Add missing env doc for MINIO_DOMAIN (#5705)

cmd/gateway/azure/gateway-azure.go

@@ -75,6 +75,9 @@ ENVIRONMENT VARIABLES:
   UPDATE:
      MINIO_UPDATE: To turn off in-place upgrades, set this value to "off".
 
+  DOMAIN:
+     MINIO_DOMAIN: To enable virtual-host-style requests. Set this value to Minio host domain name.
+
 EXAMPLES:
   1. Start minio gateway server for Azure Blob Storage backend.
       $ export MINIO_ACCESS_KEY=azureaccountname

cmd/gateway/b2/gateway-b2.go

@@ -66,12 +66,14 @@ ENVIRONMENT VARIABLES:
   UPDATE:
      MINIO_UPDATE: To turn off in-place upgrades, set this value to "off".
 
+  DOMAIN:
+     MINIO_DOMAIN: To enable virtual-host-style requests. Set this value to Minio host domain name.
+
 EXAMPLES:
   1. Start minio gateway server for B2 backend.
       $ export MINIO_ACCESS_KEY=accountID
       $ export MINIO_SECRET_KEY=applicationKey
       $ {{.HelpName}}
-
 `
 	minio.RegisterGatewayCommand(cli.Command{
 		Name:               b2Backend,

cmd/gateway/gcs/gateway-gcs.go

@@ -112,6 +112,9 @@ ENVIRONMENT VARIABLES:
   UPDATE:
      MINIO_UPDATE: To turn off in-place upgrades, set this value to "off".
 
+  DOMAIN:
+     MINIO_DOMAIN: To enable virtual-host-style requests. Set this value to Minio host domain name.
+
   GCS credentials file:
      GOOGLE_APPLICATION_CREDENTIALS: Path to credentials.json
 
@@ -122,7 +125,6 @@ EXAMPLES:
       $ export MINIO_ACCESS_KEY=accesskey
       $ export MINIO_SECRET_KEY=secretkey
       $ {{.HelpName}} mygcsprojectid
-
 `
 
 	minio.RegisterGatewayCommand(cli.Command{

cmd/gateway/manta/gateway-manta.go

@@ -1,5 +1,5 @@
 /*
- * Minio Cloud Storage, (C) 2017 Minio, Inc.
+ * Minio Cloud Storage, (C) 2017, 2018 Minio, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -71,6 +71,9 @@ ENVIRONMENT VARIABLES:
   BROWSER:
      MINIO_BROWSER: To disable web browser access, set this value to "off".
 
+  DOMAIN:
+     MINIO_DOMAIN: To enable virtual-host-style requests. Set this value to Minio host domain name.
+
 EXAMPLES:
   1. Start minio gateway server for Manta Object Storage backend.
       $ export MINIO_ACCESS_KEY=manta_account_name
@@ -87,7 +90,6 @@ EXAMPLES:
       $ export MINIO_SECRET_KEY=manta_key_id
       $ export MANTA_KEY_MATERIAL=~/.ssh/custom_rsa
       $ {{.HelpName}}
-
 `
 
 	minio.RegisterGatewayCommand(cli.Command{

cmd/gateway/nas/gateway-nas.go

@@ -53,6 +53,9 @@ ENVIRONMENT VARIABLES:
   UPDATE:
      MINIO_UPDATE: To turn off in-place upgrades, set this value to "off".
 
+  DOMAIN:
+     MINIO_DOMAIN: To enable virtual-host-style requests. Set this value to Minio host domain name.
+
 EXAMPLES:
   1. Start minio gateway server for NAS backend.
       $ export MINIO_ACCESS_KEY=accesskey

cmd/gateway/oss/gateway-oss.go

@@ -65,6 +65,12 @@ ENVIRONMENT VARIABLES:
   BROWSER:
      MINIO_BROWSER: To disable web browser access, set this value to "off".
 
