KVM: the simplest high availability cluster with real-time replication, automatic failover and load balancing of VMs between two redundant servers without shared disk

Evidian SafeKit

How to implement a Linux KVM cluster with replication, automatic failover and load balancing of VMs and with the SafeKit software between two redundant servers without shared disk?

A Linux KVM cluster with SafeKit: real-time replication, load balancing and failover between two redundant servers

Evidian SafeKit brings high availability to KVM between two redundant servers. This article explains how to implement quickly a KVM cluster without shared disk and without specific skills. The high availabity module kvm.safe and a free trial are offered in the Installation tab below.

Note that SafeKit is a generic product. You can implement with the same product real-time replication and failover of new directories and services, databases, docker containers, full Hyper-V or KVM virtual machines, Cloud applications. 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

  • hardware failures (20% of problems), including the complete failure of a computer room,
  • and human errors (40% of problems) thanks to its ease of use, including a very simple administration web console to configure, control and monitor clusters,
  • but it does not solve software failures (40% of problems), including smooth upgrade server by server,
  • and the recovery time in case of failure depends on the time to reboot VMs.

For a complete solution with quick recovery time, consider high availability at the application level and read this article VM HA vs Application HA.

Note that the solution presented here allows replication and failover at the virtual machine level. But SafeKit also offers a solution with replication and failover at the container level (Docker).

Principle

The replication of VMs is synchronous and real-time between two KVM 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 KVM 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 KVM server fails, there is an automatic failover of VMs on the other KVM server. And when the failed server is restarted, there is an automatic reintegration of VM files without stopping them on the other active KVM server.

Each VM is replicated and automatically restarted independently. Some VMs can run on the first KVM server and are replicated and restarted on the second KVM server. Other VMs can run on the second KVM server and are replicated and restarted on the first KVM 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 KVM server to the other.

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

Features

  • No shared disk
  • Synchronous real-time replication of a virtual machine with failover
  • Very simple solution to implement
  • Load balancing of several virtual machines between 2 KVM servers with crossed replication
  • A centralized and ergonomic console to manage all VMs
  • Interesting offer for a reseller with zero integration with applications
  • Interesting for HA solutions which cannot be integrated at the application level (application + OS in a virtual machine replicated by SafeKit)
  • Simple solution for HA of a Kubernetes application on premise: put Minikube + containers + etcd database + OS in a VM replicated by SafeKit; no need to install a Kubernetes cluster on premise
  • Interesting for applications running on unsupported OS and integrated in a KVM 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 KVM 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.

Free trial + kvm.safe module and step by step installation procedure of SafeKit between two redundant Linux KVM servers

Customers of SafeKit High Availability Software in all Business Activities

  • Best high availability use cases with SafeKit

    Best use cases [+]

    Like   OEM Software Like   Distributed Enterprise Like   Remote Sites
    Application Clustering Software for a Software Publisher High Availability Software in a Distributed Enterprise Business Continuity and Disaster Recovery without a replicated SAN
    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

    Like  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.

    Like  The product very easy to deploy for a reseller

    “Noemis, a value added distributor of Milestone Video Surveillance, has assisted integrators to deploy the SafeKit redundancy solution on many projects such as city surveillance, datacenters, stadiums and other critical infrastructures. SafeKit is a great product, and Evidian provides a great support.”

    Like  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 metro lines (the control rooms).”


  • High availability of Video Surveillance Platforms with SafeKit

    Video surveillance and access control [+]

    In video surveillance systems and access control, Evidian SafeKit implements high availability with synchronous replication and failover of

    Sebastien Temoin, Technical and Innovation Director, NOEMIS, value added distributor of Milestone solutions:

    "SafeKit by Evidian is a professional solution making easy the redundancy of Milestone Management Server, Event Server, Log Server. The solution is easy to deploy, easy to maintain and can be added on existing installation. We have assisted integrators to deploy the solution on many projects such as city surveillance, datacenters, stadiums and other critical infrastructures. SafeKit is a great product, and Evidian provides great support. Happy to help if you have any questions."

    Use cases:


  • Harmonic has deployed more than 80 SafeKit clusters for high availability of its TV broadcasting application over satellites, terrestrials, cable, IPTV.

    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.”


  • The European Society of Warranties and Guarantees in Natixis uses SafeKit as a high availability solution for its applications.

    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.


  • Fives Syleps implements high availability of its ERP with SafeKit and deploys the solution in the food industry.

    Industry [+]

    Fives Syleps implements high availability of its ERP with SafeKit and deploys the solution in the food industry.

    Over 20 SafeKit clusters are deployed on Linux and Windows with Oracle.

    Testimonial of Fives Syleps:

    "The automated factories that we equip rely on our ERP. It is not possible that our ERP is out of service due to a computer failure. Otherwise, the whole activity of the factory stops.

    We chose the Evidian SafeKit high availability product because it is an easy to use solution. It is implemented on standard servers and does not require the use of shared disks on a SAN and load balancing network boxes.

    It allows servers to be put in remote computer rooms. In addition, the solution is homogeneous for Linux and Windows platforms. And it provides 3 functionalities: load balancing between servers, automatic failover and real-time data replication.”


  • Air traffic control systems supplier, Copperchase, deploys SafeKit high availability in airports.

    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."


  • Software vendor Wellington IT deploys SafeKit high availability with its banking application for Credit Unions in Ireland and UK.

    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."


  • 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.

    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 Linuxplatforms. 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.”


  • The software integrator Systel deploys SafeKit high-availability solution in firefighter and emergency medical call centers.

    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."


  • ERP high availability and load balancing of the French army (DGA) are made with SafeKit.

    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."

     


SafeKit High Availability Differentiators against Competition

Demonstrations of SafeKit High Availability Software

SafeKit Webinar

This webinar presents in 10 minutes Evidian SafeKit.

In this webinar, you will understand:

  • mirror and farm clusters
  • cost savings against hardware clustering solutions
  • best use cases
  • the integration process for a new application

Microsoft SQL Server Cluster

This video shows a mirror module configuration with synchronous real-time replication and failover.

The file replication and the failover are configured for Microsoft SQL Server but it works in the same manner for other databases.

Free trial here

Apache Cluster

This video shows a farm module configuration with load balancing and failover.

The load balancing and the failover are configured for Apache but it works in the same manner for other web services.

Free trial here

Hyper-V Cluster

This video shows a Hyper-V cluster with full replications of virtual machines.

Virtual machines can run on both Hyper-V servers and they are restarted in case of failure.

Free trial here

SafeKit Modules for Plug&Play High Availability Solutions