NOTE: What follows is a very rough list of commands.  This works on a fresh install of CentOS 6.4 and CentOS 7.

NOTE: These instructions assume you are the root user.  If you are not, prepend `sudo` to all shell commands (the ones that aren't at `mysql>` prompts) or temporarily become a user with root privileges with `sudo -s`.

### On the DB Server ###

This host is where the MySQL database runs.  It could be the same machine as your network management server (this is the most common initial deployment scenario).

> ** Whilst we are working on ensuring LibreNMS is compatible with MySQL strict mode, for now, please disable this after mysql is installed.

You are free to choose between using MySQL or MariaDB:

**MySQL** (NOTE: In CentOS 7 there is only mariadb in official repo)
```bash
yum install net-snmp mysql-server mysql-client
chkconfig mysqld on
service mysqld start
```

**MariaDB**
```bash
yum install net-snmp mariadb-server mariadb-client
chkconfig mariadb on (systemctl enable mariadb on CentOS 7)
service mariadb start (systemctl start mariadb on CentOS 7)
```

Now continue with the installation:

```bash
chkconfig snmpd on (systemctl enable snmpd on CentOS 7)
service snmpd start (systemctl start snmpd on CentOS 7)
mysql_secure_installation
mysql -uroot -p
```

Enter the MySQL/MariaDB root password to enter the command-line interface.

Create database.

```sql
CREATE DATABASE librenms;
GRANT ALL PRIVILEGES ON librenms.*
  TO 'librenms'@'<ip>'
  IDENTIFIED BY '<password>'
;
FLUSH PRIVILEGES;
exit
```

Replace `<ip>` above with the IP of the server running LibreNMS.  If your database is on the same server as LibreNMS, you can just use `localhost` as the IP address.

If you are deploying a separate database server, you need to change the `bind-address`.  If your MySQL database resides on the same server as LibreNMS, you should skip this step.

    vim /etc/my.cnf

Add the following line:

    bind-address = <ip>

Change `<ip>` to the IP address that your MySQL server should listen on.  Restart MySQL:

If you see a line that starts `sql-mode` then change this to `sql-mode=""`.

    service mysqld restart

### On the NMS ###

Install necessary software.  The packages listed below are an all-inclusive list of packages that were necessary on a clean install of CentOS 6.4.  It also requires the EPEL repository.

Note if not using HTTPd (Apache): RHEL requires `httpd` to be installed regardless of of `nginx`'s (or any other web-server's) presence.

    yum install epel-release
(CentOS 6)    yum install php php-cli php-gd php-mysql php-snmp php-pear php-curl httpd net-snmp graphviz graphviz-php mysql ImageMagick jwhois nmap mtr rrdtool MySQL-python net-snmp-utils vixie-cron php-mcrypt fping git
(CentOS 7)    yum install php php-cli php-gd php-mysql php-snmp php-pear php-curl httpd net-snmp graphviz graphviz-php mariadb ImageMagick jwhois nmap mtr rrdtool MySQL-python net-snmp-utils vixie-cron php-mcrypt fping git
    pear install Net_IPv4-1.3.4
    pear install Net_IPv6-1.2.2b2

### Adding the librenms-user for Apache ###
```bash
    useradd librenms -d /opt/librenms -M -r
    usermod -a -G librenms apache
```

### Adding the librenms-user for Nginx ###
```bash
    useradd librenms -d /opt/librenms -M -r
    usermod -a -G librenms nginx
```

### Using HTTPd (Apache2) ###

Set `httpd` to start on system boot.

    chkconfig --levels 235 httpd on (systemctl enable httpd on CentOS 7)

Next, add the following to `/etc/httpd/conf.d/librenms.conf`

```apache
<VirtualHost *:80>
  DocumentRoot /opt/librenms/html/
  ServerName  librenms.example.com
  CustomLog /opt/librenms/logs/access_log combined
  ErrorLog /opt/librenms/logs/error_log
  AllowEncodedSlashes On
  <Directory "/opt/librenms/html/">
    AllowOverride All
    Options FollowSymLinks MultiViews
  </Directory>
</VirtualHost>
```

__Notes:__  
If you are running Apache 2.2.18 or higher then change `AllowEncodedSlashes` to `NoDecode` and append `Require all granted` underneath `Options FollowSymLinks MultiViews`.  
If the file `/etc/httpd/conf.d/welcome.conf` exists, you might want to remove that as well unless you're familiar with [Name-based Virtual Hosts](https://httpd.apache.org/docs/2.2/vhosts/name-based.html)

### Using Nginx and PHP-FPM ###

Install necessary extra software and let it start on system boot.

    yum install nginx php-fpm
    chkconfig nginx on (systemctl enable nginx on CentOS 7)
    chkconfig php-fpm on (systemctl enable php-fpm on CentOS 7)

Modify permissions and configuration for `php-fpm` to use nginx credentials.

    mkdir /var/lib/php/session
    chown root:nginx /var/lib/php -R
    vi /etc/php-fpm.d/www.conf      # At line #12: Change `listen` to `/var/run/php5-fpm.sock`
                                    # At line #39-41: Change the `user` and `group` to `nginx`

