How to Install Mastodon Social Network with Docker on Rocky Linux 9

Mastodon is a free, decentralized, and open-source social network. It was created as an alternative to Twitter. Just like Twitter people can follow each other, and post messages, images, and videos. But unlike Twitter, there is no central store or authority for the content.

Instead, Mastodon operates across thousands of different servers each run by various members of the community. Users signed up on one server can easily connect to users on the other network and follow each other across instances.

Anyone can install their instance of a Mastodon server. This tutorial will teach you how to set up your instance of Mastodon on a server with Rocky Linux 9 using Docker. Docker makes it easy to install Mastodon by containing all the packages and services required in containers.

Prerequisites

• A server running Rocky Linux 9 with a minimum of 2 CPU cores and 2GB of memory. You will need to upgrade the server as per requirements.

• A non-root user with sudo privileges.

• A fully qualified domain name (FQDN) pointing to your server. For our purposes, we will use mastodon.example.com as the domain name.

• Mastodon sends email notifications to users. We will recommend you use a 3rd party Transactional mail service like Mailgun, Sendgrid, Amazon SES, or Sparkpost. The instructions in the guide will be using Amazon SES.

• Make sure everything is updated.

  $ sudo dnf update
  

• Install basic utility packages. Some of them may already be installed.

  $ sudo dnf install wget curl nano unzip yum-utils -y
  

Step 1 - Configure Firewall

The first step is to configure the firewall. Rocky Linux uses Firewalld Firewall. Check the firewall's status.

$ sudo firewall-cmd --state
running

The firewall works with different zones, and the public zone is the default one that we will use. List all the services and ports active on the firewall.

$ sudo firewall-cmd --permanent --list-services

It should show the following output.

cockpit dhcpv6-client ssh

Wiki.js needs HTTP and HTTPS ports to function. Open them.

$ sudo firewall-cmd --permanent --add-service=http
$ sudo firewall-cmd --permanent --add-service=https

Add masquerade, as the application will contact other instances.

$ sudo firewall-cmd --permanent --add-masquerade

Reload the firewall to apply the changes.

$ sudo firewall-cmd --reload

Step 2 - Install Docker and Docker Compose

Rocky Linux ships with an older version of Docker. To install the latest version, first, install the official Docker repository.

$ sudo yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo

Install the latest version of Docker.

$ sudo dnf install docker-ce docker-ce-cli containerd.io

You may get the following error while trying to install Docker.

ror: 
 Problem: problem with installed package buildah-1:1.26.2-1.el9_0.x86_64
  - package buildah-1:1.26.2-1.el9_0.x86_64 requires runc >= 1.0.0-26, but none of the providers can be installed
  - package containerd.io-1.6.9-3.1.el9.x86_64 conflicts with runc provided by runc-4:1.1.3-2.el9_0.x86_64
  - package containerd.io-1.6.9-3.1.el9.x86_64 obsoletes runc provided by runc-4:1.1.3-2.el9_0.x86_64
  - cannot install the best candidate for the job

Use the following command if you get the error above.

$ sudo dnf install docker-ce docker-ce-cli containerd.io docker-compose-plugin --allowerasing

Enable and run the Docker daemon.

$ sudo systemctl enable docker --now

Verify that it is running.

? docker.service - Docker Application Container Engine
     Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
     Active: active (running) since Sat 2022-11-12 00:19:44 UTC; 6s ago
TriggeredBy: ? docker.socket
       Docs: https://docs.docker.com
   Main PID: 99263 (dockerd)
      Tasks: 8
     Memory: 28.1M
        CPU: 210ms
     CGroup: /system.slice/docker.service
             ??99263 /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 - Preparing for Installation

The default limit of the mmap counts is very low for Elasticsearch. Run the following command to check the default value.

$ sysctl vm.max_map_count

You will get the following output.

vm.max_map_count = 65530

Increase the value using the following commands.

$ echo "vm.max_map_count=262144" | sudo tee /etc/sysctl.d/90-max_map_count.conf
$ sudo sysctl --load /etc/sysctl.d/90-max_map_count.conf

Configure SELinux to allow network connections.

$ sudo setsebool -P httpd_can_network_connect 1

Step 4 - Install Mastodon

Create Directories and Set Ownerships

Create directories for Mastodon and related services.

