Libro sobre Proxmox maestria
Proxmox HA - Zero Downtime
In a small environment this can be manageable, but in a large environment of hundreds of virtual machines and nodes, constant monitoring is just not realistic. Although there can be monitoring software in place to automatically alert administrators about any node failure, without HA the administrator will have to manually move or migrate any virtual machine from a faulty node. This can cause longer downtime due to human response time. HA takes the longer response time out of the equation by simply moving or migrating virtual machines to a node as soon as server hardware failure occurs.
To set up a functional HA, it is important to have all the virtual machines on a shared storage. Proxmox HA only handles Proxmox nodes and virtual machines within a Proxmox cluster. These HA features are not be confused with shared storage redundancy, which Proxmox can utilize for it's HA deployment. A third-party shared storage may provide its own HA features.
There can be levels of redundancy in a Proxmox computing node, such as the use of RAID, redundant power supply, aggregated network link or bond, and so on. HA in Proxmox is not a replacement for any of these layers. It just facilitates redundancy features for virtual machines to keep running during a node failure. It should be noted that in a Proxmox node, a reboot due to an applied update will cause all HA-enabled virtual machines to shut down and move to the next available Proxmox node and restart again. In such a situation, it may be necessary to manually live migrate virtual machines first, which requires minimum interruption, before rebooting the node.
Proxmox HA can be set up with just two Proxmox nodes. But since this type of setup is not ideal for a production environment, three or more Proxmox nodes are recommended to set up a Proxmox HA because with three nodes or more, achieving Quorum is possible. Quorum is the minimum number of votes required for a Proxmox cluster operation. This minimum number is the total vote by a majority of the nodes. For example, in a cluster of three Proxmox nodes, a minimum vote of two Proxmox nodes is required to form a Quorum. In another example of clusters with eight-nodes, a minimum vote of 5 Proxmox nodes is required to form a Quorum. With just two nodes, the ratio of vote remains at 1:1, so no Quorum is possible. To know more about how to set up High Availability with just two Proxmox nodes, visit http:// pve.proxmox.com/wiki/Two-Node_High_Availability_Cluster. Almost all the configurations of Proxmox HA can be done from the GUI, except the fencing configuration. This portion of the setup must be done through the CLI.