Hyper-V replication automatic failover and load balancing of VMs (no shared disk)

Evidian SafeKit brings high availability to Hyper-V. This article explains how to implement quickly a Hyper-V cluster without shared disk and without specific skills. The high availabity module hyperv.safe and a free trial are offered in the installation tab below.

Note that you can implement with the same product real-time replication and failover of other applications (database or other): see other examples of mirror modules here.

This clustering solution is recognized as the simplest to implement by our customers and partners. This solution solves only problems of hardware failures (20% of problems) including the complete failure of a computer room. If you want a complete solution that solves hardware failures (20% of problems), software failures (40% of problems) including smooth upgrade server by server and human errors (40% of problems) thanks to its simplicity, look at high availability at the application level and read this article VM HA vs Application HA.

Principle

The replication of VMs is synchronous and real-time between two Hyper-V servers. Only modifications made inside files making up a virtual machine are replicated. Note that SafeKit implements synchronous real-time replication and not the traditional Hyper-V asynchronous replication. This feature is important because with an asynchronous replication, there is data loss on a failover as explained in this article: synchronous replication vs asynhronous replication.

When the Hyper-V server fails, there is an automatic failover of VMs on the other Hyper-V server. And when the failed server is restarted, there is an automatic reintegration of VM files without stopping them on the other active Hyper-V server.

Each VM is replicated and automatically restarted independently. Some VMs can run on the first Hyper-V server and are replicated and restarted on the second Hyper-V server. Other VMs can run on the second Hyper-V server and are replicated and restarted on the first Hyper-V server. The load balancing of VMs between the two servers are controlled by the administrator through the SafeKit web console. By clicking on a swap button, the administrator can move a VM from one Hyper-V server to the other.

The solution requires no shared disk and no special Windows configuration. Only 2 Windows servers are necessary. The SafeKit software is installed on both of them.

Features

Full synchronous real-time replication of a virtual machine with failover
Load balancing of virtual machines between 2 Hyper-V servers with crossed replication
A centralized and ergonomic console to manage all VMs
Interesting offer for a reseller with zero integration with applications
In less than 10 minutes, a reseller knows how to create a Hyper-V cluster: see this video
Another video presents the replication of VM checkpoints and settings
Interesting for HA solutions which cannot be integrated at the application level (Active Directory, Microsoft Exchange...)
Interesting for applications running on unsupported OS and integrated in a Hyper-V VM replicated by SafeKit

Note that this solution is limited to replication and failover of 25 VMs.

Note also that SafeKit is able to automatically re-synchronize a failed Hyper-V server without any manual operation and without stopping the VMs. It is an important differentiator when comparing SafeKit to replication solutions whose failover only works once: reintegrating the failed server in the cluster requires complex and non-automated manual operations.

Installation

Configuration

Troubleshooting

Advanced Configuration

Support

Installation of a SafeKit / Hyper-V high availability cluster with synchronous replication and failover

Prerequisites

you need Hyper-V installed on 2 nodes (virtual machines or physical servers)
on Windows, with Windows services manager, put Hyper-V services with Boot Startup Type = Manual on both nodes. SafeKit controls start of Hyper-V services in start_prim. Edit start_prim during the configuration to check if you have put all services in Manual boot including the new ones that you can add.

Package installation on Windows

Install the free version of SafeKit on 2 Windows nodes with Hyper-V services installed on both nodes
Download the Windows module
Put hyperv.safe under C:\safekit\Application_Modules\demo\ (create the demo directory if it does not exist)
To open the Windows firewall, on both nodes start a command line as administrator, goto C:\safekit\private\bin and type .\firewallcfg.cmd add
For synchronizing SafeKit at boot and at shutdown, on both nodes start a command line as administrator, goto C:\safekit\private\bin and type .\addStartupShutdown.cmd

Go to the configuration tab

Configuration of a SafeKit / Hyper-V high availability cluster with synchronous replication and failover

Configuration instructions

The Hyper-V configuration is presented with a virtual machine named VM1. You will have to repeat this configuration for all VMs that you want to replicate. SafeKit supports up to 25 virtual machines.

Important: all the configuration is made from a single browser.

Launch the web console in a browser by connecting to http://localhost:9010 (next image)

Enter IP address of the first node and click on Confirm (next image)

Click on New node and enter IP address of the second node (next image)
Then click on the red floppy disk to save the configuration (next image)

In the Configuration tab, click on hyperv.safe (xxx.safe in the next image) then enter VM1 as the module name and Confirm (the console finds hyperv.safe in the demo/ directory that you previously filled)

Click on Validate (next image)

Before the SafeKit configuration, you have to make a configuration in Hyper-V manager (see demonstration):

Export with the name VM1 the target VM in a directory that will be replicated, for example: D:\Repli-Hyper-V
Remove the target VM from the inventory of Hyper-V manager
Import the VM1 virtual machine into Hyper-V manager

Then in SafeKit configuration (next image), give the path of the replicated directory (D:\Repli-Hyper-V in next image) where the VM has been exported and enter the exported VM name (VM1 in next image).

