The error means the specified VM is not available for a subscription in the specified location.
az aks create \
--resource-group rg-aks-demo \
--location southindia \
--name aks-demo-cluster \
--node-count 1 \
--node-vm-size Standard_D2s_v7 \
--tier free \
--vm-set-type VirtualMachineScaleSets \
--load-balancer-sku standard \
--enable-managed-identity \
--network-plugin azure \
--no-ssh-key \
--attach-acr acrdemoregistry
(VMSizeNotSupported) Virtual Machine size: 'Standard_D2s_v7' is not supported for subscription 00000000-0000-0000-0000-000000000000 in location 'southindia'. The available VM sizes are 'standard_a2_v2,standard_b2s,standard_d2_v5,standard_d2s_v6,standard_e2s_v5,standard_f2s_v2,standard_l2s_v4,standard_nc4as_t4_v3'. [Additional VM sizes redacted for brevity.] Please refer to aka.ms/aks/vm-size-selector to find supported VM sizes in location 'southindia'.
Code: VMSizeNotSupported
Message: Virtual Machine size: 'Standard_D2s_v7' is not supported for subscription 00000000-0000-0000-0000-000000000000 in location 'southindia'. The available VM sizes are 'standard_a2_v2,standard_b2s,standard_d2_v5,standard_d2s_v6,standard_e2s_v5,standard_f2s_v2,standard_l2s_v4,standard_nc4as_t4_v3'. [Additional VM sizes redacted for brevity.] Please refer to aka.ms/aks/vm-size-selector to find supported VM sizes in location 'southindia'.This is verified when listing VM SKUS:
az aks list-vm-skus \
--location southindia \
--size Standard_D2s_v7 \
--all \
--output jsonc
[]To list the available VM sizes available in the location
az aks list-vm-skus \
--location southindia \
--query "[0:10].{
Size:name,
Family:family,
vCPUs:capabilities[?name=='vCPUs'].value | [0],
MemoryGB:capabilities[?name=='MemoryGB'].value | [0]
}" \
--output table
Size Family VCPUs MemoryGB
-------------------- ------------------------------ ------- ----------
Standard_D8_v3 standardDv3Family 8 32
Standard_D5_v2 standardDv2Family 16 56
Standard_NC8as_T4_v3 Standard NCASv3_T4 Family 8 56
Standard_M96s_1_v3 standardMSMediumMemoryv3Family 96 974
Standard_D2als_v6 standardDalv6Family 2 4
Standard_DC24s_v3 standardDCSv3Family 24 192
Standard_FX4ms_v2 StandardFXmsv2Family 4 84
Standard_E32s_v4 standardESv4Family 32 256
Standard_E32ds_v5 standardEDSv5Family 32 256
Standard_D64as_v6 standardDav6Family 64 256