Like most of my blog posts, this topic was also a question which was raised by one of my customer during an SRM Plan & Design engagement. I did not find a blog or a document which speaks about this topic and hence I thought of documenting this on vXpress and help the community use this solution if they face a similar situation.
Well, the topic is pretty much self explanatory, however let me go ahead and dissect it for those who are wondering what is TEST Network with respect to SRM.
The most popular feature of VMware SRM is that, it allows you to perform DR drills, using the Test Recovery option which allows you to Test your DR side Virtual Machines, Applications, Networks and the Workflows which you define in the Recovery Plans. These Recovery Plans are created during the configuration of SRM and they are modern day DR Run-books which execute as soon as you run a Test Recovery of Actual Recovery from the SRM Console. Lets look at the difference between the TEST & RECOVERY highlighted in RED in the screenshot below:-
Once you have created a Recovery Plan, which defines the workflow which need to be executed when you press either of those buttons, you are ready to either perform a
a) Test Drill - Just a test of your DR site virtual machines, to see if your DR solution is actually working. In this process, the Production Virtual Machines keep running on the Primary Site, while copy of these machines in the DR side are mounted on the ESXi servers and are powered on in a snapshot mode (This snapshot is deleted when you cleanup test recovery, so that you do not save any changes on the DR VM's while testing). The replication of data whether Storage Based of vSphere Replication (host based) is not impacted with this Test Drill at any time.
b) Recovery - This button if used, means you actually had a bad day at office... It means you met a disaster, and finally decided that your production site is Down (due to a fire, power outage, earthquake, floods etc). Once you press this button and agree to the warnings, you force the DR machines to power on based on your Recovery Plan and start operations from your DR Site.
Now there is a minor difference in both the cases. In case of Recovery your primary VM's are down, hence you power on your secondary VM's to continue business operations. The Secondary Site network can be an extended network from the Primary site or can be a different sub-net as well. You would not have duplicate Host Names or IP issues since the primary machines are DOWN.
In case of the Test Drill, since the Primary machines are still UP, you power on the DR machines in a ISOLATED TEST NETWORK. This can be created either by choosing the AUTO option while defining DR and Test Networks in the Recovery Plan or by provisioning an ISOLATED VLAN with IP addresses which can be assigned to these test machines and Testing can be performed.
So far I hope it was easy to understand and implement...
Now,since the product has this capability of Test DR Drills, you would want to Test your Recovery Plans, which include, Virtual Machines, Operating Systems, Data, VM Interoperatbility etc, which can be powered on in a bubble environment and tested as and when needed. This can be done even when your production is up and running so this is COOL. However, you need to understand that this testing needs that all the elements which you need to perform a test should be a part of this ISOLATED network, hence anything outside this network cannot be tested or included in this trust zone to avoid DNS conflicts which could lead to data loss/corruption etc. For eg. If you are testing a 3 tier application which has a Web VM which is virtualized and protected via SRM, an application VM (virtualized and protected via SRM), and a database which is PHYSICAL and is not protected via SRM, then you cannot really test the application completely as the physical database cannot run in the Test Mode like VMware Virtual Machines.
Even if you have the capability in your database to run on a snapshot mode, it is not recommended to include that DB in your Test environment unless you are changing the DB networking to the isolated Test Network. Do not create any routes between your Test network and LAN as this can cause trouble which is irreparable.
Phewwww.... Alright, now since you would follow the right rules, lets talk about accessing this test network. Lets say you are capable to test these Applications, VM instances etc and you want your testers to access this environment from your Primary Site (in most of the cases here is where the application teams, users etc would be sitting). You have a couple of options here:-
a) Jumpstart Terminal Server - You can provision a W2K8 R2 VM on the DR site with RDS ( aka termial server) license and allow your testers to access this machine and use the web browser to access the application. This VM can be used without a Terminal Server License if you do not want multiple Testers to access this VM via RDP. This VM would be provisioned with 2 vNics. One connected to your TEST Network Isolated port Group and the other to your DR Site LAN. Needless to say that your Primary site users should have access to the secondary site LAN via MPLS cloud etc.
b) VMware View Desktops - VDI is another way of making this possible, since you can provision desktops in this network PG and ensure that you create a seperate pool for DR testers and allow them to connect when needed.
c) vSphere Client Access - You can allow the Testers to Login to the DR site vCenter with limited access and then can directly launch the console of the Test Virtual Machines and play around. This should be very well planned and tested to avoid any unauthorized access.
d) VMRC Weblink - You can generate a Virtual Machine Remote Console weblink and give them to the Testers to use in case they need to, however this will also give them direct access to the virtual machine files and data which you may or may not want to share.
I am sure you can think of other ways as well, but remember that you think and freeze a method during the planning phase to ensure that you can test your deployment in a pilot before going live in the production environment.
Here are a few screenshots from a PPT which I prepared for explaining this scenario.
SRM Setup between Primary & DR Site using vSphere Replication of Storage Array Based Replication
Performing a Test Recovery which will continue the Storage Replication and Bring the DR Machines up in a Test Network in a Snapshot Mode
The Primary Site has gone down and the Recovery is executed. The business has failed over to the DR Site and the Virtual Machines are connected to the DR Network
Well, I know this might bring up more questions in your mind and if it does then feel free to use the comment column and I will be happy to discuss these options. Choose the best for your DR environment and I can ensure that you would never face any issues whatsoever.