28      - GITEA__server__LANDING_PAGE=explore
29      - GITEA__service__DISABLE_REGISTRATION=true
30      - GITEA__service_0X2E_explore__DISABLE_USERS_PAGE=true
31      - GITEA__ui__DEFAULT_THEME=arc-green
32
33    restart: always
34    networks:
35      - gitea
36    volumes:
37      - ./data:/data
38      - /home/git/.ssh/:/data/git/.ssh
39      - /etc/timezone:/etc/timezone:ro
40      - /etc/localtime:/etc/localtime:ro
41    ports:
42      - "3000:3000"
43      - "127.0.0.1:2222:22"
44    depends_on:
45      - db
46
47  db:
48    image: postgres:latest
49    container_name: gitea_db
50    restart: always
51    environment:
52      - POSTGRES_USER=gitea
53      - POSTGRES_PASSWORD=gitea
54      - POSTGRES_DB=gitea
55    networks:
56      - gitea
57    volumes:
58      - ./postgres:/var/lib/postgresql/data

Let's go through the extra configs in a bit more detail:

Variable setting Purpose
USER_UID=1003 User ID of the git user on the container host
USER_GID=1003 GroupID of the git user on the container host
GITEA____APP_NAME=Gitea Sets the title of the site. I shortened it from Gitea: Git with a cup of tea because that seems unnecessarily long.
GITEA__log__MODE=file Enable logging
GITEA__openid__ENABLE_OPENID_SIGNIN=false Disable signin through OpenID
GITEA__other__SHOW_FOOTER_VERSION=false Anyone who hits the web interface doesn't need to know the version
GITEA__repository__DEFAULT_PRIVATE=private All repos will default to private unless I explicitly override that
GITEA__repository__DISABLE_HTTP_GIT=true Require that all Git operations occur over SSH
GITEA__server__DOMAIN=git.bowdre.net Domain name of the server
GITEA__server__SSH_DOMAIN=git.bowdre.net.beta.tailscale.net Leverage Tailscale's MagicDNS to tell clients how to SSH to the Tailscale internal IP
GITEA__server__ROOT_URL=https://git.bowdre.net/ Public-facing URL
GITEA__server__LANDING_PAGE=explore Defaults to showing the "Explore" page (listing any public repos) instead of the "Home" page (which just tells about the Gitea project)
GITEA__service__DISABLE_REGISTRATION=true New users will not be able to self-register for access; they will have to be manually added by the Administrator account that will be created during the initial setup
GITEA__service_0X2E_explore__DISABLE_USERS_PAGE=true Don't allow browsing of user accounts
GITEA__ui__DEFAULT_THEME=arc-green Default to the darker theme

Beyond the environment variables, I also defined a few additional options to allow the SSH passthrough to function. Mounting the git user's SSH config directory into the container will ensure that user keys defined in Gitea will also be reflected outside of the container, and setting the container to listen on local port 2222 will allow it to receive the forwarded SSH connections:

1    volumes:
2      [...]
3      - /home/git/.ssh/:/data/git/.ssh
4      [...]
5    ports:
6      [...]
7      - "127.0.0.1:2222:22"

With the config in place, I'm ready to fire it up:

Start containers

Starting Gitea is as simple as

1sudo docker-compose up -d

which will spawn both the Gitea server as well as a postgres database to back it.

Gitea will be listening on port 3000.... which isn't exposed outside of the VM it's running on so I can't actually do anything with it just yet. Let's see about changing that.

Configure Caddy reverse proxy

I've written before about Caddy server and how simple it makes creating a reverse proxy with automatic HTTPS. While Gitea does include built-in HTTPS support, configuring that to work within Docker seems like more work to me.

