红帽全球峰会第 4 章 Configuring a Red Hat High Availability cluster on Microsoft Azure
A high availability (HA) cluster offers to group RHEL nodes so that workloads are automatically redistributed if a node fails. You can deploy HA clusters on public cloud platforms, including Microsoft Azure. The process for setting up HA clusters on Azure is comparable to configuring them in traditional, non-cloud environments.
To configure a Red Hat HA cluster on Azure that uses virtual hard drive (VHD) instances as cluster nodes, see the following sections. You have several options for obtaining RHEL images for the cluster. For details, see Available RHEL image types for public cloud.
Before you begin, make sure to complete following steps:
- You have created a Red Hat account
- You have signed up and set up an Azure account.
A high-availability (HA) cluster links a set of computers (called nodes) to run a specific workload. HA clusters offer redundancy to handle hardware or software failures. When a node in the HA cluster fails, the Pacemaker cluster resource manager quickly distributes the workload to other nodes, ensuring that services on the cluster continue without noticeable downtime.
You can also run HA clusters on public cloud platforms. In this case, you would use virtual machine (VM) instances in the cloud as the individual cluster nodes. Using HA clusters on a public cloud platform has the following benefits:
- Improved availability: In case of a VM failure, the workload is quickly redistributed to other nodes, so running services are not disrupted.
- Scalability: You can start additional nodes when demand is high and stop them when demand is low.
- Cost-effectiveness: With the pay-as-you-go pricing, you pay only for nodes that are running.
- Simplified management: Some public cloud platforms offer management interfaces to make configuring HA clusters easier.
To enable HA on your RHEL systems, Red Hat offers a HA Add-On. You can configure a RHEL cluster with Red Hat HA Add-On to manage HA clusters with groups of RHEL servers. Red Hat HA Add-On gives access to integrated and streamlined tools. With cluster resource manager, fencing agents, and resource agents, you can set up and configure the cluster for automation. The Red Hat HA Add-On offers the following components for automation:
-
Pacemaker, a cluster resource manager that offers both a command line utility (pcs) and a GUI (pcsd) to support many nodes -
CorosyncandKronosnetto create and manage HA clusters - Resource agents to configure and manage custom applications
- Fencing agents to use cluster on platforms such as bare-metal servers and virtual machines
The Red Hat HA Add-On handles critical tasks such as node failures, load balancing, and node health checks for fault tolerance and system reliability.
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