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Load Balancing & High Availability

What is Load Balancing​

What is High Availability?​

What technologies can we use for this?​

Keepalived​

Network UPS Tools, or 'Nut', is a Open Source UPS monitoring tool, that has the ability to interface with a wide variety of different UPS & power supply brands, across several different operating system types. It is hardware and OS agnostic in nature, which makes it great to deploy on network/s that have a variety of different OS's.

Why Keepalived?​

Pre-Req's​

  1. Two servers

Overview​

The idea here is that we will deploy NUT server on a Raspberry Pi Zero W2, with Ethernet HAT, and have that act as the NUT server, feeding the monitoring/metrics to other devices, such as virtualization hosts.

Master Server​

Install the apt package needed for keepalived. sudo apt install keepalived

Get the name of the local ethernet adaptor​

ifconfig Look for the entry that shows your current IP, usually eth0 or enps0 or similar.

Create the config file​

Create the follow file and contents with your text editor of choice.
Example - sudo nano /etc/keepalived/keepalived.conf

vrrp_instance VI_1 {
  state MASTER
  interface eth0
  virtual_router_id 51
  priority 100
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass yourpassword
  }
  virtual_ipaddress {
    192.168.200.253/24
  }
}

In this file -

  1. Replace the interface name with the one you got from the previous step.
  2. Replace the virtual ip address with the IP you want to be shared between the systems.
  3. Replace the auth_pass password with a password of your choosing.

Restart the service​

Now we need to restart keepalived.
sudo service keepalived restart

Check the config works​

Using the command sudo service keepalived status

Secondary Server​

Install the apt package needed for keepalived. sudo apt install keepalived

Testing​

Conclusion​

Further Reading​

HAProxy​

Network UPS Tools, or 'Nut', is a Open Source UPS monitoring tool, that has the ability to interface with a wide variety of different UPS & power supply brands, across several different operating system types. It is hardware and OS agnostic in nature, which makes it great to deploy on network/s that have a variety of different OS's.

Why HAProxy?​

Pre-Req's​

  1. A container host

Overview​

The idea here is that we will deploy NUT server on a Raspberry Pi Zero W2, with Ethernet HAT, and have that act as the NUT server, feeding the monitoring/metrics to other devices, such as virtualization hosts.

Deploy the container​

Next, we need to deploy the HAProxy container. Using your container manager of choice (or GUI), deploy the following docker-compose -

note

This assumes you have used other guides on this site, with the usage of a proxynet, etc.
If you havn't, you'll need to adjust as needed.

version: '1'
services:
# haproxy-proxmox
  haproxy-proxmox:
    container_name: haproxy-proxmox
    hostname: haproxy-proxmox
    image: haproxytech/haproxy-ubuntu
    restart: unless-stopped
    networks:
        - proxynet
    volumes:
      - appdata:/usr/local/etc/haproxy
      
# Networks
networks:
  proxynet:
    name: proxynet
    
# Volumes
volumes:
  appdata:
    driver: local

sudo apt install keepalived

Create the config file​

ifconfig Look for the entry that shows your current IP, usually eth0 or enps0 or similar.

sudo nano /etc/keepalived/keepalived.conf

XXX

In this file -

  1. Replace the interface name with the one you got from the previous step.
  2. Replace the virtual ip address with the IP you want to be shared between the systems.
  3. Replace the auth_pass password with a password of your choosing.

Restart the container​

Now we need to restart keepalived.
sudo service keepalived restart

Check the config works​

Using the command sudo service keepalived status

Testing​

Conclusion​

Further Reading​