PCNS Vappliance 4.1 and vmware 5.1 shutdown and maintance mode question

[Anonymous user]

Good Day,

Configuration:  Two hosts running Esxi 5.1 with DR (vmotion) enabled.  The hosts are on two UPS that are configured to be redundant (Each hosts has two power supplies and each power supply  is plugged into one of the Two UPS)  vCenter is on one host (Host1)  PCNS vAppliance is on the other host (Host2)

I have been on the phone with vmware and your tech support with question for PCNS and a question arose.  By default vmware will not migrate a VM (guest) that is shutdown if a host goes into maintenance mode.  So lets say that during shutdown all the VM are shutdown leaving only PCNS left on Host2.  PCNS orders Host1 to go into Maintenance mode and then orders itself (Host2) to go into maintenance mode thus shutting itself down.  Just before shutdown Host2 removes itself from maintenance mode so that PCNS will start up when Host2 starts up so it can remove host1 from maintenance mode.

Since the guest were already shutdown, does the guests from host1 migrate to host2? 

Thank You

Adam Raff

[BillP]

Hi,

No. Any VMs that are powered down will not be migrated. 

[Anonymous user]

Hi Bill,

Thank You for the quick follow up and answer.

So with that answer I would like to expand my question a little to see if I understand this correctly now

We have two hosts (host1 and host2) protected by two UPS set to go critical after 20min on battery power.

I believe there is a 180 second delay (3min) when the timer reaches zero then you start the next clock

Virtual Machine shutdown starts which will take 240 seconds (4min)  (this time is not set in stone yet we may have to increases it)

After all VM's shutdown (This would include all of our DNS and DC) vCenter will start to shutdown which will take another 240 seconds (4min)

Since all the DC and DNS are now shutdown, communications will break. the system is setup to run via local accounts from PCNS which are configured on the two hosts and on vCenter

At this time if configured a timer, if set will allow for 240 seconds (4min) for migrations of VM from any hosts that are now going into maintenance mode to migrate to the remaining hosts as PCNS issues the command for vCenter to shutdown.  vCenter issues the command for the hosts to go into maintenance mode (Since all of our VM are in a shutdown state there should be no migrations and PCNS allows Host1 to shutdown and Host2 starts to go into Maintenance mode but is removed as that is where PCNS is installed.  It removes the command and Maintenance mode is lifted but the host2 still shuts down.

UPS do not shutdown or turnoff on our system nor does the VM's start up when power comes back on except for PCNS on Host2.

Once power comes back on we do a controlled startup.   Both hosts start up since host2 has PCNS installed that hosts allows PCNS to startup and it turns off maintenance mode for  Host1 which allows us to start the VM.

Is this correct and or am I missing something.

Thanks

Adam Raff

[BillP]

Hi,

You should read Application Note 180 and the PowerChute Network Shutdown VMware User's Guide. VM migration is discussed starting on page 30 of the user's Guide PDF.

VM migration will take place before VM shutdown.  VMs will not be migrated to Hosts that are powered off, in a disconnected state, in maintenance mode, or affected by a UPS critical event.

On 4/3/2017 2:34 PM, Adam said:

UPS do not shutdown or turnoff on our system nor does the VM's start up when power comes back on except for PCNS on Host2.

Once power comes back on we do a controlled startup.   Both hosts start up since host2 has PCNS installed that hosts allows PCNS to startup and it turns off maintenance mode for  Host1 which allows us to start the VM.

Doing a controlled shutdown of the UPS and start-up is fine. As noted the PCNS VM must be on line to allow for host 1 to be taken out of maintenance mode. If you want to manually start the other VMs that is fine. 

[Anonymous user]

Hi Bill,

After reading Pg 30 under VM Migration without DRS, it appears that there is no way to prevent the VM's from migration to another host using PCNS as you implied on your earlier post.  PCNS does the migration first then a shutdown. 

Why?  Is there a reason that you do not allow a shutdown first for those system that just need to shutdown and no need to migrate to another host.  I am just trying to understand the technical reasons why this can't be accomplished.  I have seen other users bring this up but have not noticed an answers as to why PCNS does it this way.

Note: I do understand that the last host standing will be the host that has PCNS on it (in our case Host2) as that host will shut down but PCNS will remove the Maintenance mode before final shutdown as discussed in the NOTE #180 Page 5 

Thank You

Adam Raff

[BillP]

Hi,

I'm sorry but I'm not sure what you are seeing on page 30 of the PDF. I reread it and it states VMs will not be migrated to Hosts that are in maintenance mode. When the shutdown process is started PCNS puts the hosts into maintenance mode so the VMs will not be migrated to those hosts. If there is a host or host in the cluster that is not part of the shutdown then the VMs will be migrated.

Virtual Machine Migration

If you enable Virtual Machine migration, use the Duration field to set the time allowed for the VMs to migrate to another healthy Host in the Cluster. VMs will not be migrated to Hosts that are powered off, in a disconnected state, in maintenance mode, or affected by a UPS critical event.

Custom Target Host Migration

By default, PowerChute will migrate VMs to any available Host in the same cluster. To control where VMs get migrated to, enable the Select target host for Migration option in the Virtualization Settings page of the PowerChute Setup or on the Virtualization Settings page in the main UI.