Install Caddy

So exactly how simple does Caddy make this? Well let's start with installing Caddy on the system:

1sudo apt install -y debian-keyring debian-archive-keyring apt-transport-https
2curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/gpg.key' | sudo gpg --dearmor -o /usr/share/keyrings/caddy-stable-archive-keyring.gpg
3curl -1sLf 'https://dl.cloudsmith.io/public/caddy/stable/debian.deb.txt' | sudo tee /etc/apt/sources.list.d/caddy-stable.list
4sudo apt update
5sudo apt install caddy

Configure Caddy

Configuring Caddy is as simple as creating a Caddyfile:

1sudo vi /etc/caddy/Caddyfile

Within that file, I tell it which fully-qualified domain name(s) I'd like it to respond to (and manage SSL certificates for), as well as that I'd like it to function as a reverse proxy and send the incoming traffic to the same port 3000 that used by the Docker container:

1git.bowdre.net {
2        reverse_proxy localhost:3000
3}

That's it. I don't need to worry about headers or ACME configurations or anything else. Those three lines are all that's required for this use case. It almost seems too easy!

Start Caddy

All that's left at this point is to start up Caddy:

1sudo systemctl enable caddy
2sudo systemctl start caddy
3sudo systemctl restart caddy

I found that the restart is needed to make sure that the config file gets loaded correctly. And after a moment or two, I can point my browser over to https://git.bowdre.net and see the default landing page, complete with a valid certificate.

Configure Gitea

Now that Gitea is installed, I'll need to go through the initial configuration process to actually be able to use it. Fortunately most of this stuff was taken care of by all the environment variables I crammed into the the docker-compose.yaml file earlier. All I really need to do is create an administrative user:

Initial configuration

I can now press the friendly Install Gitea button, and after just a few seconds I'll be able to log in with that new administrator account.

Create user account

I don't want to use that account for all my git actions though so I click on the menu at the top right and select the Site Administration option:

Admin menu

From there I can navigate to the User Accounts tab and use the Create User Account button to make a new account:

User Accounts page

Creating a new user

And then I can log out and log back in with my new non-admin identity!

Add SSH public key

Associating a public key with my new Gitea account will allow me to easily authenticate my pushes from the command line. I can create a new SSH public/private keypair by following GitHub's instructions:

1ssh-keygen -t ed25519 -C "user@example.com"

I'll view the contents of the public key - and go ahead and copy the output for future use:

1; cat ~/.ssh/id_ed25519.pub
2ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIF5ExSsQfr6pAFBEZ7yx0oljSnpnOixvp8DS26STcx2J user@example.com

Back in the Gitea UI, I'll click the user menu up top and select Settings, then the SSH / GPG Keys tab, and click the Add Key button:

User menu
Adding a public key

I can give the key a name and then paste in that public key, and then click the lower Add Key button to insert the new key.

To verify that the SSH passthrough magic I configured earlier is working, I can take a look at git's authorized_keys file:

1; sudo tail -2 /home/git/.ssh/authorized_keys
2# gitea public key
3command="/usr/local/bin/gitea --config=/data/gitea/conf/app.ini serv key-3",no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-pty,no-user-rc,restrict ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIF5ExSsQfr6pAFBEZ7yx0oljSnpnOixvp8DS26STcx2J user@example.com

Hey - there's my public key, being preceded by the customized command I defined earlier. There's one last thing I'd like to do before I get to populating my new server with content...

Configure Fail2ban

I'm already limiting this server's exposure by blocking inbound SSH (except for what's magically tunneled through Tailscale) at the Oracle Cloud firewall, but I still have to have TCP ports 80 and 443 open for the web interface. It would be nice if those web ports didn't get hammered with invalid login attempts.

Fail2ban can help with that by monitoring log files for repeated authentication failures and then creating firewall rules to block the offender.

Installing Fail2ban is simple:

1sudo apt update
2sudo apt install fail2ban

Then I need to tell Fail2ban what to look for when detecting failed logins to Gitea. This can often be a tedious process of crawling through logs looking for example failure messages, but fortunately the Gitea documentation tells me what I need to know.

