High Availability Cluster

Note: Article about Proxmox VE 2.0

Introduction

Proxmox VE High Availability Cluster (Proxmox VE HA Cluster) enables the definition of high available virtual machines. In simple words, if a virtual machine (VM) is configured as HA and the physical host fails, the VM is automatically restarted on one of the remaining Proxmox VE Cluster nodes.

The Proxmox VE HA Cluster is based on proven Linux HA technologies, providing stable and reliable HA service.

Update to the latest version

Before you start, make sure you have installed the latest packages, just run this on all nodes:

aptitude update && aptitude full-upgrade

System requirements

If you run HA, only high end server hardware with no single point of failure should be used. This includes redundant disks (Hardware Raid), redundant power supply, UPS systems, network bonding.

• Fully configured Proxmox_VE_2.0_Cluster, with at least 3 nodes (maximum supported configuration: currently 16 nodes per cluster). Note that, with certain limitations, 2-node configuration is also possible (Two-Node_High_Availability_Cluster).
• Shared storage (SAN or NAS/NFS for Virtual Disk Image Store for HA KVM)
• Reliable network, suitable configured
• NFS for Containers
• Fencing device(s) - reliable and TESTED!

HA Configuration

The configuration of fence devices is CLI only. Adding and managing VM´s and containers for HA should be done via GUI.

Fencing is a needed part for Proxmox VE 2.0 HA, without fencing, HA will not start working.

Configure VM or Containers for HA

Review again if you have everything you need and if all systems are running reliable. It makes no sense to configure HA cluster setup on unreliable hardware.

• See High_Availability_Cluster#System_requirements

Enable a KVM VM or a Container for HA

See also the video tutorial on Proxmox VE Youtube channel

Note: Make sure that the VMs or CTs are not running when you add them to HA.

HA Cluster maintenance (node reboots)

If you need to reboot a node, e.g. because of a kernel update you need to stop rgmanager. By doing this, all resources are stopped and moved to other nodes. All KVM guests will get a ACPI shutdown request (if this does not work due to VM internal setting just a 'stop').

You can stop the rgmanager service via GUI or just run:

/etc/init.d/rgmanager stop

The command will take a while, monitor the "tasks" and the VM´s and CT´s on the GUI. as soon as the rgmanager is stopped, you can reboot your node. as soon as the node is up again, continue with the next node and so on.

Video Tutorials

Proxmox VE Youtube channel

Certified Configurations and Examples

• Intel Modular Server HA
• tbe

Testing

Before going in production do as many tests as possible.

Useful command line tools

Here is a list of useful CLI tools:

• clustat - Cluster Status Utility
• clusvcadm - Cluster User Service Administration Utility
• ccs_config_validate - validate cluster.conf file
• fence_tool - a utility for the fenced daemon
• fence_node - a utility to run fence agents