Add configuration for `nginx` at `/etc/nginx/conf.d/librenms.conf` with the following content:

```nginx
server {
 listen      80;
 server_name librenms.example.com;
 root        /opt/librenms/html;
 index       index.php;
 access_log  /opt/librenms/logs/access_log;
 error_log   /opt/librenms/logs/error_log;
 location / {
  try_files $uri $uri/ @librenms;
 }
 location ~ \.php {
  include fastcgi.conf;
  fastcgi_split_path_info ^(.+\.php)(/.+)$;
  fastcgi_pass unix:/var/run/php5-fpm.sock;
 }
 location ~ /\.ht {
  deny all;
 }
 location @librenms {
  rewrite ^api/v0(.*)$ /api_v0.php/$1 last;
  rewrite ^(.+)$ /index.php/$1 last;
 }
}
```

### Cloning ###

You can clone the repository via HTTPS or SSH.  In either case, you need to ensure the appropriate port (443 for HTTPS, 22 for SSH) is open in the outbound direction for your server.

    cd /opt
    git clone https://github.com/librenms/librenms.git librenms
    cd /opt/librenms

At this stage you can either launch the web installer by going to http://IP/install.php, follow the on-screen instructions then skip to the 'Web Interface' section further down. Alternatively if you want
to continue the setup manually then just keep following these instructions.

    cp config.php.default config.php
    vim config.php

NOTE: The recommended method of cloning a git repository is HTTPS.  If you would like to clone via SSH instead, use the command `git clone git@github.com:librenms/librenms.git librenms` instead.

Change the values to the right of the equal sign for lines beginning with `$config[db_]` to match your database information as setup above.

Change the value of `$config['snmp']['community']` from `public` to whatever your read-only SNMP community is.  If you have multiple communities, set it to the most common.

Add the following line to the end of `config.php`:

    $config['fping'] = "/usr/sbin/fping";

** Be sure you have no characters (including whitespace like: newlines, spaces, tabs, etc) outside of the `<?php?>` blocks. Your graphs will break otherwise. **

### Initialise the database ###

Initiate the follow database with the following command:

    php build-base.php

### Create admin user ###

Create the admin user - priv should be 10

    php adduser.php <name> <pass> 10 <email>

Substitute your desired username, password and email address--and leave the angled brackets off.

### Web Interface ###

To prepare the web interface (and adding devices shortly), you'll need to create and chown a directory as well as create an Apache vhost.

First, create and chown the `rrd` directory and create the `logs` directory

```bash
    mkdir rrd logs
    chown -R librenms:librenms /opt/librenms
    chmod 775 rrd

    # For HTTPd (Apache):
    chown apache:apache logs

    # For Nginx:
    chown nginx:nginx logs
```

> If you're planing on running rrdcached, make sure that the path is also chmod'ed to 775 and chown'ed to librenms:librenms.

**SELinux**
> if you're using SELinux you need to allow nginx to write into logs directory.
> semanage tool is a part of policycoreutils-python, so if don't have it, you can install it
> Please note that running LibreNMS with SELinux is still experimental and we cannot guarantee that everything will be working fine for now.

```bash
    yum install policycoreutils-python
```

```bash
    semanage fcontext -a -t httpd_sys_content_t '/opt/librenms/logs(/.*)?'
    semanage fcontext -a -t httpd_sys_rw_content_t '/opt/librenms/logs(/.*)?'
    restorecon -RFvv /opt/librenms/logs/
```

Start the web-server:

    # For HTTPd (Apache):
    service httpd restart (systemctl restart httpd on CentOS 7)

    # For Nginx:
    service nginx restart (systemctl restart nginx on CentOS 7)

### Add localhost ###

    php addhost.php localhost public v2c

This assumes you haven't made community changes--if you have, replace `public` with your community.  It also assumes SNMP v2c.  If you're using v3, there are additional steps (NOTE: instructions for SNMPv3 to come).

Discover localhost:

    php discovery.php -h all

### Create cronjob ###

The polling method used by LibreNMS is `poller-wrapper.py`, which was placed in
the public domain by its author.  By default, the LibreNMS cronjob runs `poller-
wrapper.py` with 16 threads.  The current LibreNMS recommendation is to use 4 th
reads per core.  The default if no thread count is `16 threads`.

If the thread count needs to be changed, you can do so by editing the cron file (`/etc/cron.d/librenms`).
 Just add a number after `poller-wrapper.py`, as in the below example:

    /opt/librenms/poller-wrapper.py 12 >> /dev/null 2>&1

Create the cronjob

    cp librenms.nonroot.cron /etc/cron.d/librenms

### Daily Updates ###

LibreNMS performs daily updates by default.  At 00:15 system time every day, a `git pull --no-edit --quiet` is performed.  You can override this default by edit
ing your `config.php` file.  Remove the comment (the `#` mark) on the line:

    #$config['update'] = 0;

so that it looks like this:

    $config['update'] = 0;

### Install complete ###

Please allow for 2-3 runs of the poller-wrapper for data to start appearing in the WebUI.
If you don't see data after this, please refer to the [FAQ](http://docs.librenms.org/Support/FAQ/) for assistance.

That's it!  You now should be able to log in to http://librenms.example.com/.  Please note that we have not covered HTTPS setup in this example, so your LibreNMS install is not secure by default.  Please do not expose it to the public Internet unless you have configured HTTPS and taken appropriate web server hardening steps.

It would be great if you would consider opting into the stats system we have, please see [this page](http://docs.librenms.org/General/Callback-Stats-and-Privacy/) on what it is and how to enable it.