Evidian SafeKit brings high availability to Hanwha SSM, the CCTV video surveillance system.
This article explains how to implement quickly a Hanwha SSM cluster without shared disk and without specific skills. The high availabity module hanwha_ssm.safe and a free trial are offered in the installation section.
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. It is also a complete solution that solves hardware failures (20% of problems) including the complete failure of a computer room, software failures (40% of problems) including smooth upgrade server by server and human errors (40% of problems) thanks to its simplicity of administration.
How the Evidian SafeKit software simply implements Hanwha SSM high availability with real-time synchronous replication and failover without shared disk
On the previous figure, the server 1/PRIM runs Hanwha SSM services (any edition). Users are connected to the virtual IP address of the mirror cluster. SafeKit replicates files opened by Hanwha SSM services in real time. Only changes in the files are replicated across the network, thus limiting traffic (byte-level file replication). Names of file directories containing Hanwha SSM services data are simply configured in SafeKit. There are no pre-requisites on disk organization for the two servers. Directories to replicate may be located in the system disk. SafeKit implements synchronous replication with no data loss on failure contrary to asynchronous replication.
This demonstration shows the configuration of a generic mirror.safe module with Microsoft SQL Server but the configuration is the same with other applications.
Note that with the hanwha_ssm.safe module instead of the generic one, restart scripts are preconfigured for Hanwha SSM.
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.
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.”
“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.”
“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.”
“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.”
Key differentiators of Hanwha SSM replication and failover with the Evidian SafeKit mirror cluster
Evidian SafeKit mirror cluster with real-time file replication and failover
All clustering features
The solution includes all clustering features:
server failure monitoring, network failure monitoring, software failure monitoring,
automatic
Hanwha SSM restart with a quick recovery time, a virtual IP address switched in case of failure to automatically reroute clients
This is not the case with replication-only solutions like replication at the database level
Quick
Hanwha SSM restart is not ensured with full virtual machines replication. In case of hypervisor failure, a full VM must be rebooted on a new hypervisor with an unknown recovery time
The cluster configuration is very simple and made by means of a high availability application module.
There is no domain controller or active directory to configure on Windows. The solution works on Windows and Linux
Other services and other replicated directories can be added to the module to complement the SafeKit / Hanwha SSM high availability solution
This is not the case with asynchronous replication
Fully automated failback procedure
After a failure when a server reboots, the replication failback procedure
is fully automatic and the failed server reintegrates the cluster without stopping
Hanwha SSM on the only remaining server
This is not the case with most replication solutions particularly with replication at the database level. Manual operations are required for resynchronizing a failed server.
Hanwha SSM may even be stopped on the only remaining server during the resynchonization of the failed server
Replication of any type of data
The replication is working for
Hanwha SSM but also for any files which shall be replicated
This not the case for replication at the database level
File replication vs disk replication
The replication is based on file directories that can be located anywhere (even in the system disk)
This is not the case with disk replication
where special
Hanwha SSM configuration must be made to put the application data in a special disk
All SafeKit clustering features are working for 2 servers in remote sites. Performances of replication depends on the interconnect latency for real-time synchronous replication and on the bandwidth for resynchronizing data on a failed server
If both servers are connected to the same IP network through an extended LAN between two remote sites, the virtual IP address of SafeKit is working with rerouting at level 2
If both servers are connected to two different IP networks between two remote sites, the virtual IP address can be configured at the level of a load balancer.
SafeKit offers a health check: the load balancer is configured with a URL managed by SafeKit which returns OK on the primary server and NOT FOUND else. This solution is implemented for SafeKit in the Cloud but it can be also implemented with a load balancer on premise
This is not the case for most clustering solutions where a 3rd server is required for the quorum
Uniform high availability solution
SafeKit implements a mirror cluster with replication and failover. But it imlements also a farm cluster with load balancing and failover.
Thus a N-tiers architecture can be made highly available and load balanced with the same solution on
Windows and Linux (same installation, configuration, administration with the SafeKit console or with the command line interface). This is unique on the market
This is not the case with an architecture mixing different technologies for load balancing, replication and failover
Supports multiple heartbeats and vitual IP addresses
Offers configurable software, hardware and network checkers
For the quorum, does not require a special disk or a third machine or a dedicated link between both servers
Automatic failover of Hanwha SSM services with a recovery time in the order of one minute
Automatic failback when a server comes back after a failure (no manual operation)
A very simple console to deploy the solution and to maintain it afterwards for end-customer
Supports human errors (40% of causes of unavailability) thanks to its simplicity
Supports software failures (40% of causes of unavailability): regression on software update (version N and N+1 can coexist), Operating System frozen, software bug
Supports hardware and environment failures (20% of causes of unavailability), including the complete failure of a computer room with 2 nodes in two remote sites
What is the recovery time (RTO) [+]
RTO is the time during which the application is unavailable in case of failure. RTO of the SafeKit mirror solution is in the order of 1 mn.
For a hardware failure, RTO = heartbeat timeout (default 30 s, can be changed in userconfig.xml) + time to restart Hanwha SSM services.
