### 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

    /**
     * Determines which of the specified versions of an artifact to use when there are conflicting declarations.
     *
     * @param node1 the first artifact declaration
     * @param node2 the second artifact declaration
     * @return the artifact declaration to use: <code>node1</code>; <code>node2</code>; or <code>null</code>if
     *         this conflict cannot be resolved
     * @since 3.0
     */

    assertTrue(tokL.isSupertypeOf(StringList.class.getGenericInterfaces()[0]));

    @SuppressWarnings("rawtypes") // Trying to test raw class
    TypeToken<Second> tokS = new TypeToken<Second>() {};
    assertTrue(tokS.isSupertypeOf(Second.class));
    assertTrue(tokS.isSupertypeOf(Third.class.getGenericSuperclass()));
  }

  public void testAssignableArrayToClass() {

        }

        // Second read (should overwrite)
        byte[] secondData = { 10, 20, 30, 40 };
        byte[] buffer2 = new byte[10];
        System.arraycopy(secondData, 0, buffer2, 0, secondData.length);
        response.readDataWireFormat(buffer2, 0, secondData.length);

        // Verify second data overwrote first
        for (int i = 0; i < secondData.length; i++) {

        List<String[]> batches = new ArrayList<>();
        batches.add(new String[] { ".", "..", "a", "b" }); // first batch, dot entries filtered
        batches.add(new String[] { "c" }); // second batch
        batches.add(new String[] {}); // last -> NO_MORE_FILES

        // send() answer that mutates the provided response

Because this code is executed before the application **starts** taking requests, and right after it **finishes** handling requests, it covers the whole application **lifespan** (the word "lifespan" will be important in a second 😉).

  private final OkHttpClient client = new OkHttpClient();

  public void run() throws Exception {
    Request request = new Request.Builder()
        .url("http://httpbin.org/delay/1") // This URL is served with a 1 second delay.
        .build();

    // Copy to customize OkHttp for this request.
    OkHttpClient client1 = client.newBuilder()
        .readTimeout(500, TimeUnit.MILLISECONDS)
        .build();

        createdTime = null;
        versionNo = null;

    }

    /**
     * Gets the total number of records.
     * @return The total record count.
     */
    public int getAllRecordCount() {
        return allRecordCount;
    }

    /**
     * Sets the total number of records.
     * @param allRecordCount The total record count.
     */
    public void setAllRecordCount(final int allRecordCount) {

            byte[] buffer1 = new byte[1024];
            int bytesRead1 = stream1.read(buffer1);
            assertEquals(testContent, new String(buffer1, 0, bytesRead1, "UTF-8"));
        }

        // Second read - should work independently
        try (InputStream stream2 = cache.getInputStream()) {
            byte[] buffer2 = new byte[1024];
            int bytesRead2 = stream2.read(buffer2);

			errorResponse: APIErrorResponse{
				Resource: SlashSeparator + bucketName + SlashSeparator,
				Code:     "InvalidAccessKeyId",
				Message:  "The Access Key Id you provided does not exist in our records.",
			},
			shouldPass: false,
		},
		// PUT empty credentials
		{
			method:             http.MethodPut,
			bucketName:         bucketName,
			accessKey:          "",
			secretKey:          "",