Click on Validate (previous image)

Click on Configure (previous image)

Check the success green message on both servers and click on Next (previous image).

Select the node with the most up-to-date replicated directories and click on start it to make the first resynchronization in the right direction (previous image). Before this operation, we suggest you to make a copy of replicated directories before starting the cluster to avoid any errors.

Start the second node (previous image) which becomes SECOND green (next image) after resynchronisation of all replicated directories (binary copy from node 1 to node 2).

The replication and failover is operational for VM1. VM1 is running on the PRIM node (previous image). Only modifications inside the Hyper-V files defining VM1 are replicated in real-time in this state.

Test

Check with Hyper-V manager that VM1 is started on the primary server and stopped on the secondary server.

Stop the PRIM node by scrolling down the menu of the primary node and by clicking on Stop. Check that there is a failover on the SECOND node. And check the failover of VM1 with Hyper-V manager.

Troubleshooting of a SafeKit / Hyper-V high availability cluster with synchronous replication and failover

Module log

Read the module log to understand the reasons of a failover, of a waiting state on the availability of a resource etc...
To see the module log of the primary server (next image):

click on the Control tab
click on W12R2server74/PRIM (it becomes blue) on the left side to select the server
click on Module Log
click on the Refresh icon (green arrows) to update the console
click on the floppy disk to save the module log in a .txt file and to analyze in a text editor

Repeat the same operation to see the module log of the secondary server.

Application log

Read the application log to see the output messages of the stat_prim and stop_prim restart scripts.
To see the application log of the primary server (next image):

click on the Control tab
click on W12R2server74/PRIM (it becomes blue) on the left side to select the server
click on Application Log to see messages when starting and stopping VM1
click on the Refresh icon (green arrows) to update the console
click on the floppy disk to save the application log in a .txt file and to analyze in a text editor

Repeat the same operation to see the application log of the secondary server.

Advanced configuration of a SafeKit / Hyper-V high availability cluster with synchronous replication and failover

In Advanced Configuration tab (next image), you can edit internal files of the module: bin/start_prim and bin/stop_prim and conf/userconfig.xml (next image on the left side). If you make change in the internal files here, you must apply the new configuration by a right click on the blue icon/xxx on the left side (next image): the interface will allow you to redeploy the modified files on both servers.

Configure boot start (next image on the right side) configures the automatic boot of the module when the server boots. Do this configuration on both servers once the high availability solution is correctly running. Note that for synchronizing SafeKit at boot and at shutdown, on both nodes, you must before start a command line as administrator, and run .\addStartupShutdown.cmd in C:\safekit\private\bin.

Key differentiators of SafeKit vs Microsoft Hyper-V cluster and VMware HA

SafeKit with the Hyper-V module	Microsoft Hyper-V Cluster & VMware HA

No shared disk - synchronous real-time replication instead with no data loss	Shared disk and specific extenal bay of disk
Remote sites = no SAN for replication	Remote sites = replicated bays of disk across a SAN
No specific IT skill to configure the system	Specific IT skills to configure the system

Note that the Hyper-V/SafeKit solution is limited to replication and failover of 25 VMs.

Key differentiators of high availability at the virtual machine level or at the application level

VM HA with the SafeKit Hyper-V module	Application HA with SafeKit application modules

Replicates too much data (App+OS)	Replicates only application data
Reboot of VM on hypervisor 2 if hypervisor 1 crashes: recovery time depending on the OS reboot	Quick recovery time with restart of App on OS2 if crash of VM1: around 1 mn or less (see RTO/RPO here)
No application checker and software failover	Application checker and software failover
Risk of downtime when fixing OS or App (single image)	Smooth upgrade of OS1 or OS2 or App (two images)
Generic solution for any application / OS	Simple integration with application modules

