- Kubeadm: Fixed a preflight check that could fail hostname construction in IPv6 setups. ([#134588](https://github.com/kubernetes/kubernetes/pull/134588), [@liggitt](https://github.com/liggitt)) [SIG API Machinery, Auth, Cloud Provider, Cluster Lifecycle and Testing]

# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
#
# setup.python.sh: Install a specific Python version and packages for it.
# Usage: setup.python.sh <pyversion> <requirements.txt>
set -xe

source ~/.bashrc
VERSION=$1
REQUIREMENTS=$2

# Install Python packages for this container's version

# limitations under the License.
# ==============================================================================
#
# setup.packages.sh: Given a list of Ubuntu packages, install them and clean up.
# Usage: setup.packages.sh <package_list.txt>
set -e

# Prevent apt install tzinfo from asking our location (assumes UTC)
export DEBIAN_FRONTEND=noninteractive

apt-get update

Kubeadm: during "init" an empty cgroupDriver value in the KubeletConfiguration is now always set to "systemd" unless the user is explicit about it. This requires existing machine setups to configure the container runtime to use the "systemd" driver. Documentation on this topic can be found here: https://kubernetes.io/docs/setup/production-environment/container-runtimes/. When upgrading existing clusters / nodes using "kubeadm upgrade" the old cgroupDriver value is preserved, but in 1.22 this change will...

```

- Kubernetes components no longer handle panics, and instead actively crash.  All Kubernetes components should be run by something that actively restarts them. This is true of the default setups, but those with custom environments may need to double-check (#28800, @lavalamp)
- kubelet now defaults to `--cloud-provider=auto-detect`, use `--cloud-provider=''` to preserve previous default of no cloud provider (#28258, @vishh)

- Kubeadm: fixes a preflight check that can fail hostname construction in IPV6 setups ([#134592](https://github.com/kubernetes/kubernetes/pull/134592), [@liggitt](https://github.com/liggitt)) [SIG API Machinery, Auth, Cloud Provider, Cluster Lifecycle and Testing]

### Other (Cleanup or Flake)

# Security - First Steps { #security-first-steps }

Let's imagine that you have your **backend** API in some domain.

And you have a **frontend** in another domain or in a different path of the same domain (or in a mobile application).

And you want to have a way for the frontend to authenticate with the backend, using a **username** and **password**.

We can use **OAuth2** to build that with **FastAPI**.

# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
#
# Sets up custom apt sources for our TF images.

# Prevent apt install tzinfo from asking our location (assumes UTC)
export DEBIAN_FRONTEND=noninteractive

# Set up shared custom sources
apt-get update

    return CartesianSet.create(sets);
  }

  /**
   * Returns every possible list that can be formed by choosing one element from each of the given
   * sets in order; the "n-ary <a href="http://en.wikipedia.org/wiki/Cartesian_product">Cartesian
   * product</a>" of the sets. For example:
   *
   * {@snippet :
   * Sets.cartesianProduct(

- Kubeadm: increase robustness for "kubeadm join" when adding etcd members on slower setups ([#90645](https://github.com/kubernetes/kubernetes/pull/90645), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]