$ sudo mkdir -p /opt/mastodon/database/{postgresql,pgbackups,redis,elasticsearch}
$ sudo mkdir -p /opt/mastodon/web/{public,system}
$ sudo mkdir -p /opt/mastodon/branding

Set proper ownerships to the Elasticsearch, web, and backup directories.

$ sudo chown 991:991 /opt/mastodon/web/{public,system}
$ sudo chown 1000 /opt/mastodon/database/elasticsearch
$ sudo chown 70:70 /opt/mastodon/database/pgbackups

Switch to the Mastodon directory.

$ cd /opt/mastodon

Create environment and docker compose files

Create environment files for the application and the database.

$ sudo touch application.env database.env

Create and open the Docker compose file for editing.

$ sudo nano docker-compose.yml

Paste the following code in it.

version: '3'

services:
  postgresql:
    image: postgres:15-alpine
    env_file: database.env
    restart: always
    shm_size: 512mb
    healthcheck:
      test: ['CMD', 'pg_isready', '-U', 'postgres']
    volumes:
      - postgresql:/var/lib/postgresql/data
      - pgbackups:/backups
    networks:
      - internal_network

  redis:
    image: redis:7-alpine
    restart: always
    healthcheck:
      test: ['CMD', 'redis-cli', 'ping']
    volumes:
      - redis:/data
    networks:
      - internal_network

  redis-volatile:
    image: redis:7-alpine
    restart: always
    healthcheck:
      test: ['CMD', 'redis-cli', 'ping']
    networks:
      - internal_network

  elasticsearch:
    image: docker.elastic.co/elasticsearch/elasticsearch:7.17.7
    restart: always
    env_file: database.env
    environment:
      - cluster.name=elasticsearch-mastodon
      - discovery.type=single-node
      - bootstrap.memory_lock=true
      - xpack.security.enabled=true
      - ingest.geoip.downloader.enabled=false
    ulimits:
      memlock:
        soft: -1
        hard: -1
    healthcheck:
      test: ["CMD-SHELL", "nc -z elasticsearch 9200"]
    volumes:
      - elasticsearch:/usr/share/elasticsearch/data
    networks:
      - internal_network

  website:
    image: tootsuite/mastodon:v4.0.2
    env_file:
      - application.env
      - database.env
    command: bash -c "bundle exec rails s -p 3000"
    restart: always
    depends_on:
      - postgresql
      - redis
      - redis-volatile
      - elasticsearch
    ports:
      - '127.0.0.1:3000:3000'
    networks:
      - internal_network
      - external_network
    healthcheck:
      test: ['CMD-SHELL', 'wget -q --spider --proxy=off localhost:3000/health || exit 1']
    volumes:
      - uploads:/mastodon/public/system

  shell:
    image: tootsuite/mastodon:v4.0.2
    env_file:
      - application.env
      - database.env
    command: /bin/bash
    restart: "no"
    networks:
      - internal_network
      - external_network
    volumes:
      - uploads:/mastodon/public/system
      - static:/static

  streaming:
    image: tootsuite/mastodon:v4.0.2
    env_file:
      - application.env
      - database.env
    command: node ./streaming
    restart: always
    depends_on:
      - postgresql
      - redis
      - redis-volatile
      - elasticsearch
    ports:
      - '127.0.0.1:4000:4000'
    networks:
      - internal_network
      - external_network
    healthcheck:
      test: ['CMD-SHELL', 'wget -q --spider --proxy=off localhost:4000/api/v1/streaming/health || exit 1']

  sidekiq:
    image: tootsuite/mastodon:v4.0.2
    env_file:
      - application.env
      - database.env
    command: bundle exec sidekiq
    restart: always
    depends_on:
      - postgresql
      - redis
      - redis-volatile
      - website
    networks:
      - internal_network
      - external_network
    healthcheck:
      test: ['CMD-SHELL', "ps aux | grep '[s]idekiq\ 6' || false"]
    volumes:
      - uploads:/mastodon/public/system

networks:
  external_network:
  internal_network:
  	 #internal:true

volumes:
  postgresql:
    driver_opts:
      type: none
      device: /opt/mastodon/database/postgresql
      o: bind
  pgbackups:
    driver_opts:
      type: none
      device: /opt/mastodon/database/pgbackups
      o: bind
  redis:
    driver_opts:
      type: none
      device: /opt/mastodon/database/redis
      o: bind
  elasticsearch:
    driver_opts:
      type: none
      device: /opt/mastodon/database/elasticsearch
      o: bind
  uploads:
    driver_opts:
      type: none
      device: /opt/mastodon/web/system
      o: bind
  static:
    driver_opts:
      type: none
      device: /opt/mastodon/web/public
      o: bind

