- Improved scheduler robustness to ensure that unschedulable pods are reconsidered for scheduling when appropriate. ([#73700](https://github.com/kubernetes/kubernetes/pull/73700), [#72558](https://github.com/kubernetes/kubernetes/pull/72558), [@denkensk](https://github.com/denkensk), [#73078](https://github.com/kubernetes/kubernetes/pull/73078), [@Huang-Wei...

- Kubeadm: avoid panicing if the user has malformed the kubeconfig in the cluster-info config map to not include a valid current context. Include proper validation at the appropriate locations and throw errors instead. ([#134725](https://github.com/kubernetes/kubernetes/pull/134725), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

Pod priority and preemption is now enabled by default. Even if you don't plan to use this feature, you might need to take some action immediately after upgrading. In multi-tenant clusters where not all users are trusted, you are advised to create appropriate quotas for two default priority classes, system-cluster-critical and system-node-critical, which are added to clusters by default. `ResourceQuota` should be created to limit users from creating Pods at these priorities if not all users of your cluster...

- Kubeadm: avoid panicing if the user has malformed the kubeconfig in the cluster-info config map to not include a valid current context. Include proper validation at the appropriate locations and throw errors instead. ([#134724](https://github.com/kubernetes/kubernetes/pull/134724), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

- Kubeadm: avoid panicing if the user has malformed the kubeconfig in the cluster-info config map to not include a valid current context. Include proper validation at the appropriate locations and throw errors instead. ([#134723](https://github.com/kubernetes/kubernetes/pull/134723), [@neolit123](https://github.com/neolit123)) [SIG Cluster Lifecycle]

        // We have metadata retrieval problems, or there are cycles that have been detected
        // so we give this back to the calling code and let them deal with this information
        // appropriately.

        if (result.hasMetadataResolutionExceptions()
                || result.hasVersionRangeViolations()
                || result.hasCircularDependencyExceptions()) {
            return result;
        }

<table>
  <tr>
    <td>previous</td>
    <td>now</td>
  </tr>
  <tr>
    <td>GET /swagger.json</td>
    <td>GET /openapi/v2

## **4. Run Sample Applications**

After installing Hive, Hadoop and Spark successfully, we can now proceed to run some sample applications to see if they are configured appropriately.  We can use Spark Pi and Spark WordCount programs to validate our Spark installation. We can also explore how to run Spark jobs from the command line and Spark shell.

### **4.1 Spark Pi**

- StatefulSet Controller now waits for PersistentVolumeClaim deletion before creating pods. ([#93457](https://github.com/kubernetes/kubernetes/pull/93457), [@ymmt2005](https://github.com/ymmt2005))
- StreamWatcher now calls HandleCrash at appropriate sequence. ([#93108](https://github.com/kubernetes/kubernetes/pull/93108), [@lixiaobing1](https://github.com/lixiaobing1))

 * corresponding entries will be dropped from the cache. If an error occurs while writing a cache
 * value, the edit will fail silently. Callers should handle other problems by catching
 * `IOException` and responding appropriately.
 *
 * @constructor Create a cache which will reside in [directory]. This cache is lazily initialized on
 *     first access and will be created if it does not exist.
 * @param directory a writable directory.