There is currently no way to differentiate Windows instances from Linux
ones. This is needed when you have a mix of node_exporters /
wmi_exporters for OS-level metrics and you want to have them in separate
scrape jobs.
This change allows you to do just that. Example:
```
- job_name: 'node'
azure_sd_configs:
- <azure_sd_config>
relabel_configs:
- source_labels: [__meta_azure_machine_os_type]
regex: Linux
action: keep
```
The way the vendor'd AzureSDK provides to get the OsType is a bit
awkward - as far as I can tell, this information can only be gotten from
the startup disk. Newer versions of the SDK appear to improve this a
bit (by having OS information in the InstanceView), but the current way
still works.
As discussed generally consider SDs as unstable, as realistically they
are never going to be. Drop the words "experimental/beta" from most
places in the docs, as users are getting the wrong impression from this.
For special remote read endpoints which have only data for specific
queries, it is desired to limit the number of queries sent to the
configured remote read endpoint to reduce latency and performance
overhead.