Key differentiators of the SafeKit high availability technology

High availability architectures comparison
Feature	SafeKit cluster	Other clusters
Software clustering vs hardware clustering More information...	A simple software cluster with the SafeKit package just installed on two servers	Complex hardware clustering with external storage or network load balancers
Shared nothing vs a shared disk cluster More information...	SafeKit is a shared-nothing cluster: easy to deploy even in remote sites	A shared disk cluster is complex to deploy
Application High Availability vs Full Virtual Machine High Availability More information...	Application HA supports hardware failure and software failure with a quick recovery time (RTO around 1 mn or less). Smooth upgrade of application and OS possible server by server (version N and N+1 can coexist)	Full virtual machines HA supports only hardware failure with a VM reboot and a recovery time depending on the OS reboot. Smooth upgrade not possible
High availability vs fault tolerance	No dedicated server. Each server can be the failover server of the other one. Software failure with restart in another OS environment. Smooth upgrade of application and OS possible server by server (version N and N+1 can coexist)	Secondary server dedicated to the execution of the same application synchronized at the instruction level. Software exception on both servers at the same time. Smooth upgrade not possible
Synchronous replication vs asynchronous replication More information...	SafeKit implements real-time synchronous replication with no data loss in case of failure	With asynchronous replication, there is data loss on failure
Byte-level file replication vs block-level disk replication More information...	SafeKit implements real-time byte-level file replication and is simply configured with application directories to replicate even in the system disk	Block-level disk replication is complex to configure and requires to put application data in a special disk
Heartbeat, failover and quorum to avoid 2 master nodes More information...	To avoid 2 masters, SafeKit proposes a simple split brain checker configured on a router	To avoid 2 masters, other clusters require a complex configuration with a third machine, a special quorum disk, a special interconnect
Network load balancing More information...	No dedicated proxy servers and no special network configuration are required in a SafeKit cluster for network load balancing	Special network configuration is required in other clusters for network load balancing

Best high availability use cases with SafeKit

Best use cases [+]

1 - OEM Software	2 - Distributed Enterprise	3 -Remote Sites

A software publisher uses SafeKit as an OEM software for high availability of its application	A distributed enterprise deploys SafeKit in many branches without specific IT skills	SafeKit is deployed in two remote sites without the need for replicated bays of disks through a SAN

Testimonials

The ideal product for a software publisher
“SafeKit is the ideal application clustering solution for a software publisher. We currently have deployed more than 80 SafeKit clusters worldwide with our critical TV broadcasting application.”
The product very easy to deploy for a reseller
“WithNCompany has deployed in South Korea many SafeKit high availability solutions with the Hanwha Video Surveillance Platform. SafeKit is appreciated because the product is easy to install and very quickly deployed.”
The product to gain time for a system integrator
“Thanks to a simple and powerful product, we gained time in the integration and validation of our critical projects like the supervision of Paris and Marseille metro lines (the control rooms).”

Video surveillance (CCTV) [+]
In video surveillance systems, Evidian SafeKit implements high availability with synchronous replication and failover of
- Milestone XProtect,
- Hanwha Wisenet SSM,
- Siemens CCTV Video Surveillance and Access Control (SiPass)
Use case: In South Korea, WithNCompany deploys high availability of the Hanwha Video Surveillance platform with SafeKit.
TV broadcasting [+]
Harmonic is using SafeKit as a software OEM high availability solution and deploys it with its TV broadcasting solutions over satellites, terrestrials, cable, IPTV.
Over 80 SafeKit clusters are deployed on Windows for replication of Harmonic database and automatic failover of the critical application.
Philippe Vidal, Product Manager, Harmonic says:
“SafeKit is the ideal application clustering solution for a software publisher looking for a simple and economical high availability software. We are deploying SafeKit worldwide and we currently have more than 80 SafeKit clusters on Windows with our critical TV broadcasting application through terrestrial, satellite, cable and IP-TV. SafeKit implements the continuous and real-time replication of our database as well as the automatic failover of our application for software and hardware failures. Without modifying our application, it was possible for us to customize the installation of SafeKit. Since then, the time of preparation and implementation has been significantly reduced.”
Finance [+]
The European Society of Warranties and Guarantees in Natixis uses SafeKit as a high availability solution for its applications.
Over 30 SafeKit clusters are deployed on Unix and Windows in Natixis.
Industry [+]
Fives Syleps, the Sydel software editor implements high availability of its ERP with SafeKit and deploys the solution in the food industry.
Over 20 SafeKit clusters are deployed on Unix with Oracle.