When the shutdown process is started PCNS puts the hosts into maintenance mode so the VMs will not be migrated to those hosts. If there is a host or host in the cluster that is not part of the shutdown then the VMs will be migrated to those hosts.

[Anonymous user]

Hi Bill,

Per your previous post "VM migration will take place before VM shutdown."  

Assume the following

5min for migration

5min to shut down all VM

20min of time when critical sounds

If a critical alert due to power failure happens the power drains from the UPS until 20min is left at that time it alerts PCNS that it needs to start shutting down the VM's and the hosts and starts the shutdown process.  The system will wait 2min which is the default waiting period.  This is where it gets kind of muggy

We have two hosts Host1 and host2, since what you say above (VM migrations will take place before VM shutdown) the system will put host1 in maintenance mode all VM will be migrated to host2. Since host1 is going into maintenance mode it will force all VM's off and move them to host2 so you have to migrate them  given the time for migration 5min when completed it wait another 2min.  Host1 is now in maintenance and the command is given to power down all VM which are now on Host2 which in this case is 5min after said time elapse another 2min is added then the PCNS puts Host2 in maintenance mode orders both hosts to shut down but removes host2 from maintenance mode just before shutdown.

So what i am trying to find out is this.  If you do not set a time for migration and leave it blank so there is no migration but set the timing to power down all servers.  Then when the host goes into maintenance mode it will not migrate the down VM.  As I do not want the VM's to migrate from host1 to host2.

Is there a reason why I would want to migrate the VM's so that they are on host2 when I start up?

Thank You

Adam Raff

[BillP]

Hi,

On 4/5/2017 5:23 PM, Adam said:

So what i am trying to find out is this.  If you do not set a time for migration and leave it blank so there is no migration but set the timing to power down all servers.  Then when the host goes into maintenance mode it will not migrate the down VM.  As I do not want the VM's to migrate from host1 to host2.

If you do not select migration as an option then the VMs will not be migrated. If you have selected DRS and set it to automatic then you should select migration in PCNS to allow the VMs to be migrated prior to power down. 

I ran a test today and the results are in the screenshot below. PCNS was configured with 2 hosts and was running on host .22. vCenter was running on a third host that was not part of the shutdown process and PCNS was configured to start the shutdown process after the UPS had been on battery for 2 minutes. When the UPS switched to battery PCNS waited the 2 minutes and started the shutdown process by putting the hosts into maintenance mode. Since there were no suitable hosts available none of the VMs were migrated. PCNS did wait the 2 minute delay for the migration to take place even though none were migrated and then started shutting down the VMs. 

I hope this helps.

[Anonymous user]

Bill I am so sorry for the delay in this response and thank you for testing this out.  I was busy trying to get another UPS in place so I can start this project.  From your demonstration I see the PCN was not installed as a VM and not part of the host configuration.  Since on our setup the PCN is a VM on host2 Will that effect or change the out put of this scenario?

Thanks so much

Adam Raff

[BillP]

Hi,

In the test I ran PCNS was running as a VM on host 10.218.44.22 

[Anonymous user]

Bill I am sorry I misread your previous reply

vCenter was running on a third host that was not part of the shutdown process and PCNS was configured to start the shutdown process after the UPS had been on battery for 2 minutes. 

My Bad, vCenter was not part of the of the hosts.

So my new question is this.  vCenter on my setup is on host1 and PCNS is on host2.  Will this scenario still work out or does that change things. 

thanks again for your patience.

Adam Raff

[BillP]

Hi,

Having vCenter Server running on a VM that is part of the host cluster is not an issue. you can have PCNS runing on 1 host and vCenter running on another host. Just be sure when configuring to check the box when asked if vCenter is running on a VM. See page 16 of the User's Guide http://www.apc.com/salestools/PMAR-9DNLQK/PMAR-9DNLQK_R3_EN.pdf?sdirect=true

Also, make sure the proper host is marked with the vCenter Sever icon. See page 18 of the Use's Guide. http://www.apc.com/salestools/PMAR-9DNLQK/PMAR-9DNLQK_R3_EN.pdf?sdirect=true

In the example on page 18 of the User's Guide both PCNS and vCenter are running on a single host. 

[Anonymous user]

Yep all that has been configured and shows up fine,  I am using a local account on both the hosts and on vCenter for shut down as my DC are VMs.  Everything appears to check out fine.  I have I hope one last question.

Since I am setting up the UPS's (I have two running UPS's in Redundant configuration)

 UPS 1 has a run time for 1hr and 46min and I set the Low battery duration for 20min

 UPS 2 has a run time for 3hr and 2min and I set the low battery duration for 20min

I am not sure how this may work as the run time is so different between them.  Will this be an issue?

[BillP · Accepted solution]

Hi,

What will happen is when the first unit hits low battery it will be ignored so when the second UPS hits low battery the shutdown will begin. 

NOTE: PowerChute Network Shutdown considers all UPS devices in a Redundant configuration as one UPS System. Each
UPS must be able to support the entire load itself. If the UPS cannot handle the entire load by itself then you need to change the shutdown parameters so that both UPS signal critical event  at the same time. See the User's Guide for more information http://www.apc.com/salestools/PMAR-9DNLQK/PMAR-9DNLQK_R3_EN.pdf?sdirect=true Page 119.