How to Install Reddit-like Content Aggregator Lemmy on Ubuntu 22.04

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How to Install Reddit-like Content Aggregator Lemmy on Ubuntu 22.04

Lemmy is an open-source Reddit-like content aggregator and microblogging platform for the fediverse. It allows you to create and moderate communities and can communicate with other ActivityPub services including Mastodon, Pleroma, and Peertube.

While there are popular instances of Lemmy you can join and use, you can also run your own Lemmy instance for your friends and family. In this tutorial, you will learn how to install Lemmy on an Ubuntu 22.04 server.


  • A server running Ubuntu 22.04.

  • A non-root sudo user.

  • A fully qualified domain name (FQDN) like example.com.

  • Make sure everything is updated.

    $ sudo apt update
    $ sudo apt upgrade

  • Few packages that your system needs.

    $ sudo apt install wget curl nano ufw software-properties-common dirmngr apt-transport-https gnupg2 ca-certificates lsb-release ubuntu-keyring unzip -y

    Some of these packages may already be installed on your system.

Step 1 – Configure Firewall

The first step is to configure the firewall. Ubuntu comes with ufw (Uncomplicated Firewall) by default.

Check if the firewall is running.

$ sudo ufw status

You will get the following output.

Status: inactive

Allow SSH port so that the firewall doesn’t break the current connection upon enabling it.

$ sudo ufw allow OpenSSH

Allow HTTP and HTTPS ports as well.

$ sudo ufw allow http
$ sudo ufw allow https

Enable the Firewall

$ sudo ufw enable
Command may disrupt existing ssh connections. Proceed with operation (y|n)? y
Firewall is active and enabled on system startup

Check the status of the firewall again.

$ sudo ufw status

You should see a similar output.

Status: active

To Action From
-- ------ ----
OpenSSH ALLOW Anywhere
80/tcp ALLOW Anywhere
443 ALLOW Anywhere
OpenSSH (v6) ALLOW Anywhere (v6)
80/tcp (v6) ALLOW Anywhere (v6)
443 (v6) ALLOW Anywhere (v6)

Step 2 – Install Docker and Docker Compose

Ubuntu 22.04 ships with an older version of Docker. To install the latest version, first, import the Docker GPG key.

$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker.gpg

Create a Docker repository file.

$ echo
"deb [arch="$(dpkg --print-architecture)" signed-by=/usr/share/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu
"$(. /etc/os-release && echo "$VERSION_CODENAME")" stable" |
sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Update the system repository list.

$ sudo apt update

Install the latest version of Docker.

$ sudo apt install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Verify that it is running.

$ sudo systemctl status docker
? docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
Active: active (running) since Fri 2023-08-04 07:48:20 UTC; 4min 29s ago
TriggeredBy: ? docker.socket
Docs: https://docs.docker.com
Main PID: 2372 (dockerd)
Tasks: 8
Memory: 23.9M
CPU: 295ms
CGroup: /system.slice/docker.service
??2372 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

By default, Docker requires root privileges. If you want to avoid using sudo every time you run the docker command, add your username to the docker group.

$ sudo usermod -aG docker $(whoami)

You will need to log out of the server and back in as the same user to enable this change or use the following command.

$ su - ${USER}

Confirm that your user is added to the Docker group.

$ groups
navjot wheel docker

Step 3 – Create and download Lemmy files

Create a folder for Lemmy.

$ mkdir ~/lemmy

Switch to the directory.

$ cd ~/lemmy

Grab the custom Nginx file to work with Docker.

$ wget https://raw.githubusercontent.com/LemmyNet/lemmy-ansible/main/templates/nginx_internal.conf

Grab the Docker compose file.

$ wget https://raw.githubusercontent.com/LemmyNet/lemmy-ansible/main/templates/docker-compose.yml

Create a folder for the Pictrs application.

$ mkdir -p volumes/pict-rs

Set the correct permissions for the directory.

$ sudo chown -R 991:991 volumes/pict-rs

Step 4 – Configure Lemmy

Before proceeding with the installation, we need to edit the files we downloaded.

Open the Docker compose file for editing.

$ nano docker-compose.yml

Make the following changes in the file:

  • Replace the variable {{ lemmy_port }} with 8536 in the file.

  • Replace the variable {{ lemmy_docker_image }} with dessalines/lemmy:0.18.3 in the file. You can get the latest version of Lemmy’s Docker image from its Docker Hub page. The page requires you to have a Docker account. Alternatively, you can get the version from its Github releases page.

  • Replace the variable {{ lemmy_docker_ui_image }} with dessalines/lemmy-ui:0.18.3 in the file. Make sure the version matches with Lemmy’s docker image otherwise, it won’t work.

  • Generate an API key for pict-rs using the following command.

