This guide walks you through creating the following configuration as an example of using a cluster environment on the Azure cloud.
- LifeKeeper for Windows cluster (2-node cluster) Multi-NIC configuration
- Shared data space (using data mirroring through DataKeeper replication)
- IP resources, Oracle resources or PostgreSQL resources
This document is based on a configuration validated and tested by SIOS.
The contents of this document are based on tests performed on Azure as of March 2020. SIOS does not warranty the compatibility of these settings on future iterations of Azure or LifeKeeper. Refer to the corresponding documentation as necessary and update your settings accordingly.
The procedures in this guide require licenses for the required software, including LifeKeeper for Windows, Oracle Database, and PostgreSQL.
- In this configuration, network address translation (NAT) via ILB is used for network communication. The TCP port number for NAT must be set to a fixed number in advance. Therefore, it is not possible to protect applications that may have problems with NAT communication on only fixed TCP port numbers. This includes the following applications:
- Applications that use multiple connections to communicate with clients, those that dynamically change the server-side port number (e.g., FTP active mode)
- Applications that communicate over non-TCP protocols (ICMP, etc.).
- Applications that use protocols other than TCP (ICMP, etc.) for communication.
- Applications in this configuration must be able to communicate with virtual IP addresses as well as the private IP addresses of the active and standby nodes in order to respond to the health probes. Therefore, the IP address from which the application waits for a connection must be configurable to any IP address (INADDR_ANY).
The terms used in this document are described as follows.
- Internal Load Balancing (ILB) – A feature that provides load balancing between virtual machines that reside within Azure cloud services or geographically confined virtual networks.
- VIP protected by IP resources – A virtual IP address created with LifeKeeper for Windows.
- VIP configured by ILB – The virtual IP address of the Internal Load Balancing created on Azure.
- Azure private IP address – A private address used on an Azure virtual network.
LifeKeeper for Windows Requirements in Azure
- LifeKeeper clusters rely on an Azure Internal Load Balancer (ILB) for communication with protected applications. The ILB needs two network adapters on each LifeKeeper node in order to work properly, therefore multiple network interfaces must be defined for each cluster node.
- LifeKeeper host names must be all upper-case. When defining the cluster nodes in Azure, use upper-case host names.
- If your Azure instance includes an ephemeral disk, that disk should be used to store DataKeeper bitmaps for optimal replication performance.
- Azure provides two options for enhanced application availability. These options are 1) Availability Sets (AS), and 2) Availability Zones (AZ). Availability Zones are preferred, as they are a superset of Availability Sets. If your region provides Availability Zones, each LifeKeeper node should be configured in a different AZ; otherwise the nodes should be configured in a different Fault and Update domain in an Availability Set.