### 2. Run MinIO in federated mode

Bucket lookup from DNS federation requires two dependencies

- etcd (for bucket DNS service records)
- CoreDNS (for DNS management based on populated bucket DNS service records, optional)

## Architecture

![bucket-lookup](https://github.com/minio/minio/blob/master/docs/federation/lookup/bucket-lookup.png?raw=true)

### Environment variables

	z, ok := objAPI.(*erasureServerPools)
	if !ok {
		// Prefix usage is empty
		return map[string]uint64{}, nil
	}

	cache := dataUsageCache{}

	prefixUsageCache.InitOnce(30*time.Second,
		// No need to fail upon Update() error, fallback to old value.
		cachevalue.Opts{ReturnLastGood: true, NoWait: true},
		func(ctx context.Context) (map[string]uint64, error) {
			m := make(map[string]uint64)

 * interpret a token.
 *
 * For example, the first line has a parameter name/value pair and the second line has a single
 * token68:
 *
 * ```
 * WWW-Authenticate: Digest foo=bar
 * WWW-Authenticate: Digest foo=
 * ```
 *
 * Similarly, the first line has one challenge and the second line has two challenges:
 *
 * ```
 * WWW-Authenticate: Digest ,foo=bar
 * WWW-Authenticate: Digest ,foo
 * ```
 */

	GlobalDeploymentID string
)

const (
	// DefaultIdleTimeout for idle inactive connections
	DefaultIdleTimeout = 30 * time.Second

	// DefaultReadHeaderTimeout for very slow inactive connections
	DefaultReadHeaderTimeout = 30 * time.Second

	// DefaultMaxHeaderBytes - default maximum HTTP header size in bytes.
	DefaultMaxHeaderBytes = 1 * humanize.MiByte
)

	"github.com/minio/selfupdate"
	gopsutilcpu "github.com/shirou/gopsutil/v3/cpu"
	"github.com/valyala/bytebufferpool"
)

const (
	envMinisignPubKey = "MINIO_UPDATE_MINISIGN_PUBKEY"
	updateTimeout     = 10 * time.Second
)

// For windows our files have .exe additionally.
var minioReleaseWindowsInfoURL = MinioReleaseURL + "minio.exe.sha256sum"

// minioVersionToReleaseTime - parses a standard official release
// MinIO version string.

			case <-readyChan:
				assert.Equal(t, isReady.Load(), true)
			case err := <-errChan:
				if err == nil {
					t.Fatal("invalid configuration detected")
				}
				t.Fatal(err)
			case <-time.After(5 * time.Second):
				t.Fatal("timed out waiting for isReady to be set to true")
			}

			// Change SA token
			if len(c.saNewFilename) > 0 {
				t.Log("Expecting detect changes to the SA token")

 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public class TestLogHandler extends Handler {
  private final Object lock = new Object();

  /** We will keep a private list of all logged records */
  @GuardedBy("lock")
  private final List<LogRecord> list = new ArrayList<>();

  /** Adds the most recently logged record to our list. */
  @Override
  public void publish(@Nullable LogRecord record) {

    WeakReference<?> shadowLoaderReference = doTestClassUnloading();
    GcFinalization.awaitClear(shadowLoaderReference);
  }

  // Create a second ClassLoader and use it to get a second version of the TestEnum class.
  // Run Enums.getIfPresent on that other TestEnum and then return a WeakReference containing the

    Range<Integer> closedRange = Range.closed(4, 8);

    // first range open end, second range open start
    assertEquals(Range.closed(2, 4), Range.lessThan(2).gap(openRange));
    assertEquals(Range.closed(2, 4), openRange.gap(Range.lessThan(2)));

    // first range closed end, second range open start
    assertEquals(Range.openClosed(2, 4), Range.atMost(2).gap(openRange));

    } catch (e: IOException) {
      failConnection(e)
    }
  }

  /** For testing: sends a ping and waits for a pong. */
  @Throws(InterruptedException::class)
  fun writePingAndAwaitPong() {
    writePing()
    awaitPong()
  }

  /** For testing: sends a ping to be awaited with [awaitPong]. */
  @Throws(InterruptedException::class)
  fun writePing() {
    this.withLock {