Bump Kubernetes in tests to v1.31.0 and claim support for v1.31

Author: chrischdi

docs/book/src/reference/versions.md

@@ -85,6 +85,7 @@ These diagrams show the relationships between components in a Cluster API releas
 | Kubernetes v1.28  | ✓ >= v1.5.1          | ✓                 | ✓                 | ✓                 |
 | Kubernetes v1.29  |                      | ✓ >= v1.6.1       | ✓                 | ✓                 |
 | Kubernetes v1.30  |                      |                   | ✓ >= v1.7.1       | ✓                 |
+| Kubernetes v1.31  |                      |                   |                   | ✓ >= v1.8.1       |
 
 
 \* There is an issue with CRDs in Kubernetes v1.23.{0-2}. ClusterClass with patches is affected by that (for more details please see [this issue](https://github.com/kubernetes-sigs/cluster-api/issues/5990)). Therefore we recommend to use Kubernetes v1.23.3+ with ClusterClass.
@@ -105,6 +106,7 @@ The Core Provider also talks to API server of every Workload Cluster. Therefore,
 | Kubernetes v1.28 + kubeadm/v1beta3 | ✓ >= v1.5.1          | ✓                  | ✓                  | ✓                  |
 | Kubernetes v1.29 + kubeadm/v1beta3 |                      | ✓ >= v1.6.1        | ✓                  | ✓                  |
 | Kubernetes v1.30 + kubeadm/v1beta3 |                      |                    | ✓ >= v1.7.1        | ✓                  |
+| Kubernetes v1.31 + kubeadm/v1beta4 |                      |                    |                    | ✓ >= v1.8.1        |
 
 The Kubeadm Bootstrap Provider generates kubeadm configuration using the API version recommended for the target Kubernetes version.
 
@@ -121,6 +123,7 @@ The Kubeadm Bootstrap Provider generates kubeadm configuration using the API ver
 | Kubernetes v1.28 + etcd/v3 | ✓ >= v1.5.1          | ✓                 | ✓                 | ✓                 |
 | Kubernetes v1.29 + etcd/v3 |                      | ✓ >= v1.6.1       | ✓                 | ✓                 |
 | Kubernetes v1.30 + etcd/v3 |                      |                   | ✓ >= v1.7.1       | ✓                 |
+| Kubernetes v1.31 + etcd/v3 |                      |                   |                   | ✓ >= v1.8.1       |
 
 The Kubeadm Control Plane Provider talks to the API server and etcd members of every Workload Cluster whose control plane it owns. It uses the etcd v3 API.
 
@@ -140,6 +143,14 @@ The Kubeadm Control Plane requires the Kubeadm Bootstrap Provider.
 
 #### Kubernetes version specific notes
 
+**1.31**:
+
+* All providers:
+  * It is not possible anymore to continuously apply CRDs that are setting `caBundle` to an invalid value (in our case `Cg==`). Instead of setting a dummy value the `caBundle` field should be dropped ([#10972](https://github.com/kubernetes-sigs/cluster-api/pull/10972)).
+* Kubeadm Bootstrap Provider:
+  * `kubeadm` dropped the `control-plane update-status` phase which was used in ExperimentalRetryJoin ([#10983](https://github.com/kubernetes-sigs/cluster-api/pull/10983)).
+  * `kubeadm` introduced the experimental `ControlPlaneKubeletLocalMode` feature gate which will be automatically enabled by CAPI for upgrades to v1.31 to not cause network disruptions ([#10947](https://github.com/kubernetes-sigs/cluster-api/pull/10947)).
+
 **1.29**:
 * In-tree cloud providers are now switched off by default. Please use DisableCloudProviders and DisableKubeletCloudCredentialProvider feature flags if you still need this functionality. (https://github.com/kubernetes/kubernetes/pull/117503)
 

test/e2e/config/docker.yaml

@@ -353,11 +353,11 @@ variables:
   # allowing the same e2e config file to be re-used in different Prow jobs e.g. each one with a K8s version permutation.
   # The following Kubernetes versions should be the latest versions with already published kindest/node images.
   # This avoids building node images in the default case which improves the test duration significantly.
-  KUBERNETES_VERSION_MANAGEMENT: "v1.31.0-rc.1"
-  KUBERNETES_VERSION: "v1.31.0-rc.1"
+  KUBERNETES_VERSION_MANAGEMENT: "v1.31.0"
+  KUBERNETES_VERSION: "v1.31.0"
   KUBERNETES_VERSION_UPGRADE_FROM: "v1.30.2"
-  KUBERNETES_VERSION_UPGRADE_TO: "v1.31.0-rc.1"
-  KUBERNETES_VERSION_LATEST_CI: "ci/latest-1.31"
+  KUBERNETES_VERSION_UPGRADE_TO: "v1.31.0"
+  KUBERNETES_VERSION_LATEST_CI: "ci/latest-1.32"
   ETCD_VERSION_UPGRADE_TO: "3.5.14-0"
   COREDNS_VERSION_UPGRADE_TO: "v1.11.1"
   DOCKER_SERVICE_DOMAIN: "cluster.local"

test/infrastructure/docker/examples/machine-pool.yaml

@@ -35,7 +35,7 @@ metadata:
   namespace: default
 spec:
   replicas: 1
-  version: v1.31.0-rc.1
+  version: v1.31.0
   machineTemplate:
     infrastructureRef:
       apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
@@ -77,7 +77,7 @@ spec:
   replicas: 2
   template:
     spec:
-      version: v1.31.0-rc.1
+      version: v1.31.0
       clusterName: my-cluster
       bootstrap:
         configRef:

test/infrastructure/docker/examples/simple-cluster-ipv6.yaml

@@ -35,7 +35,7 @@ metadata:
   namespace: default
 spec:
   replicas: 1
-  version: v1.31.0-rc.1
+  version: v1.31.0
   machineTemplate:
     infrastructureRef:
       apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
@@ -87,7 +87,7 @@ spec:
       cluster.x-k8s.io/cluster-name: my-cluster
   template:
     spec:
-      version: v1.31.0-rc.1
+      version: v1.31.0
       clusterName: my-cluster
       bootstrap:
         configRef:

test/infrastructure/docker/examples/simple-cluster-without-kcp.yaml

@@ -32,7 +32,7 @@ metadata:
   name: controlplane-0
   namespace: default
 spec:
-  version: v1.31.0-rc.1
+  version: v1.31.0
   clusterName: my-cluster
   bootstrap:
     configRef:
@@ -76,7 +76,7 @@ spec:
       cluster.x-k8s.io/cluster-name: my-cluster
   template:
     spec:
-      version: v1.31.0-rc.1
+      version: v1.31.0
       clusterName: my-cluster
       bootstrap:
         configRef:

test/infrastructure/docker/examples/simple-cluster.yaml

@@ -35,7 +35,7 @@ metadata:
   namespace: default
 spec:
   replicas: 1
-  version: v1.31.0-rc.1
+  version: v1.31.0
   machineTemplate:
     infrastructureRef:
       apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
@@ -80,7 +80,7 @@ spec:
       cluster.x-k8s.io/cluster-name: my-cluster
   template:
     spec:
-      version: v1.31.0-rc.1
+      version: v1.31.0
       clusterName: my-cluster
       bootstrap:
         configRef: