As part of the larger plan to drop --cloud-provider and --cloud-config
from kube-apiserver, we need to stop calling Cloud Provider API to
find the external ip address when one is not specified on the command
line.
When ExternalHost is not specified, we check if AdvertiseAddress is
specified and use that, if that is missing then we use os.Hostname().
When testing this feature, found a problem that when ExternalHost
is specified, the port was not added in the generated URL. So fixed
that as well.
Long term plan is to remove all uses of cloud provider from kube api
server. As part of that, we need to remove the dependency on
figuring out the host address of the node running the kube api server
using the cloud provider. In this review, we log a warning that this
feature that is usually used for example with swagger generation
will go away in the future.
If we set --external-hostname, then the api server does not look
in the CloudProviderOptions.DefaultExternalHost method. While we
are at it, let's log an info message, so if there is a failure
the operator gets a hint that they can use --external-hostname
to bypass the lookup in the cloud provider. This will enable us
to set the CLOUD_PROVIDER to openstack for example and not have to
really run api server inside a openstack vm.
Automatic merge from submit-queue (batch tested with PRs 47038, 47105)
extending DefaultExternalHost for any registred cloud provider
**What this PR does / why we need it**: this PR enables DefaultExternalHost to work with any registered cloud provider.
**Which issue this PR fixes** : fixes#46567
**Special notes for your reviewer**:
**Release note**:
```release-note
When determining the default external host of the kube apiserver, any configured cloud provider is now consulted
```
Davanum Srinivas