For a software failure or an administrator restart, RTO = time to (cleanly) stop Hanwha SSM services + time to restart them.
Be careful, with solutions that reboot a full virtual machine in case of failure, the RTO is unpredictable as manual operations may be required after a hardware crash to reboot the virtual machine.
What is the data loss (RPO) [+]
RPO reflects the data loss in case of failure. RPO of the SafeKit mirror solution is 0 as the replication is synchronous and real-time.
Be careful, with asynchronous replication, RPO is not 0 and there is data loss in case of failure when the application restarts on the secondary server.
Supports multiple monitoring channels on multiple networks for server failure detection
Supports multiple vitual IP addresses
Offers configurable software, hardware and network checkers
Offers the mirror cluster with synchronous real-time replication and failover
Automatic failover with a recovery time in the order of a few seconds
Automatic failback when a server comes back after a failure (no manual operation)
A very simple console to deploy the solution and to maintain it afterwards for end-customer
Supports human errors (40% of causes of unavailability) thanks to its simplicity
Supports software failures (40% of causes of unavailability): regression on software update (version N and N+1 can coexist), Operating System frozen, software bug
Supports hardware and environment failures (20% of causes of unavailability), including the complete failure of a computer room with 2 nodes in two remote sites
What is the recovery time (RTO) [+]
RTO is the time during which the application is unavailable in case of failure. RTO of the SafeKit farm solution is in the order of a few seconds on hardware failure.
For a hardware failure, RTO = failure detection timeout through monitoring channels (default a few seconds): after the timeout the load balancing filters are reconfigured.
For a software failure or an administrator restart, RTO = time to (cleanly) stop Hanwha SSM services + time to restart them.
Install the free version of SafeKit on 2 Windows nodes with Hanwha SSM services installed on both nodes
Download the Windows module
The module contains the files userconfig.xml, start_prim and stop_prim described later in the internals section
Put hanwha_ssm.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
Configuration instructions
The configuration is presented with the web console connected to 2 Windows servers.
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)
Click on the red floppy disk to save the configuration (previous image)
In the Configuration tab, click on hanwha_ssm.safe (xxx.safe in the next image) then enter hanwha_ssm as the module name and Confirm (the console finds hanwha_ssm.safe in the demo/ directory that you previously filled)
Click on Validate (next image)
Change the path of replicated directories only if necessary (next image) and enter a virtual IP address. A virtual IP address is a new unused IP address in the same IP network as the IP addresses of the two nodes. The virtual IP address automatically switches in case of failover.
For information:
on the previous image, if a process name is displayed, it will be monitored with the action restart in case of failure. The services will be stopped an restarted locally on the primary server if this process disappears from the list of running processes. After 3 unsuccessful local restarts, the module is stopped on the primary server and the services are restarted on the secondary server.
start_prim and stop_prim (previous image) contain the start and the stop of Hanwha SSM services.
Check that the names of services in these scripts are those installed on your both machines (else modify them in the scripts).
on Windows, put Hanwha SSM services with Boot Startup Type = Manual on both servers (SafeKit controls start of Hanwha SSM services in start_prim).
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 cluster is operational with Hanwha SSM services running on the PRIM node and nothing running on the SECOND node (previous image). Only modifications inside files are replicated in real-time in this state.
Be careful, components which are clients of the Hanwha SSM services must be configured with the virtual IP address. The configuration can be made with a DNS name (if a DNS name has been created and associated with the virtual IP address).
Tests
Check with Windows Microsoft Management Console (MMC) that the Hanwha SSM services have been started on the primary server by the start_prim script
and stopped on the secondary server by the stop_prim script.
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 with Windows Microsoft Management Console (MMC), check the failover of Hanwha SSM services (stopped and started in the stop_prim and start_prim scripts).
Event logs of module and application
To see the module log of the primary server which contains events in the cluster (next image):
click on the Control tab
click on W12R2server74/PRIM (it becomes blue) on the left side
click on Module Log
click on the Refresh icon (green arrows) to update the console
check Verbose log to see all messages
click on the floppy disk to save the module log in a .txt file and to analyze in a text editor
To see the application log of the primary server which contains output messages from restart scripts (start_prim and stop_prim) (next image):
click on Application Log to see messages when starting and stopping Hanwha SSM services
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
To see the logs of the secondary server (previous image), click on W12R2server75/SECOND (it will become blue) on the left side and repeat the same operations.
In the secondary module log, you will find the volume and the reintegration time of replicated data.
Advanced configuration
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.
Support
For getting support on the call desk of https://support.evidian.com, get 2 Snaphots (2 .zip files), one for each server and upload them in the call desk tool (next image).
