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**

 * Running on http://127.0.0.1:5000
Press CTRL+C to quit
```

## Start MinIO with Lambda target

Register MinIO with a Lambda function, we are calling our target name as `function`, but you may call it any other friendly name of your choice.
```
MINIO_LAMBDA_WEBHOOK_ENABLE_function=on MINIO_LAMBDA_WEBHOOK_ENDPOINT_function=http://localhost:5000 minio server /data &
...
...

// preferReaders can mark readers as preferred.
// These will be chosen before others.
func (p *parallelReader) preferReaders(prefer []bool) {
	if len(prefer) != len(p.orgReaders) {
		return
	}
	// Copy so we don't change our input.
	tmp := make([]io.ReaderAt, len(p.orgReaders))
	copy(tmp, p.orgReaders)
	p.readers = tmp
	// next is the next non-preferred index.
	next := 0
	for i, ok := range prefer {
		if !ok || p.readers[i] == nil {

export MINIO_IDENTITY_LDAP_GROUP_SEARCH_FILTER='(&(objectclass=groupOfNames)(member=%d))'
minio server ~/test
```

You can make sure it works appropriately using our [example program](https://raw.githubusercontent.com/minio/minio/master/docs/sts/ldap.go):

```
$ go run ldap.go -u foouser -p foopassword

##### Credentials
{
        "accessKey": "NUIBORZYTV2HG2BMRSXR",

- **We do not recommend upgrading one MinIO server at a time, the product is designed to support parallel upgrades please follow our recommended guidelines.**

## Explore Further

- [MinIO Erasure Code Overview](https://min.io/docs/minio/linux/operations/concepts/erasure-coding.html)

**In our tests we also found ext4 does not honor POSIX O_DIRECT/Fdatasync semantics, ext4 trades performance for consistency guarantees. Please avoid ext4 in your setup.**

	// 	if err != nil {
	// 		return "", fmt.Errorf("Error reading body: %v", err)
	// 	}
	// 	fmt.Printf("bodyBuf (for LDAP login page): %s\n", string(bodyBuf))
	// }

	// Fill the login form with our test creds:
	// fmt.Printf("login form url: %s\n", lastReq.URL.String())
	formData := url.Values{}
	formData.Set("login", username)
	formData.Set("password", password)

			errorResponse: APIErrorResponse{
				Resource: SlashSeparator + bucketName + SlashSeparator,
				Code:     "InvalidAccessKeyId",
				Message:  "The Access Key Id you provided does not exist in our records.",
			},
			shouldPass: false,
		},
	}

	for i, testCase := range testCases {
		if i != 1 {
			continue
		}

	for bucket, records := range dnsBuckets {
		if bucketsSet.Contains(bucket) {
			continue
		}

		if globalDomainIPs.Intersection(set.CreateStringSet(getHostsSlice(records)...)).IsEmpty() {
			// This is not for our server, so we can continue
			continue
		}

		wg.Add(1)
		go func(bucket string) {
			defer wg.Done()
			// We go to here, so we know the bucket no longer exists,

		strict = true
	}
	// Shallow copy input
	versions = append(make([][]xlMetaV2ShallowVersion, 0, len(versions)), versions...)

	var nVersions int // captures all non-free versions

	// Our result
	merged = make([]xlMetaV2ShallowVersion, 0, len(versions[0]))
	tops := make([]xlMetaV2ShallowVersion, len(versions))
	for {
		// Step 1 create slice with all top versions.
		tops = tops[:0]