### **4.1 Spark Pi**

Test the Spark installation by running the following compute intensive example, which calculates pi by “throwing darts” at a circle. The program generates points in the unit square ((0,0) to (1,1)) and counts how many points fall within the unit circle within the square. The result approximates pi.

Follow these steps to run the Spark Pi example:

- Login as user **‘spark’**.

func TestNegativeEOFReader(t *testing.T) {
	r := negativeEOFReader(10)
	scanner := NewScanner(&r)
	c := 0
	for scanner.Scan() {
		c++
		if c > 1 {
			t.Error("read too many lines")
			break
		}
	}
	if got, want := scanner.Err(), ErrBadReadCount; got != want {
		t.Errorf("scanner.Err: got %v, want %v", got, want)
	}
}

https://kubernetes.io/docs/concepts/containers/runtime-class/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## rootUser and rootPassword is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html ## rootUser: "" rootPassword: "" ## Use existing Secret that store following variables: ## ## | Chart var | .data.<key> in Secret | ## |:-------- ## | rootUser | rootUser | ## | rootPassword | rootPassword...

   * or even that an interrupt occurred (if the spurious wakeup happens before the interrupt).
   *
   * Fundamentally, there's not really anything we can do about that. In the unlikely event that it
   * comes up in practice (maybe through some kind of sanitizer-like testing that intentionally
   * inflicts spurious interrupts on us?), we might have to accept some flakiness or disable some

* Fix a scalability issue where high rates of event writes degraded etcd performance. ([#64539](https://github.com/kubernetes/kubernetes/pull/64539), [@ccding](https://github.com/ccding))
* Properly manage security groups for loadbalancer services on OpenStack. ([#65373](https://github.com/kubernetes/kubernetes/pull/65373), [@multi-io](https://github.com/multi-io))

        crawlingInfoHelper.documentExpires = currentTime + 5000;

        // For this test, we'll focus on the documentExpires fallback logic
        // since creating full CrawlingConfig mocks would require implementing many abstract methods
        Date result = crawlingInfoHelper.documentExpires != null ? new Date(crawlingInfoHelper.documentExpires) : null;
        assertNotNull(result);
        assertEquals(currentTime + 5000, result.getTime());

   * previously configured separator between each.
   */
  public String join(Iterable<?> parts) {
    /*
     * If we can quickly determine how many elements there are likely to be, then we can use the
     * fastest possible implementation, which delegates to the array overload of String.join.
     *

https://kubernetes.io/docs/concepts/containers/runtime-class/ ## runtimeClassName: "" ## Set default rootUser, rootPassword ## rootUser and rootPassword is generated when not set ## Distributed MinIO ref: https://min.io/docs/minio/linux/operations/install-deploy-manage/deploy-minio-multi-node-multi-drive.html ## rootUser: "" rootPassword: "" ## Use existing Secret that store following variables: ## ## | Chart var | .data.<key> in Secret | ## |:-------- ## | rootUser | rootUser | ## | rootPassword | rootPassword...

     * character matches any number of characters in part of a name. If
     * the expression begins with one or more '?'s then exactly that
     * many characters will be matched whereas if it ends with '?'s
     * it will match that many characters <i>or less</i>.
     * <p>
     * Wildcard expressions will not filter workgroup names or server names.
     *
     * <blockquote><pre>
     * winnt> ls c?o*

   * the underlying collection.
   *
   * <p>The returned collection isn't threadsafe or serializable, even if {@code unfiltered} is.
   *
   * <p>Many of the filtered collection's methods, such as {@code size()}, iterate across every
   * element in the underlying collection and determine which elements satisfy the filter. When a