add a blog to introduce about kubeadm v1beta4

content/en/blog/_posts/2024-08-23-kubeadm-v1beta4.md

@@ -0,0 +1,104 @@
+---
+layout: blog
+title: 'Kubernetes v1.31: kubeadm v1beta4'
+date: 2024-08-23
+slug: kubernetes-1-31-kubeadm-v1beta4
+author: >
+   Paco Xu (DaoCloud)
+---
+
+As part of the Kubernetes v1.31 release, [`kubeadm`](/docs/reference/setup-tools/kubeadm/) is
+adopting a new ([v1beta4](/docs/reference/config-api/kubeadm-config.v1beta4/)) version of
+its configuration file format. Configuration in the previous v1beta3 format is now formally
+deprecated, which means it's supported but you should migrate to v1beta4 and stop using
+the deprecated format.
+Support for v1beta3 configuration will be removed after a minimum of 3 Kubernetes minor releases.
+
+In this article, I'll walk you through key changes;
+I'll explain about the kubeadm v1beta4 configuration format,
+and how to migrate from v1beta3 to v1beta4.
+
+You can read the reference for the v1beta4 configuration format:
+[kubeadm Configuration (v1beta4)]((/docs/reference/config-api/kubeadm-config.v1beta4/)).
+
+### A list of changes since v1beta3
+
+This version improves on the [v1beta3](/docs/reference/config-api/kubeadm-config.v1beta3/)
+format by fixing some minor issues and adding a few new fields.
+
+To put it simply,
+
+- Two new configuration elements: ResetConfiguration and UpgradeConfiguration
+- For InitConfiguration and JoinConfiguration, `dryRun` mode and `nodeRegistration.imagePullSerial` are supported
+- For ClusterConfiguration, there are new fields including `certificateValidityPeriod`,
+`caCertificateValidityPeriod`, `encryptionAlgorithm`, `dns.disabled` and `proxy.disabled`.
+- Support `extraEnvs` for all control plan components
+- `extraArgs` changed from a map to structured extra arguments for duplicates
+- Add a `timeouts` structure for init, join, upgrade and reset.
+
+For details, you can see the [official document](/docs/reference/config-api/kubeadm-config.v1beta4/) below:
+
+- Support custom environment variables in control plane components under `ClusterConfiguration`.
+Use `apiServer.extraEnvs`, `controllerManager.extraEnvs`, `scheduler.extraEnvs`, `etcd.local.extraEnvs`.
+- The ResetConfiguration API type is now supported in v1beta4. Users are able to reset a node by passing
+a `--config` file to `kubeadm reset`.
+- `dryRun` mode is now configurable in InitConfiguration and JoinConfiguration.
+- Replace the existing string/string extra argument maps with structured extra arguments that support duplicates.
+ The change applies to `ClusterConfiguration` - `apiServer.extraArgs`, `controllerManager.extraArgs`,
+ `scheduler.extraArgs`, `etcd.local.extraArgs`. Also to `nodeRegistrationOptions.kubeletExtraArgs`.
+- Added `ClusterConfiguration.encryptionAlgorithm` that can be used to set the asymmetric encryption
+ algorithm used for this cluster's keys and certificates. Can be one of "RSA-2048" (default), "RSA-3072",
+  "RSA-4096" or "ECDSA-P256".
+- Added `ClusterConfiguration.dns.disabled` and `ClusterConfiguration.proxy.disabled` that can be used
+  to disable the CoreDNS and kube-proxy addons during cluster initialization.
+  Skipping the related addons phases, during cluster creation will set the same fields to `true`.
+- Added the `nodeRegistration.imagePullSerial` field in `InitConfiguration` and `JoinConfiguration`,
+  which can be used to control if kubeadm pulls images serially or in parallel.
+- The UpgradeConfiguration kubeadm API is now supported in v1beta4 when passing `--config` to
+  `kubeadm upgrade` subcommands.
+  For upgrade subcommands, the usage of component configuration for kubelet and kube-proxy, as well as
+  InitConfiguration and ClusterConfiguration, is now deprecated and will be ignored when passing `--config`.
+- Added a `timeouts` structure to `InitConfiguration`, `JoinConfiguration`, `ResetConfiguration` and
+  `UpgradeConfiguration` that can be used to configure various timeouts.
+  The `ClusterConfiguration.timeoutForControlPlane` field is replaced by `timeouts.controlPlaneComponentHealthCheck`.
+  The `JoinConfiguration.discovery.timeout` is replaced by `timeouts.discovery`.
+- Added a `certificateValidityPeriod` and `caCertificateValidityPeriod` fields to `ClusterConfiguration`.
+  These fields can be used to control the validity period of certificates generated by kubeadm during
+  sub-commands such as `init`, `join`, `upgrade` and `certs`.
+  Default values continue to be 1 year for non-CA certificates and 10 years for CA certificates.
+  Also note that only non-CA certificates are renewable by `kubeadm certs renew`.
+
+These changes simplify the configuration of tools that use kubeadm
+and improve the extensibility of kubeadm itself.
+
+### How to migrate v1beta3 configuration to v1beta4?
+
+If your configuration is not using the latest version, it is recommended that you migrate using
+the [kubeadm config migrate](/docs/reference/setup-tools/kubeadm/kubeadm-config/#cmd-config-migrate) command.
+
+This command reads an existing configuration file that uses the old format, and writes a new
+file that uses the current format.
+
+#### Example {#example-kubeadm-config-migrate}
+
+Using kubeadm v1.31, run `kubeadm config migrate --old-config old-v1beta3.yaml --new-config new-v1beta4.yaml`
+
+## How do I get involved?
+
+Huge thanks to all the contributors who helped with the design, implementation,
+and review of this feature:
+
+- Lubomir I. Ivanov ([neolit123](https://github.com/neolit123))
+- Dave Chen([chendave](https://github.com/chendave))
+- Paco Xu ([pacoxu](https://github.com/pacoxu))
+- Sata Qiu([sataqiu](https://github.com/sataqiu))
+- Baofa Fan([carlory](https://github.com/carlory))
+- Calvin Chen([calvin0327](https://github.com/calvin0327))
+- Ruquan Zhao([ruquanzhao](https://github.com/ruquanzhao))
+
+For those interested in getting involved in future discussions on kubeadm configuration,
+you can reach out kubeadm or [SIG-cluster-lifecycle](https://github.com/kubernetes/community/blob/master/sig-cluster-lifecycle/README.md) by several means:
+
+- v1beta4 related items are tracked in [kubeadm issue #2890](https://github.com/kubernetes/kubeadm/issues/2890).
+- Slack: [#kubeadm](https://kubernetes.slack.com/messages/kubeadm) or [#sig-cluster-lifecycle](https://kubernetes.slack.com/messages/sig-cluster-lifecycle)
+- [Mailing list](https://groups.google.com/forum/#!forum/kubernetes-sig-cluster-lifecycle)