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.

**CentOS 6**:
You are free to choose between using MySQL or MariaDB:

**MySQL**
```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
service mariadb start
```

**CentOS 7**
(NOTE: In CentOS 7 there is only mariadb in official repo)

**MariaDB**
```bash
yum install net-snmp mariadb-server mariadb-client
systemctl enable mariadb
systemctl start mariadb
```

Now continue with the installation:

**CentOS 6**
```bash
chkconfig snmpd on
service snmpd start
mysql_secure_installation
mysql -uroot -p
```

**CentOS 7**
```bash
systemctl enable snmpd
systemctl start snmpd
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, use `localhost` as the IP address.

Edit the mysql/mariadb configuration file:
```bash
vim /etc/my.cnf
```

Add the following line:

    innodb_file_per_table=1

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

    bind-address = <ip>

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

Save, and restart MySQL/MariaDB to apply your changes:

    service mysqld restart

or

    service mariadb 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 or 7.  It also requires the EPEL repository. Net_IPv6 is required even if your network environment does not support IPv6.

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

**CentOS 6**
```bash
    yum install epel-release
    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
    pear install Net_IPv4-1.3.4
    pear install Net_IPv6-1.2.2b2
```

**CentOS 7**
```bash
    yum install epel-release
    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 cronie php-mcrypt fping git
    pear install Net_IPv4-1.3.4
    pear install Net_IPv6-1.2.2b2
```
### Configure SNMPD on localhost ###
Edit `/etc/snmp/snmpd.conf` to enable self-polling.  An absolute minimal config for snmpd is:

    rocommunity public 127.0.0.1

You may either edit the default configuration file to your liking, or backup the default config file and replace it entirely with your own. To apply your changes, run `service snmpd restart` for Centos 6, or `systemctl restart snmpd` for Centos 7 (w/ systemd). If you have deployed a separate database server, you will likely want to configure snmpd on that host as well.


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

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

### Using HTTPd (Apache2) ###

Set `httpd` to start on system boot.

**CentOS 6: **
```bash
chkconfig --levels 235 httpd on
```

**CentOS 7 (with Systemd): **
```bash
systemctl enable httpd
```

In `/etc/php.ini`, ensure `date.timezone` is set to your preferred time zone.  See http://php.net/manual/en/timezones.php for a list of supported timezones.  Valid
examples are: "America/New York", "Australia/Brisbane", "Etc/UTC".
Please also ensure that `allow_url_fopen` is enabled. Other functions needed for LibreNMS include `exec,passthru,shell_exec,escapeshellarg,escapeshellcmd,proc_close,proc_open,popen`.

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

If you are running Apache below version 2.2.18:
```apache
<VirtualHost *:80>
  DocumentRoot /var/www/librenms/html/
  ServerName  librenms.example.com
  CustomLog /var/www/librenms/logs/access_log combined
  ErrorLog /var/www/librenms/logs/error_log
  AllowEncodedSlashes On
  <Directory "/var/www/librenms/html/">
    AllowOverride All
    Options FollowSymLinks MultiViews
  </Directory>
</VirtualHost>
```


If you are running Apache 2.2.18 or higher (current version in Centos 7 official repo):
```apache
<VirtualHost *:80>
  DocumentRoot /var/www/librenms/html/
  ServerName  librenms.example.com
  CustomLog /var/www/librenms/logs/access_log combined
  ErrorLog /var/www/librenms/logs/error_log
  AllowEncodedSlashes NoDecode
  <Directory "/var/www/librenms/html/">
    AllowOverride All
    Options FollowSymLinks MultiViews
    Require all granted
  </Directory>
</VirtualHost>
```
If the file `/etc/httpd/conf.d/welcome.conf` exists, you will 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). 
```bash
rn /etc/httpd/conf.d/welcome.conf /etc/httpd/conf.d/welcome.conf.bak
```

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

If you choose to run Nginx, you will need to install necessary extra software and let it start on system boot.

**CentOS 6**
```bash
    yum install nginx php-fpm
    chkconfig nginx on
    chkconfig php-fpm on
```

**CentOS 7**
```bash
    yum install nginx php-fpm
    systemctl enable nginx
    systemctl enable php-fpm
```

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

    mkdir /var/lib/php/session
    chown root:nginx /var/lib/php -R
    vim /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        /var/www/librenms/html;
 index       index.php;
 access_log  /var/www/librenms/logs/access_log;
 error_log   /var/www/librenms/logs/error_log;
 location / {
  try_files $uri $uri/ @librenms;
 }
 location ~ \.php {
  fastcgi_param PATH_INFO $fastcgi_path_info;
  include fastcgi.conf;
  fastcgi_split_path_info ^(.+\.php)(/.+)$;
  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.

```bash
    cd /opt
    git clone https://github.com/librenms/librenms.git librenms
    cd /var/www/librenms
```
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.

### Prepare the Web Interface ###

To prepare the web interface, 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 /var/www/librenms
    chmod 775 rrd
```

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 (in Centos 7 this is the defualt) you need to allow web server user 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 '/var/www/librenms/logs(/.*)?'
    semanage fcontext -a -t httpd_sys_rw_content_t '/var/www/librenms/logs(/.*)?'
    restorecon -RFvv /var/www/librenms/logs/
```

Set selinux to allow httpd to sendmail
```bash
    setsebool -P httpd_can_sendmail=1
```

### Start the web-server: ###

**CentOS 6**

    # For HTTPd (Apache):
    service httpd restart

    # For Nginx:
    service nginx restart

**CentOS 7**

    # For HTTPd (Apache):
    systemctl restart httpd

    # For Nginx:
    systemctl restart nginx

### Web Installer ###

At this stage you can launch the web installer by going to `http://IP/install.php` and follow the on-screen instructions. Alternatively if you want to continue the setup manually then perform the manual install steps. If you cannot reach the installer, stop here and solve that problem before proceeding. Afterwards, Add the following line to the end of `config.php`:

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

### Manual Install ###

You may skip this section if the web installer succeeded.

```bash
    cp config.php.default config.php
    vi config.php
```

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

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

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

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

Important: Be sure you have no characters (including whitespace like: newlines, spaces, tabs, etc) outside of the `<?php?>` blocks. Your graphs will break otherwise and there will be no error messages to indicate otherwise!

**Initialize 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.


### Validate your install ###
After performing the manual install or web install, be sure to run validate.php as root in the librenms directory:

    php validate.php

This will check your install to verify it is set up correctly.

### Add localhost ###

    php addhost.php localhost public v2c

Replace `public` to match what you set in `/etc/snmp/snmpd.conf`.  This command also assumes you are using 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 threads 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:

    /var/www/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 editing
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.
