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In this posting you will be learning how to install Cacti on Google Cloud Platform using RockyLinux 8.

Addition Information

Step 1 – Swap Space

We will use the e2-micro instance with 0.25-2 vCPU ( 1 shared core) and 1 GB of RAM for this installation. Due to this limited memory, we are going to add some swap space to this system:

sudo fallocate -l 1G /swapfile 
sudo mkswap /swapfile 
sudo chmod 0600 /swapfile 
sudo swapon /swapfile

This will create a 1GB swapfile in the root directory. For it to be enabled during boot, we add a new statement to the /etc/fstab file:

sudo echo "/swapfile none swap defaults 0 0" >> /etc/fstab

Step 2 – Prerequisites

First, we must install some of the software packages needed for Cacti to run correctly. Using a minimal installation, we need to install the following repositories and packages

  • epel and remi repository
  • rrdtool
  • Apache
  • MariaDB
  • PHP and modules
  • gcc, net-snmp, and dev packages for spine installation

To use python for scripting purposes ( or ansible), we are also going to install it as well.

Let’s proceed with the package installation on our RockyLinux 8 system. So, we will enable the required EPEL ad REMI repositories:

sudo dnf install -y epel-release
sudo dnf install -y dnf-utils http://rpms.remirepo.net/enterprise/remi-release-8.rpm
sudo dnf -y module reset php
sudo dnf -y module enable php:remi-8.0
sudo dnf config-manager --set-enabled powertools

Now we can proceed with installing the packages:

dnf -y install mariadb-server php php-mysqlnd php-cli net-snmp-utils rrdtool gcc mariadb-devel 
dnf -y install net-snmp-devel autoconf automake libtool dos2unix wget php-posix php-ldap php-mbstring php-gd 
dnf -y install php-gmp php-zip php-json php-xml php-gettext php-curl php-intl help2man
sudo dnf -y install net-snmp net-snmp-devel net-snmp-utils

Now let’s install git and python, and also make sure we have the setuptool-rust installed in case we want to run ansible. Lastly, we also install some tools to manage SELinux:

sudo dnf -y install git python3-pip python3-devel python3-dnf
sudo dnf -y install policycoreutils-gui
sudo pip3 install setuptools-rust 
sudo pip3 install --upgrade pip

To have all packages up-to-date, let’s do a quick upgrade on our system as well:

sudo dnf -y upgrade

The above completes the specifics for the install Cacti on Google Cloud. Most of the tasks below are also valid for a CentOS7/RHEL7 installation.

In the next step, we will make sure that our webserver and the database are automatically starting up after a reboot. To do this, use the following commands to enable these:

sudo systemctl enable httpd.service
sudo systemctl enable mariadb.service
sudo systemctl restart mariadb.service

Now that we have the database server started, we need to populate it with the timezone data:

# Create the timezone data and import it into the mysqldatabase
sudo mysql_tzinfo_to_sql /usr/share/zoneinfo > /tmp/mysql_timezone.sql
sudo mysql mysql < /tmp/mysql_timezone.sql

Next, we need to change some settings for the MariaDB server. These will ensure that spine and Cacti are utilizing the database connection optimally. The following settings are for a 1GB memory system.

Don’t worry; Cacti will provide you with some recommended settings for your system during the installation process.

So, let’s edit the /etc/my.cnf.d/mariadb-server.cnf file and add the following lines to the [mysqld] section:

max_heap_table_size=90M
max_allowed_packet=16M
tmp_table_size=6M
join_buffer_size=6M
innodb_file_per_table=ON
innodb_buffer_pool_instances=3
innodb_buffer_pool_size=256M
innodb_doublewrite=OFF
innodb_lock_wait_timeout=50
innodb_flush_log_at_trx_commit=2
max_connections=50
character_set_server=utf8mb4
character_set_client=utf8mb4
collation_server=utf8mb4_unicode_ci
default-time-zone='Europe/Berlin'
innodb_flush_log_at_timeout=3
innodb_read_io_threads=32
innodb_write_io_threads=16
innodb_io_capacity=5000
innodb_io_capacity_max=10000
innodb_file_format=Barracuda
innodb_large_prefix=1

Make sure to adapt the default-time-zone to your requirements

Next, we need to restart the web server as well as the Maria DB service to continue the installation:

systemctl restart httpd.service
systemctl restart mariadb.service

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Step 3 – Cacti Files

Let’s now move to the actual installation of Cacti. First, we need to download and extract it. As of this writing, the current Cacti Version is 1.2.22.

cd /var/www/html
wget http://www.cacti.net/downloads/cacti-latest.tar.gz
tar -xzvf cacti-latest.tar.gz

