Dears
My Current environment is
3 Esxi 5.5 Hosts with HA enabled
Requirement ;
I have prepared 2 Windows 2012 R2 vm's and I need to build a two node SQL cluster on these. (with WFCS) and I was reading the below article for the supported option and found out that I need to to enable anti affinity rules
VMware KB: Microsoft Clustering on VMware vSphere: Guidelines for supported configurations
I got confused and lost on how to enable these options on HA only clusters,
appreciate if somebody could share their experience in this regard,
DRS requires vSphere Enterprise license. That is the reason it is not showing these options in your environment. vSPhere HA requires vSphere Standard edition. As you have standard edition, you are able to configure HA.
There is NO as such impact.
1. You are using MSCS as cluster of VMs & if anything happens to clustering application configured, MSCS will failover to other VM in MSCS cluster. (I am assuming you are using CIB config. Cluster in Box)
2. vSphere HA helps you to give additional level of HA on host/VM level. As you are running your MSCS cluster VMs on the top of hosts. vSPhere HA is additional HA.
3. In case, host fails, vSphere HA will failover all MSCS clustered VMs to other available host inside vSphere HA cluster. i.e It will restart all VMs on other host. Please note that restarting a VM will have minimal downtime. In this case, as all VMs are on same host, even MSCS cluster will have same downtime as vSphere HA will have. But if you are using CAB (Cluster across box ) as MSCS configuration, you can minimize MSCS VMs downtime.
4. In case, VM itself fails (not host), vSphere HA will restart the failed VM on the same host. In this case MSCS will failover all your application on other VMs in MSCS cluster.
You have only vSPhere HA without DRS. It should be fine. Just that DRS gives some more flexibility to you.
Please note that in any HA solution, in case of failure, you will come across minimal downtime (time may differ across different HA solution).
Have you enabled DRS in your cluster ?
Here is how to configure a VM-VM affinity rule: Create a VM-VM Affinity Rule in the vSphere Web Client
To read more about DRS rules, chek: VMware DRS Rules | Afininty and Anti-Affinity
Dear Richardson
Thanks for the reply.
My environment is HA only cluster (ESXi Standard Edition) in this case how could I achieve my goal?
Best regards
As Richardson specified : You need to enable DRS to configure affinity rules. Once you enable DRS. You can refer below steps to configure anti-affinity rules.
Procedure
Say, you selected 2 VMs in step 8, it is mean that these 2 VMs will not be on same host.
Also vCenter 5.5 has introduced one advanced option ::::
in order to make VM-VM anti-affinity rule vSphere HA aware, you will have to configure one HA advanced option “das.respectVmVmAntiAffinityRules” to true. (default value of this advanced option is false). I repeat this is a HA advanced option, not the DRS advanced option. You can configure this option from web client through this workflow (Cluster>>Manage>>vSphere HA>>Advanced option). However, you can configure this option from Desktop client as well.
It is also important to note that, even when DRS is disabled on cluster, HA continues to honor above rule. As per the current design, we can not disable these rules when DRS is disabled. Hence care must be taken while disabling DRS, you can disable this rule when you disable DRS or when you want to disable this rule, enable DRS for a while in conservative migration threshold mode & disable this rule.
Recently I had written one blog on this as below.
Refer:is vSphere HA aware of DRS affinity rules? | vThinkBeyondVM
I assume, you do not have vCenter server. In order to leverage DRS, you need to have vCenter. It is must. Without vCenter we can not set DRS affinity rules.
I think, you are just using MSCS clustering on host level. (Cluster in Box or Cluster across box). Even in order to manage/configure vSphere HA (cluster of EsXi hosts), you need to have vCenter server.
Dear Vicky
Thanks for the reply.
Does it mean that I cannot configure AntiAfffinity / Affinity rules on HA only Cluster? as I dont see these options in my configuration.
If it Yes what will happen to the SQL VM's Clustered with Shared disk (RDM) during a Host failover ?
please confirm below queries.
are you using MSCS (Microsoft clustering service) solution or similar clustering solution from any other Vendor?
do you have vCenter server installed? (vCenter is primarily used to manage multiple ESXi host in single window and enabling several cool features)
As I said earlier, without vCenter, you can not configure affinity rules. in order to provide HA in case of host (ESXI) failure, you need to have vCenter initially to configure vSphere HA.
