* `max_age` - Sets a maximum time in seconds for browsers to cache CORS responses. Defaults to `600`.

The middleware responds to two particular types of HTTP request...

### CORS preflight requests

These are any `OPTIONS` request with `Origin` and `Access-Control-Request-Method` headers.

* `max_age` - Define um tempo máximo em segundos para os navegadores armazenarem em cache as respostas CORS. O padrão é `600`.

O middleware responde a dois tipos específicos de solicitação HTTP...

### Requisições CORS pré-voo (preflight)

Estas são quaisquer solicitações `OPTIONS` com cabeçalhos `Origin` e `Access-Control-Request-Method`.

- Kubeadm: removed preflight check for existence of the conntrack binary, as conntrack is no longer a kube-proxy dependency in version 1.32 and newer. ([#126953](https://github.com/kubernetes/kubernetes/pull/126953), [@aroradaman](https://github.com/aroradaman)) [SIG Cluster...

- Kubeadm: Added support during the preflight check "CreateJob" of "kubeadm upgrade" to check if there are no nodes where a Pod can be scheduled. If there are none, show a warning and skip this preflight check. This can happen in single node clusters where the only node was drained. ([#124503](https://github.com/kubernetes/kubernetes/pull/124503), [@neolit123](https:/...

- Kubeadm: switch the preflight check (called 'Swap') that verifies if swap is enabled on Linux hosts to report a warning instead of an error. This is related to the graduation of the NodeSwap feature gate in the kubelet to Beta and being enabled by default in 1.23 - allows swap support on Linux hosts. In the next release of kubeadm (1.24) the preflight check will be removed, thus we recommend that you stop using it - e.g. via `--ignore-preflight-errors`...

- Kubeadm: during the preflight check "CreateJob" of "kubeadm upgrade", check if there are no nodes where a Pod can schedule. If there are none, show a warning and skip this preflight check. This can happen in single node clusters where the only node was drained. ([#124570](https://github.com/kubernetes/kubernetes/pull/124570), [@neolit123](https://gi...

                      properties:
                        allowCredentials:
                          description: Indicates whether the caller is allowed to
                            send the actual request (not the preflight) using credentials.
                          nullable: true
                          type: boolean
                        allowHeaders:

proxy_read_timeout flag to kubeapi_load_balancer charm. ([#57926](https://github.com/kubernetes/kubernetes/pull/57926), [@wwwtyro](https://github.com/wwwtyro))

* Check for known manifests during preflight instead of only checking for non-empty manifests directory. This makes the preflight checks less heavy-handed by specifically checking for well-known files (kube-apiserver.yaml, kube-controller-manager.yaml, kube-scheduler.yaml, etcd.yaml) in /etc/kubernetes/manifests instead of simply checking...

### Other (Cleanup or Flake)

- Kubeadm: removed `socat` and `ebtables` from kubeadm preflight checks ([#127415](https://github.com/kubernetes/kubernetes/pull/127415), [@saschagrunert](https://github.com/saschagrunert)) [SIG Cluster Lifecycle]

## Dependencies

### Added
_Nothing has changed._

* kubeadm now produces error during preflight checks if swap is enabled. Users, who can setup kubelet to run in unsupported environment with enabled swap, will be able to skip that preflight check. ([#55399](https://github.com/kubernetes/kubernetes/pull/55399), [@kad](https://github.com/kad))