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Nutanix Employee

Acropolis Virtual Machine High Availability Resources

 

Since the release of Acropolis 4.5 there have been some great community posts and videos on VM high availability resources that I wanted to gather in one place.  I think the key difference between competing hypervisors is the fact that our management layer is built to be highly available. Having the ability to always know the underlying resources gives AHV an advantage on making sure your resources are used wisely with management overhead.  The following resources talk about HA and how to configure it in your environment.

 

Acropolis Virtual Machine High Availability – Part I

 

Acropolis Virtual Machine High Availability – Part II

 

MongoDB with HA

 

3 Comments
Adventurer

Thank you so much for puting this together. I was looking for details on how to configure the different modes of HA. It's not detailed in the Web Console guide... I can see now this can only be done through acli.

 

Is there an acli reference guide anywhere ? I'm unable to find it.

Nutanix Employee

Hi @Superkikim

 

Will this help?

 

HA per VM

https://portal.nutanix.com/#/page/docs/details?targetId=AMF_Guide-Acr_v4_6:man_acli_ha_auto_r.html

 

HA at the host level

https://portal.nutanix.com/#/page/docs/details?targetId=AMF_Guide-Acr_v4_5:man_acli_ha_auto_r.html

 

example

 

By default, AHV has two HA schemes that are selected automatically once you enable HA from Prism

  • kAcropolisHAReserveSegments and
  • kReservedForHAFailover

In the first scheme, all hosts in the cluster are scheduleable but in the second scheme, a host is marked reserved for failover capacity and does not allow Virtual Machines to be run/powered on or migrated to the node

This KB shows you how to change the HA policy using ACLI

 

Solution

For AHV HA, there are two HA schemes

For the schemes, a host.get will show the below

<acropolis> host.list
Hypervisor address Host UUID Schedulable
10.180.106.54 6eb54585-fc3b-4456-8938-0c81d8a3592e False
10.180.106.55 6c696f3d-9932-42c2-b897-257b27864052 True
10.180.106.56 e302d0b8-8649-4fcd-9aa6-b7c15d657222 True

<acropolis> host.get 6eb54585-fc3b-4456-8938-0c81d8a3592e
10.180.106.54 {
cpu_usage_ppm: 15732
cvm_cpu_usage_ppm: 8333
cvm_memory_size_bytes: 34359738368
cvm_num_vcpus: 8
cvm_uuid: "8028461d-a002-47e4-8fa4-fc8b46983db2"
logical_timestamp: 69312
mem_segment_size_bytes: 0
mem_usage_bytes: 35079061504
memory_size_bytes: 270306115584
node_state: "kReservedForHAFailover"
num_assigned_mem_segments: 0
num_cpus: 48
num_reserved_mem_segments: 0
schedulable: False
uuid: "6eb54585-fc3b-4456-8938-0c81d8a3592e"

For the second scheme, the result will be as below:


<acropolis> host.list
Hypervisor address Host UUID Schedulable
10.180.106.54 6eb54585-fc3b-4456-8938-0c81d8a3592e True
10.180.106.55 6c696f3d-9932-42c2-b897-257b27864052 True
10.180.106.56 e302d0b8-8649-4fcd-9aa6-b7c15d657222 True

<acropolis> host.get 6eb54585-fc3b-4456-8938-0c81d8a3592e
10.180.106.54 {
cpu_usage_ppm: 15732
cvm_cpu_usage_ppm: 8333
cvm_memory_size_bytes: 34359738368
cvm_num_vcpus: 8
cvm_uuid: "8028461d-a002-47e4-8fa4-fc8b46983db2"
logical_timestamp: 69312
mem_segment_size_bytes: 0
mem_usage_bytes: 35079061504
memory_size_bytes: 270306115584
node_state: "
kAcropolisHAReserveSegments"
num_assigned_mem_segments: 0
num_cpus: 48
num_reserved_mem_segments: 0
schedulable: True
uuid: "6eb54585-fc3b-4456-8938-0c81d8a3592e"


To change the reservation type, use the below command


<acropolis> ha.update enable_failover=true num_host_failures_to_tolerate=1 reservation_type=kAcropolisHAReserveSegments
HaUpdate: complete

Adventurer

Thank you. FOr instance, I was looking for that globally: https://portal.nutanix.com/#/page/docs/details?targetId=AMF_Guide-Acr_v4_5:man_acli_c.html Smiley Happy

 

That's great.

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