PowerGSLB - PowerDNS Remote GSLB Backend

PowerGSLB is a simple DNS based Global Server Load Balancing (GSLB) solution.

Table of Contents

• PowerGSLB - PowerDNS Remote GSLB Backend
  • Table of Contents
  • Main features
  • Database diagram
  • Class diagram
  • Web based administration interface
  • Installation on CentOS 7
    • Setup PowerGSLB and PowerDNS
    • Setup MariaDB
    • Start services
    • Test PowerGSLB
    • Web based administration interface
  • Health checks
    • Mandatory parameters
    • Exec parameters
    • ICMP parameters
    • HTTP parameters
    • TCP parameters
  • Building PowerGSLB RPM packages
  • Using PowerGSLB Docker image
  • Building PowerGSLB Docker image
  • Using PowerGSLB LB Client

Main features

• Quick installation and setup
• Written in Python 2.7
• Built as PowerDNS Authoritative Server Remote Backend
• Web based administration interface using w2ui
• HTTPS support for the web server
• DNS GSLB configuration stored in a MySQL / MariaDB database
• Master-Slave DNS GSLB using native MySQL / MariaDB replication
• Multi-Master DNS GSLB using native MySQL / MariaDB Galera Cluster
• Modular architecture
• Multithreaded architecture
• Systemd status and watchdog support
• Extendable health checks:
  • ICMP ping
  • TCP connect
  • HTTP request
  • Arbitrary command execution
• Fallback if all the checks failed
• Weighted (priority) records
• Per record client IP / subnet persistence
• DNS GSLB views support
• All-in-one Docker image

Database diagram

Class diagram

Web based administration interface

Status grid

Advanced search

Add new record

More images

Installation on CentOS 7

Setup PowerGSLB and PowerDNS

yum -y install epel-release
yum -y update
yum -y install python2-pip

pip install pyping

VERSION=1.7.5
yum -y --setopt=tsflags= install \
    "https://github.com/kuuhaku86/powergslb/releases/download/$VERSION/powergslb-$VERSION-1.el7.noarch.rpm" \
    "https://github.com/kuuhaku86/powergslb/releases/download/$VERSION/powergslb-admin-$VERSION-1.el7.noarch.rpm" \
    "https://github.com/kuuhaku86/powergslb/releases/download/$VERSION/powergslb-pdns-$VERSION-1.el7.noarch.rpm"

sed -i 's/^password = .*/password = your-database-password-here/g' /etc/powergslb/powergslb.conf

cp /etc/pdns/pdns.conf /etc/pdns/pdns.conf~
cp "/usr/share/doc/powergslb-pdns-$VERSION/pdns/pdns.conf" /etc/pdns/pdns.conf

echo -e '#!/usr/bin/env python2.7\n' > /etc/powergslb/load-balancing-check
cat << EOF >> /etc/powergslb/load-balancing-check

import socket
import sys
import mysql.connector
import logging

ADDRESS = str(sys.argv[1])
PORT = int(sys.argv[2])
DB_ADDRESS = "127.0.0.1"
DB_PORT = 3306

operation = """
    UPDATE records
    SET weight = %s
    WHERE records.content_monitor_id = (
        SELECT contents_monitors.id 
        FROM contents_monitors
        JOIN monitors ON contents_monitors.monitor_id = monitors.id
        JOIN contents ON contents_monitors.content_id = contents.id
        WHERE monitors.monitor = "Load Balancing Check"
        AND contents.content = %s
        LIMIT 1
    )
"""

try: 
    logging.basicConfig(filename='/var/log/load-balancing.log', filemode='a', format='%(asctime)s - %(name)s - %(levelname)s - %(message)s')

    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    sock.connect((ADDRESS, PORT))

    data = sock.recv(1024)
    data = data.decode('UTF-8')
    data = int(float(data))

    connection = mysql.connector.connect(
        host=DB_ADDRESS,
        port=DB_PORT,
        user="powergslb",
        database="powergslb",
        password="your-database-password-here")

    cursor = connection.cursor()

    cursor.execute(operation, (data, ADDRESS, ))

    connection.commit()

    cursor.close()
except Exception:
    logging.exception("message")
EOF

sed -i "s/your-database-password-here/your-database-password-here/g" /etc/powergslb/load-balancing-check

chmod 777 /etc/powergslb/load-balancing-check

Setup MariaDB

yum -y install mariadb-server

sed -i '/\[mysqld\]/a bind-address=127.0.0.1\ncharacter_set_server=utf8' /etc/my.cnf.d/server.cnf

systemctl enable mariadb.service
systemctl start mariadb.service
systemctl status mariadb.service

mysql_secure_installation

VERSION=1.7.5
mysql -p << EOF
CREATE DATABASE powergslb;
GRANT ALL ON powergslb.* TO powergslb@localhost IDENTIFIED BY 'your-database-password-here';
USE powergslb;
source /usr/share/doc/powergslb-$VERSION/database/scheme.sql
source /usr/share/doc/powergslb-$VERSION/database/data.sql
EOF