+  UPDATE:
+     MINIO_UPDATE: To turn off in-place upgrades, set this value to "off".
+
+  DOMAIN:
+     MINIO_DOMAIN: To enable virtual-host-style requests. Set this value to Minio host domain name.
+
 EXAMPLES:
   1. Start minio gateway server for Aliyun OSS backend.
       $ export MINIO_ACCESS_KEY=accesskey
@@ -75,7 +81,6 @@ EXAMPLES:
       $ export MINIO_ACCESS_KEY=Q3AM3UQ867SPQQA43P2F
       $ export MINIO_SECRET_KEY=zuf+tfteSlswRu7BJ86wekitnifILbZam1KYY3TG
       $ {{.HelpName}} https://oss.example.com
-
 `
 
 	minio.RegisterGatewayCommand(cli.Command{

cmd/gateway/s3/gateway-s3.go

@@ -59,6 +59,9 @@ ENVIRONMENT VARIABLES:
   UPDATE:
      MINIO_UPDATE: To turn off in-place upgrades, set this value to "off".
 
+  DOMAIN:
+     MINIO_DOMAIN: To enable virtual-host-style requests. Set this value to Minio host domain name.
+
 EXAMPLES:
   1. Start minio gateway server for AWS S3 backend.
       $ export MINIO_ACCESS_KEY=accesskey

cmd/gateway/sia/gateway-sia.go

@@ -1,5 +1,5 @@
 /*
- * Minio Cloud Storage, (C) 2017 Minio, Inc.
+ * Minio Cloud Storage, (C) 2017, 2018 Minio, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -76,13 +76,15 @@ ENVIRONMENT VARIABLES: (Default values in parenthesis)
   UPDATE:
      MINIO_UPDATE: To turn off in-place upgrades, set this value to "off".
 
+  DOMAIN:
+     MINIO_DOMAIN: To enable virtual-host-style requests. Set this value to Minio host domain name.
+
   SIA_TEMP_DIR:        The name of the local Sia temporary storage directory. (.sia_temp)
   SIA_API_PASSWORD:    API password for Sia daemon. (default is empty)
 
 EXAMPLES:
   1. Start minio gateway server for Sia backend.
       $ {{.HelpName}}
-
 `
 
 	minio.RegisterGatewayCommand(cli.Command{

cmd/server-main.go

@@ -55,7 +55,6 @@ DIR:
   filesystem separated by space. You may also use a '...' convention
   to abbreviate the directory arguments. Remote directories in a
   distributed setup are encoded as HTTP(s) URIs.
-
 {{if .VisibleFlags}}
 FLAGS:
   {{range .VisibleFlags}}{{.}}
@@ -69,11 +68,14 @@ ENVIRONMENT VARIABLES:
      MINIO_BROWSER: To disable web browser access, set this value to "off".
 
   REGION:
-     MINIO_REGION: To set custom region. By default it is "us-east-1".
+     MINIO_REGION: To set custom region. By default all regions are accepted.
 
   UPDATE:
      MINIO_UPDATE: To turn off in-place upgrades, set this value to "off".
 
+  DOMAIN:
+     MINIO_DOMAIN: To enable virtual-host-style requests. Set this value to Minio host domain name.
+
 EXAMPLES:
   1. Start minio server on "/home/shared" directory.
       $ {{.HelpName}} /home/shared
@@ -81,6 +83,10 @@ EXAMPLES:
   2. Start minio server bound to a specific ADDRESS:PORT.
       $ {{.HelpName}} --address 192.168.1.101:9000 /home/shared
 
+  3. Start minio server and enable virtual-host-style requests.
+      $ export MINIO_DOMAIN=mydomain.com
+      $ {{.HelpName}} --address mydomain.com:9000 /mnt/export
+
   3. Start minio server on a 12 disks server.
       $ {{.HelpName}} /mnt/export1/ /mnt/export2/ /mnt/export3/ /mnt/export4/ \
           /mnt/export5/ /mnt/export6/ /mnt/export7/ /mnt/export8/ /mnt/export9/ \