    $ openssl rand -base64 32

    The PICTRS__API_KEY key under the environment attribute under the pictrs service is wrongly configured to say it should be the PostgreSQL password. Replace the {{ postgres_password }} variable across the API key variable with the key generated in the above command.

  • Replace the {{ domain }} variable in the file with your fully qualified domain name for your Lemmy instance.

  • Replace the {{ postgres_password }} with a strong password of your choice for the PostgreSQL server.

  • Replace the existing environment variable RUST_LOG with the following.

    - RUST_LOG="warn,lemmy_server=debug,lemmy_api=debug,lemmy_api_common=debug,lemmy_api_crud=debug,lemmy_apub=debug,lemmy_db_schema=debug,lemmy_db_views=debug,lemmy_db_views_actor=debug,lemmy_db_views_moderator=debug,lemmy_routes=debug,lemmy_utils=debug,lemmy_websocket=debug"

  • Add the following section under the hostname property under the PostgreSQL service.

    ] ports:
    # use a different port so it doesnt conflict with potential postgres db running on the host
    - "5433:5432"

Save the file by pressing Ctrl + X and entering Y when prompted once finished. Next, create and open the file lemmy.hjson for editing.

$ nano lemmy.hjson

Paste the following code.

# for more info about the config, check out the documentation
# https://join-lemmy.org/docs/en/administration/configuration.html

database: {
host: "postgres"
user: "lemmy"
password: "yourpsqlpassword"
database: "lemmy"
port: 5432
hostname: "example.com"
pictrs: {
url: "http://pictrs:8080/"
# Set a custom pictrs API key. ( Required for deleting images )
api_key: "lRLcaM5rovxzmztlDvtkGijJyBtg4KlEKC6HRb3dn7s="
email: {
smtp_server: "email-smtp.us-west-2.amazonaws.com:465"
smtp_login: "AmazonSESUserID"
smtp_from_address: "[email protected]"
# Whether or not smtp connections should use tls. Can be none, tls, or starttls
tls_type: "tls"
setup: {
# Username for the admin user
admin_username: "admin"
# Password for the admin user. It must be at least 10 characters.
admin_password: "tf6HHDS4RolWfFhk4Rq9"
# Name of the site (can be changed later)
site_name: "Howtoforge Lemmy"
# Email for the admin user (optional, can be omitted and set later through the website)
admin_email: "[email protected]"

Save the file by pressing Ctrl + X and entering Y when prompted once finished.

The next step is to create a custom PostgreSQL configuration file to optimize the database. Visit the PGTune website to generate values depending on your server size.

Enter the server values and click the Generate button and create the custom configuration.

Create and open the customPostgresql.conf file for editing.

$ nano customPostgresql.conf

Paste the code you got from PGTune.

# DB Version: 15
# OS Type: linux
# DB Type: web
# Total Memory (RAM): 2 GB
# CPUs num: 2
# Connections num: 100
# Data Storage: ssd

max_connections = 100
shared_buffers = 512MB
effective_cache_size = 1536MB
maintenance_work_mem = 128MB
checkpoint_completion_target = 0.9
wal_buffers = 16MB
default_statistics_target = 100
random_page_cost = 1.1
effective_io_concurrency = 200
work_mem = 2621kB
min_wal_size = 1GB
max_wal_size = 4GB

Save the file by pressing Ctrl + X and entering Y when prompted.

Step 5 – Install Lemmy

Now that all files are configured, it is time to run Lemmy. Run the following command to launch the docker containers.

$ docker compose up -d

Check the status of the containers.

$ docker ps
75443bb3db3e nginx:1-alpine "/docker-entrypoint.…" 32 seconds ago Up 29 seconds 80/tcp,>8536/tcp, :::8536->8536/tcp lemmy-proxy-1
8393c8d625af dessalines/lemmy-ui:0.18.1 "docker-entrypoint.s…" 32 seconds ago Up 30 seconds 1234/tcp lemmy-lemmy-ui-1
ea743c8279f7 dessalines/lemmy:0.18.1 "/app/lemmy" 32 seconds ago Up 26 seconds lemmy-lemmy-1
78855ae7871e postgres:15-alpine "docker-entrypoint.s…" 33 seconds ago Up 31 seconds 5432/tcp lemmy-postgres-1
9556b57afdb9 asonix/pictrs:0.4.0 "/sbin/tini -- /usr/…" 33 seconds ago Up 31 seconds 6669/tcp, 8080/tcp lemmy-pictrs-1

You can also check the status using Docker Compose.

