High Availability (HA) allows a pair of ScaleArc servers to function as a redundant cluster. This KB describes the steps to configure High Availability cluster in ScaleArc.
Pre-Requisites to configure HA:
- Two ScaleArc Nodes with v18.104.22.168 or later.
- The Network Interface on which the HA will be configured should be assigned a STATIC IP Address and it should be visible in the ScaleArc UI.
- The following types of IP address are not recommended to be used for HA configuration.
- Dynamically assigned IP address (DHCP).
- NATted IP addresses.
- Both ScaleArc Nodes must be able to reach each other over the network.
- The configuration of both the ScaleArc nodes must be identical.
- Choose an Option to Configure Fencing: ScaleArc Fencing intelligently resolves a split-brain situation between two nodes in HA mode. The algorithm employs a 'capture the flag technique' which requires storage of metadata reliably along the traffic path. This storage can be a database server configured inside a ScaleArc cluster, a -third– party external database server, or a Linux-based SSH server.
Before proceeding you must have a VIP available to have your applications send traffic to ScaleArc cluster (this step is not required for AWS as the ELB ip will take care of this). You can
follow KB article below to add VIP tp Scalearc:
- On the Primary Scalearc Node, Go to Settings >> HA settings:
- Select an option for fencing. (Scalearc cluster / External DB server / SSH Server).
- Enter Remote Interface (Interface of the Secondary Node) and Remote IP (IP of the Secondary Node).
- Click on “Configure HA” and enter the UI credentials of the Secondary Scalearc Instance, Click "Submit" once done.
- ScaleArc will ask you to login to the Primary Node once HA configuration is successfully completed.
- Log in and check the HA Configuration under Settings >> HA settings.