Xenserver: Adding a server to a Pool

This is going to cover 2 error messages when adding a new / additional Server to a XenServer pool.

1) This server’s hardware is incompatible with the masters.
2) The CPU does not support masking of features. details: CPU does not have FlexMigration

Issue 1)

You want to add a new server to an existing pool or want to merge 2 or more servers to one pool.

This server’s hardware is incompatible with the masters.

This error tries to tell you have most likely have different CPU Hardware on the servers and that it cannot merge them to a pool.

There is a detailed description on why and how https://support.citrix.com/article/CTX127059

You can get the CPU features by running

xe host-cpu-info

See on the below examples how it went out on my 2 boxes.

[root@xenserver00 ~]# xe host-cpu-info
cpu_count : 4
 socket_count: 1
 vendor: GenuineIntel
 speed: 2825.956
 modelname: Intel(R) Core(TM)2 Quad CPU Q9550 @ 2.83GHz
 family: 6
 model: 23
 stepping: 10
 flags: fpu de tsc msr pae mce cx8 apic sep mca cmov pat clflush acpi mmx fxsr sse sse2 ss ht syscall nx lm constant_tsc rep_good nopl pni monitor vmx est ssse3 cx16 sse4_1 hypervisor lahf_lm dtherm tpr_shadow vnmi flexpriority
 features: 0408e3fd-bfebfbff-00000001-20100800
 features_after_reboot: 0408e3fd-bfebfbff-00000001-20100800
 physical_features: 0408e3fd-bfebfbff-00000001-20100800
 maskable: base

[root@xenserver01 ~]# xe host-cpu-info
cpu_count : 4
 socket_count: 1
 vendor: GenuineIntel
 speed: 2660.078
 modelname: Intel(R) Core(TM)2 Quad CPU Q6700 @ 2.66GHz
 family: 6
 model: 15
 stepping: 11
 flags: fpu de tsc msr pae mce cx8 apic sep mca cmov pat clflush acpi mmx fxsr sse sse2 ss ht syscall nx lm constant_tsc rep_good nopl pni monitor vmx est ssse3 cx16 hypervisor lahf_lm dtherm tpr_shadow vnmi flexpriority
 features: 0000e3bd-bfebfbff-00000001-20100800
 features_after_reboot: 0000e3bd-bfebfbff-00000001-20100800
 physical_features: 0000e3bd-bfebfbff-00000001-20100800
 maskable: no

Yeah I have 2 different boxes with 2 different CPU features.

There is a way to mask the features to match them between the boxes.

To do so you will need to get uuid of your hosts. Example

root@xenserver01 ~]# xe host-list
uuid ( RO) : f54a8c38-56f2-4dc4-878c-e8ed3fc36889
 name-label ( RW): xenserver01.local

So I run:

[root@xenserver01 ~]# xe host-set-cpu-features features=0408e3fd-bfebfbff-00000001-20100800 uuid=f54a8c38-56f2-4dc4-878c-e8ed3fc36889
The CPU does not support masking of features.
details: CPU does not have FlexMigration

Naturally I had a 50/50 chance and took the wrong box which lead the to issue Nr 2)

The CPU does not support masking of features.
details: CPU does not have FlexMigration

So to sort issue 2) The CPU does not support masking of features. details: CPU does not have FlexMigration

I run the same command on the other node and apparently that CPU did allow me to apply masking.

[root@xenserver00 ~]# xe host-list
uuid ( RO) : 3f6db05d-bef6-4f9f-a2f3-a01f1786f60d
name-label ( RW): xenserver00.local
name-description ( RW): Default install of XenServer

[root@xenserver00 ~]# xe host-set-cpu-features features=0000e3bd-bfebfbff-00000001-20100800 uuid=3f6db05d-bef6-4f9f-a2f3-a01f1786f60d

You should now be able to join the servers to one pool. If not then you wont get around to get other hardware.