# Installing on CentOS 7
## Installation

This guide is a step-by-step installation guide for CentOS 7. It also assumes that you have administrative rights, either as root or a user with [sudo permissions](https://www.digitalocean.com/community/tutorials/how-to-create-a-sudo-user-on-centos-quickstart). If you want to run this guide with root, ignore the `sudo` at the beginning of the lines, unless it calls a user like `sudo -Hu pleroma`; in this case, use `su <username> -s $SHELL -c 'command'` instead.

### Required packages

* `postgresql` (9,6+, CentOS 7 comes with 9.2, we will install version 11 in this guide)
* `elixir` (1.5+)
* `erlang`
* `erlang-parsetools`
* `erlang-xmerl`
* `git`
* Development Tools

#### Optional packages used in this guide

* `nginx` (preferred, example configs for other reverse proxies can be found in the repo)
* `certbot` (or any other ACME client for Let’s Encrypt certificates)

### Prepare the system

* First update the system, if not already done:

```shell
sudo yum update
```

* Install some of the above mentioned programs:

```shell
sudo yum install wget git unzip
```

* Install development tools:

```shell
sudo yum group install "Development Tools"
```

### Install Elixir and Erlang

* Add the EPEL repo:

```shell
sudo yum install epel-release
sudo yum -y update
```

* Install Erlang repository:

```shell
wget -P /tmp/ https://packages.erlang-solutions.com/erlang-solutions-1.0-1.noarch.rpm
sudo rpm -Uvh erlang-solutions-1.0-1.noarch.rpm
```

* Install Erlang:

```shell
sudo yum install erlang erlang-parsetools erlang-xmerl
```

* Download [latest Elixir release from Github](https://github.com/elixir-lang/elixir/releases/tag/v1.8.1) (Example for the newest version at the time when this manual was written)

```shell
wget -P /tmp/ https://github.com/elixir-lang/elixir/releases/download/v1.8.1/Precompiled.zip
```

* Create folder where you want to install Elixir, we’ll use:

```shell
sudo mkdir -p /opt/elixir
```

* Unzip downloaded file there:

```shell
sudo unzip /tmp/Precompiled.zip -d /opt/elixir
```

* Create symlinks for the pre-compiled binaries:

```shell
for e in elixir elixirc iex mix; do sudo ln -s /opt/elixir/bin/${e} /usr/local/bin/${e}; done
```

### Install PostgreSQL

* Add the Postgresql repository:

```shell
sudo yum install https://download.postgresql.org/pub/repos/yum/11/redhat/rhel-7-x86_64/pgdg-centos11-11-2.noarch.rpm
```

* Install the Postgresql server:

```shell
sudo yum install postgresql11-server postgresql11-contrib
```

* Initialize database:

```shell
sudo /usr/pgsql-11/bin/postgresql-11-setup initdb
```

* Open configuration file `/var/lib/pgsql/11/data/pg_hba.conf` and change the following lines from:

```plain
# IPv4 local connections:
host    all             all             127.0.0.1/32            ident
# IPv6 local connections:
host    all             all             ::1/128                 ident
```

to

```plain
# IPv4 local connections:
host    all             all             127.0.0.1/32            md5
# IPv6 local connections:
host    all             all             ::1/128                 md5
```

* Enable and start postgresql server:

```shell
sudo systemctl enable --now postgresql-11.service
```

### Install PleromaBE

* Add a new system user for the Pleroma service:

```shell
sudo useradd -r -s /bin/false -m -d /var/lib/pleroma -U pleroma
```

**Note**: To execute a single command as the Pleroma system user, use `sudo -Hu pleroma command`. You can also switch to a shell by using `sudo -Hu pleroma $SHELL`. If you don’t have and want `sudo` on your system, you can use `su` as root user (UID 0) for a single command by using `su -l pleroma -s $SHELL -c 'command'` and `su -l pleroma -s $SHELL` for starting a shell.