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

At the time of writing the tutorial, the latest available version of Mastodon is v4.0.2. Check the Mastodon GitHub Releases page and adjust the version in the Docker compose file appropriately. We are also using the latest versions of PostgreSQL and Redis. You can adjust them as per your requirements. We are using Elasticsearch 7.x at the moment. There is no major version of Elasticsearch you can follow on the Docker Hub page, so you will have to keep updating it manually for the security updates related to Java.

That internal: true doesn’t work with firewalld, which is why it is commented out in the file above. If this is ever fixed, you may be able to re-add that additional restriction.

Create Application Secrets

The next step is to create application secret values.

Generate SECRET_KEY_BASE and OTP_SECRET values by running the following command twice. The first time will take some time as it will pull the images.

$ docker compose run --rm shell bundle exec rake secret

You can also use the openssl utility for the same.

$ openssl rand -hex 64

Generate VAPID_PRIVATE_KEY and VAPID_PUBLIC_KEY values by using the following command.

$ docker compose run --rm shell bundle exec rake mastodon:webpush:generate_vapid_key 

You will get a similar output.

VAPID_PRIVATE_KEY=u2qsCs5JdmdmMLnUuU0sgmFGvZedteJz-lFB_xF4_ac=
VAPID_PUBLIC_KEY=BJXjE2hIXvFpo6dnHqyf1i-2PcP-cBoL95UCmhhxwlAgtFw_vnrYp4GBneR7_cmI9LZUYjHFh-TBAPSb9WTqH9A=

Use the openssl utility to generate PostgreSQL and Elasticsearch passwords.

$ openssl rand -hex 15

Mastodon Environment Files

Open the application.env file for editing.

$ sudo nano application.env

Paste the following lines in it.

# environment
RAILS_ENV=production
NODE_ENV=production

# domain
LOCAL_DOMAIN=mastodon.example.com

# redirect to the first profile
SINGLE_USER_MODE=false

# do not serve static files
RAILS_SERVE_STATIC_FILES=false

# concurrency
WEB_CONCURRENCY=2
MAX_THREADS=5

# pgbouncer
#PREPARED_STATEMENTS=false

# locale
DEFAULT_LOCALE=en

# email, not used
SMTP_SERVER=email-smtp.us-west-2.amazonaws.com
SMTP_PORT=587
SMTP_LOGIN=AKIA3FIG4NVFNSC3AHXE
SMTP_PASSWORD=BHM4MVOjBmnGhSJ9lH3PAXKJ/9AiLWcUghG/kEN2kkFo
[email protected]

# secrets
SECRET_KEY_BASE=c09fa403575e0b431e54a2e228f20cd5a5fdfdbba0da80598959753b829a4e3c0266eedbac7e3cdf9f3345db36c56302c0e1bc5bfc8c5d516be59a2c41de7e37
OTP_SECRET=febb7dbb0d3308094083733fc923a430e52ccec767d48d7d2e0c577bfcb6863dbdfc920b1004b1f8c2967b9866bd7a0b4a15460f9fc7687aa4a42acf54e5a3d4

# Changing VAPID keys will break push notifications
VAPID_PRIVATE_KEY=13RgrfOY2tkwuUycylDPOkoHennkJ0ZAPV_fUwDy7-g=
VAPID_PUBLIC_KEY=BDAQuGwPbh1kbCV904adYXHvz9lLRaJHkiQkihRDPyBn3QmkAYbR21WHYoP8TkyG6dylG6IXpEVfLwdoW7fJVns=

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

Open the database.env file for editing.

$ sudo nano database.env

Paste the following lines in it.