Air traffic control [+]
Air traffic control systems supplier, Copperchase, deploys SafeKit high availability in airports.
Over 20 SafeKit clusters are deployed on Windows.
Tony Myers, Director of Business Development says:
"By developing applications for air traffic control, Copperchase is in one of the most critical business activities. We absolutely need our applications to be available all the time. We have found with SafeKit a simple and complete clustering solution for our needs. This software combines in a single product load balancing, real time data replication with no data loss and automatic failover. This is why, Copperchase deploys SafeKit for air traffic control in airports in the UK and the 30 countries where we are present."
Bank [+]
Software vendor Wellington IT deploys SafeKit high availability with its banking application for Credit Unions in Ireland and UK.
Over 25 SafeKit clusters are deployed on Linux with Oracle.
Peter Knight, Sales Manager says:
"Business continuity and disaster recovery are a major concern for our Locus banking application deployed in numerous Credit Unions around Ireland and the UK. We have found with SafeKit a simple and robust solution for high availability and synchronous replication between two servers with no data loss. With this software solution, we are not dependent on a specific and costly hardware clustering solution. It is a perfect tool to provide a software high availability option to an application of a software vendor."
Transport [+]
Paris transport company (RATP) chose the SafeKit high availability and load balancing solution for the centralized control room of line 1 of the Paris subway.
20 SafeKit clusters are deployed on Windows and Linux.
Stéphane Guilmin, RATP, Project manager says:
"Automation of line 1 of the Paris subway is a major project for RATP, requiring a centralized command room (CCR) designed to resist IT failures. With SafeKit, we have three distinct advantages to meet this need. Firstly, SafeKit is a purely software solution that does not demand the use of shared disks on a SAN and network boxes for load balancing. It is very simple to separate our servers into separate machine rooms. Moreover, this clustering solution is homogeneous for our Windows and Unix platforms. SafeKit provides the three functions that we needed: load balancing between servers, automatic failover after an incident and real time data replication."
And also, Philippe Marsol, Atos BU Transport, Integration Manager says:
“SafeKit is a simple and powerful product for application high availability. We have integrated SafeKit in our critical projects like the supervision of Paris metro Line 4 (the control room) or Marseille Line 1 and Line 2 (the operations center). Thanks to the simplicity of the product, we gained time for the integration and validation of the solution and we had also quick answers to our questions with a responsive Evidian team.”
Healthcare [+]
The software integrator Systel deploys SafeKit high-availability solution in firefighter and emergency medical call centers.
Over 30 SafeKit clusters are deployed on Windows with SQL Server.
Marc Pellas, CEO says:
"SafeKit perfectly meets the needs of a software vendor. Its main advantage is that it brings in high availability through a software option that is added to our own multi-platform software suite. This way, we are not dependent on a specific and costly hardware clustering solution that is not only difficult to install and maintain, but also differs according to client environments. With SafeKit, our firefighter call centers are run with an integrated software clustering solution, which is the same for all our customers, is user friendly and for which we master the installation up to after-sales support."
Government [+]
ERP high availability and load balancing of the French army (DGA) are made with SafeKit.
14 SafeKit clusters are deployed on Windows and Linux.
Alexandre Barth, Systems administrator says:
"Our production team implemented the SafeKit solution without any difficulty on 14 Windows and Linux clusters. Our critical activity is thus secure, with high-availability and load balancing functions. The advantages of this product are easy deployment and administration of clusters, on the one hand, and uniformity of the solution in the face of heterogeneous operating systems, on the other hand."

Real-time file replication and failover: click on the blue buttons
Mirror modules	Windows	Linux
Microsoft SQL Server		-
Oracle
MySQL
PostgreSQL
Firebird
Hyper-V		-
Milestone XProtect		-
Hanwha Wisenet SSM		-
New application
Amazon AWS mirror
Microsoft Azure mirror
Google GCP mirror
Cloud generic mirror

Network load balancing and failover: click on the blue buttons
Farm modules	Windows	Linux
IIS		-
Apache
New application
Amazon AWS farm
Microsoft Azure farm
Google GCP farm
Cloud generic farm

Hyper-V replication automatic failover and load balancing of VMs (no shared disk)

Evidian SafeKit

How to implement Hyper-V replication automatic failover and load balancing of VMs with the SafeKit software (no shared disk)?

Principle

Features

Installation of a SafeKit / Hyper-V high availability cluster with synchronous replication and failover

Prerequisites

Package installation on Windows

Go to the configuration tab

SafeKit High Availability Differentiators against Competition

High availability architectures comparison

Customers of SafeKit High Availability Software in all Business Activities

Best use cases [+]

Testimonials

The ideal product for a software publisher

The product very easy to deploy for a reseller

The product to gain time for a system integrator

Video surveillance (CCTV) [+]

TV broadcasting [+]

Finance [+]

Industry [+]

Air traffic control [+]

Bank [+]

Transport [+]

Healthcare [+]

Government [+]

Demonstrations of SafeKit High Availability Software

SafeKit Webinar

Microsoft SQL Server Cluster

Apache Cluster

Hyper-V Cluster

Free On-Line Training on SafeKit High Availability Software

1. Introduction [+]

2. Installation and configuration [+]

3. Advanced configuration [+]

4. Administration [+]

5. Guides [+]

SafeKit Modules for Plug&Play High Availability Solutions

Network load balancing and failover: click on the blue buttons

Farm modules

Windows

Linux

Real-time file replication and failover: click on the blue buttons

Mirror modules

Windows

Linux

News

Events

Partners