Libro sobre Proxmox maestria
Fencing
Fencing is a concept of isolating a node or its resources during node failure so that other nodes cannot access the same resources causing data corruption. In Proxmox, fencing prevents multiple nodes from running on the same virtual machine or cluster-specific services. Without fencing, Proxmox HA cannot be set up. Fencing ensures data integrity during a failure by preventing all nodes from running on the same virtual machine or cluster services at the same time. There are several ways to set up fencing such as the following:
⚫ Using fence_xvmd: The host node needs to be configured with fence_xvmd while the virtual machine needs to be configured with fence_xvm
Using managed switch with SNMP
Using libvirt: Both the host and virtual machines need to be configured with libvirt
Using Intelligent Platform Managament Interface or IPMI
⚫ Using managed Power Distribution Unit or PDU
In this chapter, we are going to learn how to set up fence and HA with managed PDU as a hardware fencing device.
Managed PDUs are physical hardware devices, which enable a Proxmox node to power cycle another node during a failover before starting the HA service. An example of such a fencing device is APC-managed PDU AP7921 (http://www.apc. com/products/resource/include/techspec_index.cfm?base_sku=AP7921).
A managed PDU allows an administrator to remotely power cycle a device connected to the power outlet of the unit. This is useful when IPMI is not available and a node needs to be rebooted. By logging in remotely into a PDU user interface, any power outlet of the PDU can be turned on or off.
There are the following two types of fencing available:
⚫ Resource-level fencing
Node-level fencing