Specifically, I'll want to watch log/gitea.log for messages like the following:

12018/04/26 18:15:54 [I] Failed authentication attempt for user from xxx.xxx.xxx.xxx
12020/10/15 16:08:44 ...s/context/context.go:204:HandleText() [E] invalid credentials from xxx.xxx.xxx.xxx

So let's create that filter:

1sudo vi /etc/fail2ban/filter.d/gitea.conf

/etc/fail2ban/filter.d/gitea.conf:

1[Definition]
2failregex =  .*(Failed authentication attempt|invalid credentials).* from <HOST>
3ignoreregex =

Next I create the jail, which tells Fail2ban what to do:

1sudo vi /etc/fail2ban/jail.d/gitea.conf

/etc/fail2ban/jail.d/gitea.conf:

1[gitea]
2enabled = true
3filter = gitea
4logpath = /opt/gitea/data/gitea/log/gitea.log
5maxretry = 5
6findtime = 3600
7bantime = 86400
8action = iptables-allports

This configures Fail2ban to watch the log file (logpath) inside the data volume mounted to the Gitea container for messages which match the pattern I just configured (gitea). If a system fails to log in 5 times (maxretry) within 1 hour (findtime, in seconds) then the offending IP will be banned for 1 day (bantime, in seconds).

Then I just need to enable and start Fail2ban:

1sudo systemctl enable fail2ban
2sudo systemctl start fail2ban

To verify that it's working, I can deliberately fail to log in to the web interface and watch /var/log/fail2ban.log:

1; sudo tail -f /var/log/fail2ban.log
22022-07-17 21:52:26,978 fail2ban.filter         [36042]: INFO    [gitea] Found ${MY_HOME_IP}| - 2022-07-17 21:52:26

Excellent, let's now move on to creating some content.

Work with Gitea

Mirror content from GitHub

As an easy first sync, I'm going to simply link a new repository on this server to an existing one I have at GitHub, namely this one which I'm using to track some of my vRealize work. I'll set this up as a one-way mirror so that it will automatically pull in any new upstream changes but new commits made through Gitea will stay in Gitea. And I'll do that by clicking the + button at the top right and selecting New Migration.

New migration menu

Gitea includes support for easy migrations from several content sources:

Migration sources

I pick the GitHub one and then plug in the details of the GitHub repo:

Migrating from GitHub

And after just a few moments, all the content from my GitHub repo shows up in my new Gitea one:

Mirrored repo

You might noticed that I unchecked the Make Repository Private option for this one, so feel free to browse the mirrored repo at https://git.bowdre.net/vPotato/vrealize if you'd like to check out Gitea for yourself.

Create a new repo

The real point of this whole exercise was to sync my Obsidian vault to a Git server under my control, so it's time to create a place for that content to live. I'll go to the + menu again but this time select New Repository, and then enter the required information:

New repository

Once it's created, the new-but-empty repository gives me instructions on how I can interact with it. Note that the SSH address uses the special git.bowdre.net.beta.tailscale.net Tailscale domain name which is only accessible within my tailnet.

Emtpy repository

Now I can follow the instructions to initialize my local Obsidian vault (stored at ~/obsidian-vault/) as a git repository and perform my initial push to Gitea:

1cd ~/obsidian-vault/
2git init
3git add .
4git commit -m "initial commit"
5git remote add origin git@git.bowdre.net.beta.tailscale.net:john/obsidian-vault.git
6git push -u origin main

And if I refresh the page in my browser, I'll see all that content which has just been added:

Populated repo

Conclusion

So now I've got a lightweight, web-enabled, personal git server running on a (free!) cloud server under my control. It's working brilliantly in conjunction with the community-maintained obsidian-git plugin for keeping my notes synced across my various computers. On Android, I'm leveraging the free GitJournal app as a simple git client for pulling the latest changes (as described on another blog I found).


  1. Obsidian does offer a paid Sync plugin for keeping the content on multiple devices in sync, but it's somewhat spendy at $10 month. And much of the appeal of using a Markdown-based system for managing my notes is being in full control of the content. Plus I wanted an excuse to build a git server. ↩︎

  2. The first 3000 OCPU hours and 18,000 GB hours per month are free, equivalent to 4 OCPUs and 24 GB of memory allocated however you see fit. ↩︎

  3. Tailscale's term for the private network which securely links Tailscale-connected devices. ↩︎

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