$ docker compose ps
lemmy-lemmy-1 dessalines/lemmy:0.18.1 "/app/lemmy" lemmy About a minute ago Up About a minute
lemmy-lemmy-ui-1 dessalines/lemmy-ui:0.18.1 "docker-entrypoint.s…" lemmy-ui About a minute ago Up About a minute 1234/tcp
lemmy-pictrs-1 asonix/pictrs:0.4.0 "/sbin/tini -- /usr/…" pictrs About a minute ago Up About a minute 6669/tcp, 8080/tcp
lemmy-postgres-1 postgres:15-alpine "docker-entrypoint.s…" postgres About a minute ago Up About a minute 5432/tcp
lemmy-proxy-1 nginx:1-alpine "/docker-entrypoint.…" proxy About a minute ago Up About a minute 80/tcp,>8536/tcp, :::8536->8536/tcp

You can test by opening the URL http://<server_IP>:8536/ and you should see Lemmy’s homepage. That concludes everything is okay. The next step is to install Nginx and Certbot to serve Lemmy via a domain name.

Step 6 – Install Nginx

Ubuntu 22.04 ships with an older version of Nginx. To install the latest version, you need to download the official Nginx repository.

Import Nginx’s signing key.

$ curl https://nginx.org/keys/nginx_signing.key | gpg --dearmor
| sudo tee /usr/share/keyrings/nginx-archive-keyring.gpg >/dev/null

Add the repository for Nginx’s stable version.

$ echo "deb [signed-by=/usr/share/keyrings/nginx-archive-keyring.gpg arch=amd64] http://nginx.org/packages/ubuntu `lsb_release -cs` nginx"
| sudo tee /etc/apt/sources.list.d/nginx.list

Update the system repositories.

$ sudo apt update

Install Nginx.

$ sudo apt install nginx

Verify the installation.

$ nginx -v
nginx version: nginx/1.24.0

Start Nginx.

$ sudo systemctl start nginx

Check the status of the service.

$ sudo systemctl status nginx
? nginx.service - nginx - high performance web server
Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
Active: active (running) since Fri 2023-08-04 09:01:56 UTC; 3s ago
Docs: https://nginx.org/en/docs/
Process: 5297 ExecStart=/usr/sbin/nginx -c /etc/nginx/nginx.conf (code=exited, status=0/SUCCESS)
Main PID: 5298 (nginx)
Tasks: 2 (limit: 2308)
Memory: 1.9M
CPU: 7ms
CGroup: /system.slice/nginx.service
??5298 "nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf"
??5299 "nginx: worker process" "" "" "" "" "" "" "" "" "" "" "" "" "" "" "" "" "" "" ""

Step 7 – Install SSL

We need to install Certbot to generate the SSL certificate. You can either install Certbot using Ubuntu’s repository or grab the latest version using the Snapd tool. We will be using the Snapd version.

Ubuntu 22.04 comes with Snapd installed by default. Run the following commands to ensure that your version of Snapd is up to date.

$ sudo snap install core && sudo snap refresh core

Install Certbot.

$ sudo snap install --classic certbot

Use the following command to ensure that the Certbot command can be run by creating a symbolic link to the /usr/bin directory.

$ sudo ln -s /snap/bin/certbot /usr/bin/certbot

Run the following command to generate an SSL Certificate.

$ sudo certbot certonly --nginx --agree-tos --no-eff-email --staple-ocsp --preferred-challenges http -m [email protected] -d example.com

The above command will download a certificate to the /etc/letsencrypt/live/example.com directory on your server.

Generate a Diffie-Hellman group certificate.

$ sudo openssl dhparam -dsaparam -out /etc/ssl/certs/dhparam.pem 4096

Check the Certbot renewal scheduler service.

$ sudo systemctl list-timers

You will find snap.certbot.renew.service as one of the services scheduled to run.

Fri 2023-08-04 09:50:30 UTC 46min left Fri 2023-08-04 01:49:37 UTC 7h ago apt-daily.timer apt-daily.service
Sat 2023-08-05 00:00:00 UTC 14h left Wed 2023-06-28 04:41:28 UTC 5h 7min ago dpkg-db-backup.timer dpkg-db-backup.service
Fri 2023-08-04 18:54:00 UTC 9h left n/a n/a snap.certbot.renew.timer snap.certbot.renew.service

Do a dry run of the process to check whether the SSL renewal is working fine.

$ sudo certbot renew --dry-run

If you see no errors, you are all set. Your certificate will renew automatically.

Step 8 – Configure Nginx

Create and open the file /etc/nginx/conf.d/lemmy.conf for editing.