Internal files of the Windows hanwha_ssm.safe module
userconfig.xml
<!DOCTYPE safe>
<safe>
<service mode="mirror" defaultprim="alone" maxloop="3" loop_interval="24" failover="on">
<!-- Heartbeat Configuration -->
<!-- Names or IP addresses on the default network are set during initialization in the console -->
<heart pulse="700" timeout="30000">
<heartbeat name="default" ident="flow">
</heartbeat>
</heart>
<!-- Virtual IP Configuration -->
<!-- Replace
* VIRTUAL_TO_BE_DEFINED by the name of your virtual server
-->
<vip>
<interface_list>
<interface check="on" arpreroute="on">
<real_interface>
<virtual_addr addr="VIRTUAL_TO_BE_DEFINED" where="one_side_alias" />
</real_interface>
</interface>
</interface_list>
</vip>
<!-- Software Error Detection Configuration -->
<errd polltimer="10">
<!-- Samsung SSM process -->
<proc name="pg_ctl.exe" atleast="1" action="restart" class="prim" />
<proc name="ServiceManager.exe" atleast="1" action="restart" class="prim" />
<!--
<proc name="HAServerService.exe" atleast="1" action="restart" class="prim"/>
-->
</errd>
<!-- File Replication Configuration -->
<!-- Adapt with the directory of your PostgreSQL database and logs
-->
<rfs async="second" acl="off" nbrei="3">
<replicated dir="C:\PostgreSQL\9.1\data" mode="read_only">
<notreplicated path="pg_log"/>
<notreplicated path="postmaster.pid"/>
</replicated>
<replicated dir="C:\Program Files (x86)\Samsung\SSM\SystemManager\MapFile" mode="read_only"/>
</rfs>
<!-- User scripts activation -->
<user nicestoptimeout="300" forcestoptimeout="300" logging="userlog" />
</service>
</safe>
start_prim.cmd
@echo off
rem Script called on the primary server for starting application services
rem For logging into SafeKit log use:
rem "%SAFE%\safekit" printi | printe "message"
rem stdout goes into Application log
echo "Running start_prim %*"
set res=0
rem TODO: set to manual the start of services when the system boots
net start "postgresql-9.1 - PostgreSQL Server 9.1"
if not %errorlevel% == 0 (
%SAFE%\safekit printi "PostgreSQL (postgresql-9.1 - PostgreSQL Server 9.1) start failed"
goto stop
) else (
%SAFE%\safekit printi "PostgreSQL (postgresql-9.1 - PostgreSQL Server 9.1) started"
)
net start "SSM System Manager"
if not %errorlevel% == 0 (
%SAFE%\safekit printi "SSM System Manager start failed")
goto stop
) else (
%SAFE%\safekit printi "SSM System Manager started"
)
net start "SSM Watch Services Manager"
if not %errorlevel% == 0 (
%SAFE%\safekit printi "SSM Watch Services Manager start failed"
goto stop
) else (
%SAFE%\safekit printi "SSM Watch Services Manager started"
)
rem net start "HA Server Service"
rem if not %errorlevel% == 0 (
rem %SAFE%\safekit printi "HA Server Service start failed"
rem goto stop
rem ) else (
rem %SAFE%\safekit printi "HA Server Service started"
rem )
if %res% == 0 goto end
:stop
set res=%errorlevel%
"%SAFE%\safekit" printe "start_prim failed"
rem uncomment to stop SafeKit when critical
rem "%SAFE%\safekit" stop -i "start_prim"
:end
stop_prim.cmd
@echo off
rem Script called on the primary server for stopping application services
rem For logging into SafeKit log use:
rem "%SAFE%\safekit" printi | printe "message"
rem ----------------------------------------------------------
rem
rem 2 stop modes:
rem
rem - graceful stop
rem call standard application stop with net stop
rem
rem - force stop (%1=force)
rem kill application's processes
rem
rem ----------------------------------------------------------
rem stdout goes into Application log
echo "Running stop_prim %*"
set res=0
rem action on force stop
if "%1" == "force" (
%SAFE%\safekit printi "Force stop: kill processes of Samsung SSM application"
%SAFE%\safekit kill -name="watchservices.exe" -level="terminate"
%SAFE%\safekit kill -name="java.exe" -argregex=".*systemmanager.*" -level="terminate"
%SAFE%\safekit kill -name="pg_ctl.exe" -level="terminate"
%SAFE%\safekit kill -name="postgres.exe" -level="terminate"
%SAFE%\safekit kill -name="HAServerService.exe" -level="terminate"
%SAFE%\safekit kill -name="systemanager.exe" -level="terminate"
goto end
)
rem %SAFE%\safekit printi "Stopping HA Server Service"
rem net stop "HA Server Service"
%SAFE%\safekit printi "Stopping SSM Watch Services Manager"
net stop "SSM Watch Services Manager"
%SAFE%\safekit printi "Stopping SSM System Manager"
net stop "SSM System Manager"
%SAFE%\safekit printi "Stopping PostgreSQL (postgresql-9.1 - PostgreSQL Server 9.1)"
net stop "postgresql-9.1 - PostgreSQL Server 9.1"
del C:\PostgreSQL\9.1\data\postmaster.pid
rem Wait a little for the real stop of services
"%SAFEBIN%\sleep" 10
if %res% == 0 goto end
"%SAFE%\safekit" printe "stop_prim failed"
:end
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The solution includes all clustering features:
server failure monitoring, network failure monitoring, software failure monitoring,
automatic
Hanwha SSM restart with a quick recovery time, a virtual IP address switched in case of failure to automatically reroute clients
This is not the case with replication-only solutions like replication at the database level