Start services

systemctl enable powergslb.service pdns.service
systemctl start powergslb.service pdns.service
systemctl status powergslb.service pdns.service

Test PowerGSLB

yum -y install bind-utils

dig @127.0.0.1 example.com SOA
dig @127.0.0.1 example.com A
dig @127.0.0.1 example.com AAAA
dig @127.0.0.1 example.com ANY

Web based administration interface

Open URL https://SERVER/admin/.

• Default username: admin
• Default password: admin

Health checks

Health checks are configured in the "Monitors" sidebar section in JSON format.

Supported check types:

type	description
exec	arbitrary command execution
icmp	ICMP ping
http	HTTP request
tcp	TCP connect

Mandatory parameters

General parameters for all checks:

parameter	description
type	check type
interval	interval between checks
timeout	check timeout
fall	number of failed checks to disable record
rise	number of successful checks to enable record

Exec parameters

parameter	description
type	exec
args	command to execute and arguments

Example:

{"type": "exec", "args": ["/etc/powergslb/powergslb-check", "%(content)s"], "interval": 3, "timeout": 1, "fall": 3, "rise": 5}

ICMP parameters

parameter	description
type	icmp
ip	endpoint IP address

Example:

{"type": "icmp", "ip": "%(content)s", "interval": 3, "timeout": 1, "fall": 3, "rise": 5}

HTTP parameters

parameter	description
type	http
url	endpoint URL

Example:

{"type": "http", "url": "http://%(content)s/status", "interval": 3, "timeout": 1, "fall": 3, "rise": 5}

TCP parameters

parameter	description
type	tcp
ip	endpoint IP address
port	endpoint port number

Example:

{"type": "tcp", "ip": "%(content)s", "port": 80, "interval": 3, "timeout": 1, "fall": 3, "rise": 5}

Building PowerGSLB RPM packages

You should always create RPM packages in a clean environment and preferably on a separate machine!

Please read How to create an RPM package.

yum -y update
yum -y install @Development\ Tools

VERSION=1.7.5
curl "https://codeload.github.com/kuuhaku86/powergslb/tar.gz/$VERSION" -o "powergslb-$VERSION.tar.gz"
rpmbuild -tb --define "version $VERSION" "powergslb-$VERSION.tar.gz"

Upon successful completion you will have three packages

~/rpmbuild/RPMS/noarch/powergslb-$VERSION-1.el7.noarch.rpm
~/rpmbuild/RPMS/noarch/powergslb-admin-$VERSION-1.el7.noarch.rpm
~/rpmbuild/RPMS/noarch/powergslb-pdns-$VERSION-1.el7.noarch.rpm

Using PowerGSLB Docker image

For quick setup, you can pull all-in-one Docker image from docker.io.

VERSION=1.7.5

docker pull docker.io/kuuhaku86/powergslb:"$VERSION"

docker run -itd --name powergslb --hostname powergslb \
    -p 53:53/tcp -p 53:53/udp -p 443:443/tcp \
    --tmpfs /run --tmpfs /tmp -v /sys/fs/cgroup:/sys/fs/cgroup:ro \
    kuuhaku86/powergslb:"$VERSION"

docker inspect --format='{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' powergslb

docker exec -it powergslb bash

docker stop powergslb

For systemd to run in Docker container the following SELinux boolean should be enabled.

semanage boolean --modify --on container_manage_cgroup

Building PowerGSLB Docker image

To create an all-in-one Docker image.

VERSION=1.7.5

docker build -f docker/Dockerfile --build-arg VERSION="$VERSION" \
    --force-rm --no-cache -t powergslb:"$VERSION" https://github.com/kuuhaku86/powergslb.git

Using PowerGSLB LB Client

Run with docker

VERSION=1.7.5

docker run -itd --net=host -e INTERFACE=[Your Internet Interface] \
    -e BANDWITH_CAPACITY=[Your Internet Bandwith] -e CPU_PRIORITY=[Integer CPU Pirority] \
    -e MEMORY_PRIORITY=[Integer Memory Pirority] -e BANDWITH_PRIORITY=[Integer BANDWITH Pirority] \
    --name powergslb-lb-client \
    docker.io/kuuhaku86/powergslb-lb-client:"$VERSION"
  
# Use this for testing (Change 1G with memory that you want to be occupied)
stress -m 1 --vm-bytes 1G --vm-keep