$ sudo nano /etc/nginx/conf.d/lemmy.conf

Paste the following code in it.

limit_req_zone $binary_remote_addr zone=example.com_ratelimit:10m rate=1r/s;

server {
listen 80;
listen [::]:80;
server_name example.com;
# Hide nginx version
server_tokens off;
location / {
return 301 https://$host$request_uri;

server {
listen 443 ssl http2;
listen [::]:443 ssl http2;
server_name example.com;

access_log /var/log/nginx/lemmy.access.log;
error_log /var/log/nginx/lemmy.error.log;

ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
ssl_trusted_certificate /etc/letsencrypt/live/example.com/chain.pem;

ssl_protocols TLSv1.2 TLSv1.3;
ssl_prefer_server_ciphers off;
ssl_ecdh_curve X25519:prime256v1:secp384r1:secp521r1;
ssl_session_timeout 1d;
ssl_session_cache shared:SSL:10m;
ssl_session_tickets off;
ssl_stapling on;
ssl_stapling_verify on;
ssl_dhparam /etc/ssl/certs/dhparam.pem;
# use https://blog.cloudflare.com/announcing-1111 Cloudfare+Apnic labs, It is free and secure
resolver [2606:4700:4700::1111] [2606:4700:4700::1001] valid=300s;

# Hide nginx version
server_tokens off;

# Enable compression for JS/CSS/HTML bundle, for improved client load times.
# It might be nice to compress JSON, but leaving that out to protect against potential
# compression+encryption information leak attacks like BREACH.
gzip on;
gzip_types text/css application/javascript image/svg+xml;
gzip_vary on;

# Various content security headers
add_header Referrer-Policy "same-origin";
add_header X-Content-Type-Options "nosniff";
add_header X-Frame-Options "DENY";
add_header X-XSS-Protection "1; mode=block";

location / {
proxy_pass http://localhost:8536;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

Notice the root directory to be used in the Nginx configuration is /var/www/html/Lemmy/public/.

Save the file by pressing Ctrl + X and entering Y when prompted once finished.

Open the file /etc/nginx/nginx.conf for editing.

$ sudo nano /etc/nginx/nginx.conf

Add the following line before the line include /etc/nginx/conf.d/*.conf;.

server_names_hash_bucket_size 64;

Save the file by pressing Ctrl + X and entering Y when prompted.

Verify the Nginx configuration file syntax.

$ sudo nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

Restart the Nginx service.

$ sudo systemctl restart nginx

Step 9 – Access Lemmy

Open the URL https://example.com and you will get the following Lemmy homepage.

Click the Login link at the top to bring up the login page.

Enter the credentials used in step 4 and click the Login button to proceed. You will be taken back to the Lemmy homepage. You can start using Lemmy from hereon.

Step 10 – Upgrade Lemmy

To upgrade Lemmy, open the docker-compose.yml file in the ~/lemmy folder.

$ cd ~/lemmy
$ nano docker-compose.yml

Change the version numbers of the apps, Lemmy, Lemmy-UI, and Pictrs in the file. Save the file by pressing Ctrl + X and entering Y when prompted once finished.

Power down the Lemmy containers.

$ docker compose down --remove-orphan

Start the containers back up using the new configuration.

$ docker compose up -d

Step 11 – Backup and Restore Lemmy

To back up Lemmy, we have to take a dump of both the database and the volumes folder. Run the following commands to back up the database.

$ cd ~/lemmy
$ docker compose exec postgres pg_dumpall -c -U lemmy | gzip > lemmy_dump_`date +%Y-%m-%d"_"%H_%M_%S`.sql.gz

In the above command postgres is the service name for PostgreSQL in the compose file.

Next, back up the volumes folder using the following command.

$ sudo rsync -avP volumes ~/backup/lemmy

You can use the following backup script and run it from your local system to take the backup remotely.

# DB Backup
ssh USERNAME@SERVER_IP "docker-compose exec postgres pg_dumpall -c -U lemmy" | gzip > ~/BACKUP_LOCATION/INSTANCE_NAME_dump_`date +%Y-%m-%d"_"%H_%M_%S`.sql.gz

# Volumes folder Backup
rsync -avP -zz --rsync-path="sudo rsync" USERNAME@SERVER_IP:/LEMMY_LOCATION/volumes ~/BACKUP_LOCATION/FOLDERNAME

Restore Lemmy Database

To restore the database on a new Lemmy installation, run the following set of commands.

# Start only the PostgreSQL container first
$ docker compose up -d postgres

# Restore from the .sql.gz backup
$ gunzip < db_dump.sql | docker-compose exec -T postgres psql -U lemmy

# Note: You may need to change the permissions on the postgres directory, depending on your system.
$ chown -R $USER volumes
$ docker compose restart postgres

# Continue with the startup
$ docker compose up -d

If by mistake you have started Lemmy first, you need to clear the existing database using the following commands.

# Drop the existing DB
docker exec -i FOLDERNAME-postgres-1 psql -U lemmy -c "DROP SCHEMA public CASCADE; CREATE SCHEMA public;"

# This also might be necessary when doing a db import with a different password.
docker exec -i FOLDERNAME-postgres-1 psql -U lemmy -c "alter user lemmy with password 'bleh'"

Now you can go through with the restore commands above.


This concludes our tutorial on installing Reddit-like Content Aggregator Lemmy on a Ubuntu 22.04 server. If you have any questions, post them in the comments below.

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