Load balancer configuration

The solution supports a number of load balancer configuration options:

• Use the playbooks to configure two load balancers, for highly available, production deployments.
• Use the playbooks to configure a single load balancer, useful for proof of concept deployments.

When deploying two load balancers, a floating IP is deployed and managed by keepalived. Your settings for rancher.hostname and rancher.url variables should resolve to the address you chose for this floating IP. If you configure a single load balancer, you don't need a floating IP and the rancher.hostname should resolve to the IP of the standalone load balancer.

The admin_template is used when provisioning the load balancer VMs.

Deploying two load balancers

With this option, two load balancers are deployed in an active-active configuration to provide highly-available access.

Two virtual machines are configured in the hosts inventory file. You configure one of the VMs as the preferred VM for hosting the internal VIP for the Rancher API, by adding api_int_preferred= to the definition.

A sample configuration for deploying two load balancers is shown below. This extract from an Ansible hosts inventory file shows the entries defining the nodes used for the load balancers:

[loadbalancer]
hpe-lb1              ansible_host=10.15.152.11 api_int_preferred=true
hpe-lb2              ansible_host=10.15.152.12

This extract from the configuration file group_vars/all/vars.yml shows the configuration required for the two load balancer scenario:

rancher_subnet: 10.15.152.0/24

rancher:
  url: https://rancher.hpe.org
  hostname: rancher.hpe.org


loadbalancers:
  backend:
    vip: 10.15.152.9/24
    vrrp_router_id: 51
    nginx_max_fails: 1
    nginx_fail_timeout: 10s
    nginx_proxy_timeout: 10m
    nginx_proxy_connect_timeout: 60s

The vrrp_router_id is used to differentiate between multiple deployments on the same networking infrastructure, for example, in proof of concepts. If you have multiple deployments, ensure that each deployment uses unique VRRP router IDs.

You must configure DNS to resolve the value of the rancher.hostname (in this case rancher.hpe.org) to the value of the loadbalancers.backend.vip variable (in this case, 10.15.152.9). Note that this VIP address must be in the Rancher subnet and outside the DHCP range, like any other IP address in the hosts inventory.

Deploying one load balancer

If you do not require high availability, you can deploy a single load balancer to reduce complexity and resource requirements. In this instance, you only specify a single entry in the [loadbalancer] group in your hosts file.

[loadbalancer]
hpe-lb1              ansible_host=10.15.152.11

Simply comment out the vip and vrrp_router_id variables in the loadbalancers.backend structure. You must configure DNS to resolve the value of the rancher.hostname (in this case rancher.hpe.org) to the value of the IP addess of the single load balancer VM (in this case 10.15.152.11).

rancher_subnet: 10.15.152.0/24

rancher:
  url: https://rancher.hpe.org
  hostname: rancher.hpe.org

loadbalancers:
  backend:
#    vip: 10.15.152.9/24
#    vrrp_router_id: 51
    nginx_max_fails: 1
    nginx_fail_timeout: 10s
    nginx_proxy_timeout: 10m
    nginx_proxy_connect_timeout: 60s