# postgresql configuration
POSTGRES_USER=mastodon
POSTGRES_DB=mastodon
POSTGRES_PASSWORD=15ff12dcb93aa60680d2aadb4032ee
PGPASSWORD=15ff12dcb93aa60680d2aadb4032ee
PGPORT=5432
PGHOST=postgresql
PGUSER=mastodon

# pgbouncer configuration
#POOL_MODE=transaction
#ADMIN_USERS=postgres,mastodon
#DATABASE_URL="postgres://mastodon:15ff12dcb93aa60680d2aadb4032ee@postgresql:5432/mastodon"

# elasticsearch
ES_JAVA_OPTS=-Xms512m -Xmx512m
ELASTIC_PASSWORD=13382e99f6b2d4dc7f3d66e4b9872d

# mastodon database configuration
#DB_HOST=pgbouncer
DB_HOST=postgresql
DB_USER=mastodon
DB_NAME=mastodon
DB_PASS=15ff12dcb93aa60680d2aadb4032ee
DB_PORT=5432

REDIS_HOST=redis
REDIS_PORT=6379

CACHE_REDIS_HOST=redis-volatile
CACHE_REDIS_PORT=6379

ES_ENABLED=true
ES_HOST=elasticsearch
ES_PORT=9200
ES_USER=elastic
ES_PASS=13382e99f6b2d4dc7f3d66e4b9872d

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

Prepare Mastodon

Get the static files ready to be served by Nginx.

$ docker compose run --rm shell bash -c "cp -r /opt/mastodon/public/* /static/"

Bring up the data layer.

$ docker compose up -d postgresql redis redis-volatile

Check the status of the containers.

$ watch docker compose ps

Wait for running (healthy), then press Ctrl + C and initialize the database using the following command.

$ docker compose run --rm shell bundle exec rake db:setup

Step 5 - Install Nginx

Rocky Linux ships with an older version of Nginx. You need to download the official Nginx repository to install the latest version.

Create and open the /etc/yum.repos.d/nginx.repo file for creating the official Nginx repository.

$ sudo nano /etc/yum.repos.d/nginx.repo

Paste the following code in it.

[nginx-stable]
name=nginx stable repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=1
enabled=1
gpgkey=https://nginx.org/keys/nginx_signing.key
module_hotfixes=true

[nginx-mainline]
name=nginx mainline repo
baseurl=http://nginx.org/packages/mainline/centos/$releasever/$basearch/
gpgcheck=1
enabled=0
gpgkey=https://nginx.org/keys/nginx_signing.key
module_hotfixes=true

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

Install the Nginx server.

$ sudo dnf install nginx

Verify the installation.

$ nginx -v
nginx version: nginx/1.22.1

Enable and start the Nginx server.

$ sudo systemctl enable nginx --now

Check the status of the server.

$ sudo systemctl status nginx
? nginx.service - nginx - high performance web server
     Loaded: loaded (/usr/lib/systemd/system/nginx.service; enabled; vendor preset: disabled)
     Active: active (running) since Sun 2022-11-13 13:49:55 UTC; 1s ago
       Docs: http://nginx.org/en/docs/
    Process: 230797 ExecStart=/usr/sbin/nginx -c /etc/nginx/nginx.conf (code=exited, status=0/SUCCESS)
   Main PID: 230798 (nginx)
      Tasks: 3 (limit: 12355)
     Memory: 2.8M
        CPU: 13ms
     CGroup: /system.slice/nginx.service
             ??230798 "nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf"
             ??230799 "nginx: worker process"
             ??230800 "nginx: worker process"

Step 6 - Install SSL

Certbot tool generates SSL certificates using Let's Encrypt API. It requires the EPEL repository to work.

$ sudo dnf install epel-release

We will use Snapd to install Certbot. Install Snapd.

$ sudo dnf install snapd

Enable and Start the Snap service.

$ sudo systemctl enable snapd --now

Install the Snap core package.

$ sudo snap install core
$ sudo snap refresh core

Create necessary links for Snapd to work.

$ sudo ln -s /var/lib/snapd/snap /snap
$ echo 'export PATH=$PATH:/var/lib/snapd/snap/bin' | sudo tee -a /etc/profile.d/snapd.sh

Issue the following command to install Certbot.

$ sudo snap install --classic certbot

Enable Certbot by creating the symlink to its executable.

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

Generate the SSL certificate.

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

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

Generate a Diffie-Hellman group certificate.

$ sudo openssl dhparam -dsaparam -out