Let’s now rename the cacti directory:

mv cacti-1.2.27 cacti

Step 4 – File permissions

We also need to make sure that the ownership of the required cacti directory is set correctly:

chown -R apache.apache /var/www/html/cacti/rra /var/www/html/cacti/log

Step 5 – Cacti Database

Now that we have extracted the cacti files, we can prepare the database for the final installation step. Your first step should be securing the MySQL database. The following command will help you with this task on a CentOS system. Make sure to select a strong password for root, e.g., MyN3wpassw0rd

/usr/bin/mysql_secure_installation

Let’s create a new database and assign a unique user to it:

# Create the Cacti database and populate it with the default data
mysqladmin -u root -p create cacti
mysql -p cacti < /var/www/html/cacti/cacti.sql
mysql -u root -p

With the last command, you should see a MySQL prompt where you can enter MySQL commands. Here we are going to create a unique cacti user. That user only needs to be able to connect from the local system and should also have a strong password. Enter the following commands and make sure to replace the password:

GRANT SELECT ON mysql.time_zone_name TO cactiuser@localhost IDENTIFIED BY 'MyV3ryStr0ngPassword';
GRANT ALL ON cacti.* TO cactiuser@localhost IDENTIFIED BY 'MyV3ryStr0ngPassword';
flush privileges;
exit

We now have the cacti files and the cacti database setup. The last step before moving to the web-based installer is setting the database credentials within the Cacti config file:

cd /var/www/html/cacti/include/
vi config.php

Change the $database_ lines to fit your new settings:

$database_type = "mysql";
$database_default = "cacti";
$database_hostname = "localhost";
$database_username = "cactiuser";
$database_password = "MyV3ryStr0ngPassword";
$database_port = "3306";
$database_ssl = false;

Depending on your installation, you should also uncomment the following line. In our example, we have to make sure the next line is there:

$url_path = "/cacti/";

Step 6 – Adding firewall rules

The following settings will enable the firewall and add access rules to HTTP and HTTPS from outside:

systemctl enable firewalld
systemctl start firewalld
firewall-cmd --permanent --zone=public --add-service=https 
firewall-cmd --permanent --zone=public --add-service=http 
firewall-cmd --reload

Step 7- Important PHP Settings

The default PHP installation usually has not configured the correct timezone or PHP error reporting. While not required to run Cacti, it’s highly recommended to enable error reporting to Syslog for troubleshooting issues with plugins or other scripts.

The following lines need to be enabled/configured in your /etc/php.ini file:

; Defines the default timezone used by the date functions
; http://php.net/date.timezone
date.timezone = Europe/Berlin

and

; Log errors to syslog (Event Log on NT, not valid in Windows 95).
error_log = syslog

We also increase the memory limit and max execution time:

memory_limit = 400M
max_execution_time = 60

We now restart the HTTP and PHP-FPM services so the changes become active

systemctl restart httpd.service
systemctl restart php-fpm

Step 8 – Set SELinux Context for http directory

SELinux interferes with the installation, so let’s disable it. Nevertheless, we will prepare the HTML directory to have the correct SELinux context :

sudo setenforce 0
sudo chcon -R -t httpd_sys_rw_content_t /var/www/html
sudo semanage fcontext -a -t httpd_sys_rw_content_t "/var/www/html(/.*)?"

Step 8 – Running the Web-based installer

Let’s move on to the web-based installer.

TBD

Login with admin/admin, and you’re ready to go!

Please go to “Console -> System Utilities” and click on “Rebuild Poller Cache” after the first login!

Step 9 – Installing Spine

Now let us look into installing Spine as a replacement of the cmd.php poller.

The following task will download, compile and configure the spine poller:

## Install Spine
cd /tmp
wget https://files.cacti.net/spine/cacti-spine-latest.tar.gz
tar -xzvf cacti-spine-latest.tar.gz
cd cacti-spine-1.2.27
sudo ./bootstrap
sudo ./configure
sudo make
sudo make install
sudo chown root:root /usr/local/spine/bin/spine
sudo chmod +s /usr/local/spine/bin/spine
sudo cp /usr/local/spine/etc/spine.conf.dist /usr/local/spine/etc/spine.conf
sudo sed -i "s/DB_Pass       cactiuser/DB_Pass       MyV3ryStr0ngPassword/ig" /usr/local/spine/etc/spine.conf

 

Step 10 – Cron Job

Cacti uses cron (scheduled task) to execute its polling process. It’s always a good idea to run this under a different user than root.

Let’s now add a new cron entry to your system for a 1-minute polling interval using the following command:

echo "*/1 * * * * apache php /var/www/html/cacti/poller.php &>/dev/null" >> /etc/cron.d/cacti

Need Commercial Support on how to install Cacti on Google Cloud Platform?

Urban-Software.de offers commercial Cacti support for Cacti itself and several plugins ( e.g., Thold ).
There’s going to be an on-demand solution in the future. You can contact us for more details using the contact form.

If you require free support, please visit the cacti forum!