While Microsoft has undoubtedly been catching up, and there are always some specific products where one vendor has a leg up, there is no doubt the Azure cloud has been technologically far behind AWS and significantly behind Google.
First of all, I'd want to acknowledge that Google is behind AWS as well. One big technical reason is IAM. Few realize just how important AWS IAM is as a service federation infrastructure. If you look at the details, Google's IAM product is inferior.
Now, on to Azure. Three years ago I was involved with a high stakes effort to port an AWS-grown platform service architecture onto Azure. At the time, they had massive gaps in their understanding of what IaaS meant. Here are some concrete examples:
* They did not really understand what object storage was. Blob storage was not possible to use at scale due to trivially low bandwidth, storage, and API limits
* Software-defined networking was not available between availability zones
* Software-defined networking could not be used to launch mixes of instance types
* Software-defined Internet gateways were not available except in a config that resembled "AWS Classic" networking
* On-demand instances were effectively unavailable beyond one or two instances at a time (at least for the instance types we wanted). You had to reserve instance capacity in advance, by going through a support ticket
* Creating and using custom machine images was undocumented in the API
* Instance metadata APIs were not available
* On-demand instance launches would encounter weird behaviors, where upon hitting certain limits entire groups of instances would be terminated
* Many aspects of APIs for the above were undocumented and unsupported
Combined, these problems made deployment on Azure extremely difficult. I have prefaced this with the caveat that Microsoft has improved since then. Many of the problems above are no longer issues, I'm sure. But what I found was a gaping chasm between what Microsoft claimed and what was really possible on the ground. What I found since then is that Google and Microsoft are making an earnest effort to catch up, and that's good for us consumers, but Microsoft (and to some extent Google) often don't even understand the full feature set of what they are trying to catch up with.
First of all, I'd want to acknowledge that Google is behind AWS as well. One big technical reason is IAM. Few realize just how important AWS IAM is as a service federation infrastructure. If you look at the details, Google's IAM product is inferior.
Now, on to Azure. Three years ago I was involved with a high stakes effort to port an AWS-grown platform service architecture onto Azure. At the time, they had massive gaps in their understanding of what IaaS meant. Here are some concrete examples:
* They did not really understand what object storage was. Blob storage was not possible to use at scale due to trivially low bandwidth, storage, and API limits
* Software-defined networking was not available between availability zones
* Software-defined networking could not be used to launch mixes of instance types
* Software-defined Internet gateways were not available except in a config that resembled "AWS Classic" networking
* On-demand instances were effectively unavailable beyond one or two instances at a time (at least for the instance types we wanted). You had to reserve instance capacity in advance, by going through a support ticket
* Creating and using custom machine images was undocumented in the API
* Instance metadata APIs were not available
* On-demand instance launches would encounter weird behaviors, where upon hitting certain limits entire groups of instances would be terminated
* Many aspects of APIs for the above were undocumented and unsupported
Combined, these problems made deployment on Azure extremely difficult. I have prefaced this with the caveat that Microsoft has improved since then. Many of the problems above are no longer issues, I'm sure. But what I found was a gaping chasm between what Microsoft claimed and what was really possible on the ground. What I found since then is that Google and Microsoft are making an earnest effort to catch up, and that's good for us consumers, but Microsoft (and to some extent Google) often don't even understand the full feature set of what they are trying to catch up with.