Dear Vicky
Please see the reply below
are you using MSCS (Microsoft clustering service) solution or similar clustering solution from any other Vendor?
Yes I am using MSCS within the SQL Guest VM with RDM disks
do you have vCenter server installed? (vCenter is primarily used to manage multiple ESXi host in single window and enabling several cool features)
Yes , I do.
As I said earlier, without vCenter, you can not configure affinity rules. in order to provide HA in case of host (ESXI) failure, you need to have vCenter initially to configure vSphere HA.
Yes I have configured HA , My confusion started when I read the section
Would like to know what will happen if we configure HA only cluster in my environment will it be supported , and will it have any impact on my cluster behaviour?
Best regards
Muralee
DRS requires vSphere Enterprise license. That is the reason it is not showing these options in your environment. vSPhere HA requires vSphere Standard edition. As you have standard edition, you are able to configure HA.
There is NO as such impact.
1. You are using MSCS as cluster of VMs & if anything happens to clustering application configured, MSCS will failover to other VM in MSCS cluster. (I am assuming you are using CIB config. Cluster in Box)
2. vSphere HA helps you to give additional level of HA on host/VM level. As you are running your MSCS cluster VMs on the top of hosts. vSPhere HA is additional HA.
3. In case, host fails, vSphere HA will failover all MSCS clustered VMs to other available host inside vSphere HA cluster. i.e It will restart all VMs on other host. Please note that restarting a VM will have minimal downtime. In this case, as all VMs are on same host, even MSCS cluster will have same downtime as vSphere HA will have. But if you are using CAB (Cluster across box ) as MSCS configuration, you can minimize MSCS VMs downtime.
4. In case, VM itself fails (not host), vSphere HA will restart the failed VM on the same host. In this case MSCS will failover all your application on other VMs in MSCS cluster.
You have only vSPhere HA without DRS. It should be fine. Just that DRS gives some more flexibility to you.
Please note that in any HA solution, in case of failure, you will come across minimal downtime (time may differ across different HA solution).
Dear Vicky
Thanks for the excellent reply.
It certainly cleared all my doubts.
I have one last query which is If I enable DRS (with proper ESXi license) then I need to enabled Affinity /Anti Affinity rules is it correct?
Also what does it mean by
Also vCenter 5.5 has introduced one advanced option ::::
in order to make VM-VM anti-affinity rule vSphere HA aware, you will have to configure one HA advanced option “das.respectVmVmAntiAffinityRules” to true. (default value of this advanced option is false). I repeat this is a HA advanced option, not the DRS advanced option. You can configure this option from web client through this workflow (Cluster>>Manage>>vSphere HA>>Advanced option). However, you can configure this option from Desktop client as well.
Is it mean that this will be configured when we enable HA and DRS?
muralee29477 wrote:
I have one last query which is If I enable DRS (with proper ESXi license) then I need to enabled Affinity /Anti Affinity rules is it correct?
It is not required to configure affinity/anti-affinity rules when DRS is enabled as well. It is all depend on your requirement, what exactly you want to achieve by configuring these rules.
Let me give some details on these rules.
Below are the 4 DRS rules, you can configure.
Here are the current DRS rules we can configure on the DRS cluster:
1. VM-VM affinity rule: This rule is intended to keep group of VMs together on single host.
2. VM-VM anti-affinity rule: This rule is intended to keep group of VMs away from each other all the time.
3. VM-Host affinity rule: This rule restricts to run a group of VMs on a group of Host. This rule can be hard/must or soft/should rule.
4. VM-Host anti-affinity rule: This rule does not allow to run a group of VMs on a group of Host. This rule can be hard/must or soft/should rule.
Now based on above rule details, you can choose any rule and configure that if that makes sense to your environment along with MSCS and vSphere HA.
One example: rule number 2 (VM-VM anti-affinity) can be configured if you have 2 VMs on same host, say that host failed, both VMs will be down (or will be restarted on other host if vSphere HA is there). To avoid downtime for both VMs, you can configure VM-VM anti-affinity rule so that DRS will try its best to keep these VMs on separate host so that in case of failure only one VM will have downtime.
On another query on das.respectVmVmAntiAffinityRules:::: Please read my blog :is vSphere HA aware of DRS affinity rules? | vThinkBeyondVM