* Git clone the PleromaBE repository and make the Pleroma user the owner of the directory:

```shell
sudo mkdir -p /opt/pleroma
sudo chown -R pleroma:pleroma /opt/pleroma
sudo -Hu pleroma git clone -b stable https://git.pleroma.social/pleroma/pleroma /opt/pleroma
```

* Change to the new directory:

```shell
cd /opt/pleroma
```

* Install the dependencies for Pleroma and answer with `yes` if it asks you to install `Hex`:

```shell
sudo -Hu pleroma mix deps.get
```

* Generate the configuration: `sudo -Hu pleroma mix pleroma.instance gen`
  * Answer with `yes` if it asks you to install `rebar3`.
  * This may take some time, because parts of pleroma get compiled first.
  * After that it will ask you a few questions about your instance and generates a configuration file in `config/generated_config.exs`.

* Check the configuration and if all looks right, rename it, so Pleroma will load it (`prod.secret.exs` for productive instance, `dev.secret.exs` for development instances):

```shell
mv config/{generated_config.exs,prod.secret.exs}
```

* The previous command creates also the file `config/setup_db.psql`, with which you can create the database:

```shell
sudo -Hu postgres psql -f config/setup_db.psql
```

* Now run the database migration:

```shell
sudo -Hu pleroma MIX_ENV=prod mix ecto.migrate
```

* Now you can start Pleroma already

```shell
sudo -Hu pleroma MIX_ENV=prod mix phx.server
```

### Finalize installation

If you want to open your newly installed instance to the world, you should run nginx or some other webserver/proxy in front of Pleroma and you should consider to create a systemd service file for Pleroma.

#### Nginx

* Install nginx, if not already done:

```shell
sudo yum install nginx
```

* Setup your SSL cert, using your method of choice or certbot. If using certbot, first install it:

```shell
sudo yum install certbot-nginx
```

and then set it up:

```shell
sudo mkdir -p /var/lib/letsencrypt/
sudo certbot certonly --email <your@emailaddress> -d <yourdomain> --standalone
```

If that doesn’t work, make sure, that nginx is not already running. If it still doesn’t work, try setting up nginx first (change ssl “on” to “off” and try again).

---

* Copy the example nginx configuration to the nginx folder

```shell
sudo cp /opt/pleroma/installation/pleroma.nginx /etc/nginx/conf.d/pleroma.conf
```

* Before starting nginx edit the configuration and change it to your needs (e.g. change servername, change cert paths)
* Enable and start nginx:

```shell
sudo systemctl enable --now nginx
```

If you need to renew the certificate in the future, uncomment the relevant location block in the nginx config and run:

```shell
sudo certbot certonly --email <your@emailaddress> -d <yourdomain> --webroot -w /var/lib/letsencrypt/
```

#### Other webserver/proxies

You can find example configurations for them in `/opt/pleroma/installation/`.

#### Systemd service

* Copy example service file

```shell
sudo cp /opt/pleroma/installation/pleroma.service /etc/systemd/system/pleroma.service
```

* Edit the service file and make sure that all paths fit your installation
* Enable and start `pleroma.service`:

```shell
sudo systemctl enable --now pleroma.service
```

#### Create your first user

If your instance is up and running, you can create your first user with administrative rights with the following task:

```shell
sudo -Hu pleroma MIX_ENV=prod mix pleroma.user new <username> <your@emailaddress> --admin
```

#### Further reading

* [Backup your instance](../administration/backup.md)
* [Hardening your instance](../configuration/hardening.md)
* [How to activate mediaproxy](../configuration/howto_mediaproxy.md)
* [Updating your instance](../administration/updating.md)

## Questions

Questions about the installation or didn’t it work as it should be, ask in [#pleroma:matrix.org](https://matrix.heldscal.la/#/room/#freenode_#pleroma:matrix.org) or IRC Channel **#pleroma** on **Freenode**.