About load balancers

Access Gatewayis often deployed in a high availability scenario using a load balancer.

Typical Access Gateway Load Balancer Architecture

Topics

 

Load balancer configuration

Load balancers:

  • Sticky sessions or session affinity: Any load balancer used with Access Gateway must support and enable session affinity or sticky sessions. Session affinity refers to the feature of most load balancing solutions wherein the second and subsequent requests for a particular session are routed to the same Access Gateway node.
  • Load balancer strategy: The preferred strategy for an Access Gateway load balancer is round-robin or weighted round-robin.
Note

Note

When configuring a load balancer, the Access Gateway admin node is typically not included as part of the worker pool.

Node Health Check

 

Load balancers must be able to determine if Access Gateway cluster members are healthy.
To perform a health check send an HTTP request with the following:

Protocol HTTPS
Request GET
IP IP Address of each worker node
With header Host: Your gateway's host

For example:

curl -X GET -v -k https://10.0.0.225/status -H 'Host:gw.yourhost.com'
Where:

  • -X GET - Make a get request
  • -v - Verbose (not require for production)
  • -k - Insecure
  • -H 'Host:gw.{yourgateway.tld}

This returns a status of 200 on success and 400 or timeout on error.

To determine the value for the Host header variable:

  1. Sign in to the Access Gateway Admin UI console.
  2. Select Settings.
  3. Select the Access Gateway.
  4. In the System Configuration section, examine the value of the Access Gateway Hostname field.
    Access Gateway Hostname

Cluster upgrades and load balancers

To upgrade Access Gateway:

  1. Backup the configuration. See About backup and restore
  2. For the admin instance, secure shell (ssh oag-mgmt@gw.gateway.tld) into the Command Line Management Console.
  3. Follow the process for upgrading the Access Gateway appliance. See Upgrade Access Gateway nodes .
  4. For each worker node in the Access Gateway high availability cluster.
    1. Take the worker node out of the load balancer rotation.
    2. Update the worker node.
    3. Return the worker node to the load balancer rotation.