3 Tier Deployment Setup (ELB-Rails-MySQL)

Objective

To create a 3-tiered production-like deployment in Amazon EC2 using Amazon's Elastic Load Balancing service and ServerTemplates published by RightScale for launching an Apache-Rails-Passenger application.

Table of Contents

1. Overview
2. Deployment Setup
3. Database Setup
4. Load Balancer Setup
5. Application Setup
6. Test the Deployment
7. Next Steps

Prerequisites

• Access to add/create/edit DNS records with a supported DNS provider (e.g. DNSMadeEasy, DynDNS, Route53). 
• 'designer' 'actor' and 'security_manager' user role privileges are required, although the 'security_manager' user role privilege may not be required if security group with the appropriate firewall permissions already exist.

Overview

Although this end-to-end tutorial was originally designed as a hands-on exercise in an Instructor Led Training course, anyone can follow the tutorial and use it as a learning tool as well. The class environment influences naming conventions, hence we often precede names with initials or names in our examples. (For example, an A Record for John Doe named "jd-www", rather than simply "www"). Be sure to provide enough time for yourself to complete the end-to-end exercise. (Estimate: 1-3hrs) 

This tutorial will demonstrate how to build a common 3-tier website architecture in the cloud using some of RightScale's ServerTemplates. 

• Amazon Elastic Load Balancing
• Apache-Rails-Passenger Application servers
• MySQL Database servers

Disclaimers

• This tutorial assumes that you are launching all servers into the same cloud/region. 
• As a best practice, it's recommended to deploy each tier across more than one Datacenters / Zones (if supported by the cloud) for high-availability purposes.

Deployment Setup

Create a Deployment

It's recommended that you create a new deployment (Manage > Deployments) for each new project or reference architecture that you're going to build because you do not want to accidentally inherit any unknown configuration settings.

See Create a New Deployment. (Requires 'actor' user role privileges.)

Tip: It's recommended that you create a bookmark to the deployment's Servers tab for quick navigation back to the deployment at any time.

Create Cloud-specific Resources

Prerequisites: Requires 'actor' user role privileges in the RightScale account to create SSH Keys and Elastic IPs, and 'security_manager' privileges to create security groups.

Each cloud infrastructure is unique and requires different resources in order to launch a server in their cloud. Depending on the type of cloud infrastructure that you're going to use to launch servers, you will find it useful to create some of the required cloud-specific resources beforehand so that you can select them in the "Add Server Wizard" when you add servers into a deployment. Cloud resources are also cloud-specific. For example, you cannot launch an EC2 instance in the 'us-east' region with an 'us-west' security group. 

SSH Key

If the cloud does not require the use of an SSH Key, you can ignore this step. 

SSH Keys are used for authentication purposes to create SSH console sessions for root level access to the instance. Although you are required to associate an SSH Key to a server before you can launch it, the private key material is no longer required if managed SSH (Server Login Control) is enabled for the account (Settings > Account Settings > SSH). By default, Server Login Control is enabled at the account level, where a user's own unique RSA key pair (Settings > User Settings > SSH) is used for authentication purposes for establishing SSH console sessions on all RightLink-enabled instances.

You can either use an existing SSH Key or create a new one.

• Amazon EC2
  • Create a New SSH Key

Security Groups

If the cloud does not support Security Groups, you can ignore this step. 

Security groups are firewall settings that apply to instances within a cloud at the infrastructure layer. Security groups are typically used to control ingress communication (i.e. inbound communication to an instance over a particular port and protocol) however, some clouds support the use of security groups to also control egress communication (i.e. outbound requests from the instance). Once you create a security group you can create different firewall rules that control the level of access to instances launched with that particular security group(s). Firewall rules are enforced at the cloud (infrastructure) level using IP-based or Group-based permissions.

If you are building this deployment for demonstration and testing purposes, you can simply create a single security group for all servers in your deployment. 

The steps for creating a single security group are different depending on the type of account and cloud that you are using.

• Amazon Web Services - EC2
• OpenStack (Juno)
• Google Compute Engine 
• CloudStack

Once you are successful setting up your first multi-tier deployment you can set up more secure firewall permissions that would be more realistic for production environments. See Configuring multiple Security Groups for a multi-tiered Deployment.

Remappable Public IP Addresses

Some clouds support the use of public IP addresses that you can associate with a server at launch time or remap to another running server, as necessary for lifecycle management scenarios. It's recommended that you use this service, if available for front-end load balancer or web servers that are designed to be public facing. If you're using dedicated HAProxy load balancer servers, you should create/reserve one IP address for each load balancer server. Typically, you will have two HAProxy load balancer servers for high-availability and failover purposes. If you are using a cloud's load balancing service such as Amazon Elastic Load Balancers (ELB) or Rackspace Cloud Load Balancers (CLB) you cannot assign remappable IP addresses. In such cases, skip this step.

• Amazon EC2
  • Create a New Elastic IP (EIP)
• Rackspace Private, CloudStack, OpenStack, HP, Datapipe
  • ​Create a New (Public) IP Address

Create DNS Records

In a typical 3-tier architecture setup, DNS A records are used to create fully qualified domain names (FQDNs) that map to a particular server or tier of servers. The diagram below shows a typical example of a 3-tier website architecture.

In this type of architecure, the application servers and any "slave" database servers locate the "master" database server by using Master-DB's FQDN (e.g. db-master.example.com), which points to the Master-DB's private IP address. Similarly, front-end web traffic can be routed to a FQDN (e.g. www.example.com) where each load balancer server has a DNS record for that FQDN so that incoming requests are routed to one of the load balancer servers. Since the IP address of an instance in the cloud is often dynamically assigned at launch time, you are required to use a DNS provider that supports dynamic DNS (i.e. the ability to dynamically update the IP address of an A record) for the Master-DB server (at a minimum). You can also use the same DNS provider for creating FQDNs for the load balancer servers. However, since they do not require the use of dynamic DNS, any DNS provider can be used.

TTLs

When you create the DNS records, it's important to set appropriate TTLs to ensure that servers will not stay connected to an old IP address that is no longer assigned to a functional server. For example, the DNS record that points to the "master" database server should have a low TTL to ensure that the application servers will connect to the correct server within a reasonable amount of time. It's strongly recommended that you use a TTL of 60 seconds for the DNS record that points to the "master" database server. If you are also creating DNS records for the front-end load balancer servers, you can use a more conservative TTL than the database tier. (e.g. 1800 seconds)

Note: If you are using Rackspace's Cloud DNS service, you must use a TTL of 300 seconds because that is the lowest allowable TTL. Be sure to change the 'Database DNS TTL Limit' input from 60 (default) to 300.

You will need to create DNS records for the following servers:

• Each Load Balancer Server or Load Balancing service (e.g. Amazon Elastic Load Balancer, Rackspace Cloud Load Balancer, etc.)
• Master Database Server
• Slave Database Server (optional)

Note: Be aware that you will need to create Database Servers in RightScale before you create DNS A records from them, as private IP addresses are not known until a server has been created successfully. If you are using existing servers you have already created in RightScale for this new deployment, you can proceed with DNS A record creation.

RightScale's ServerTemplates contain scripts that support one of the following DNS providers. Create an account with one of the DNS providers below and set up the A records accordingly.

• Domain Setup with DNSMadeEasy
• Domain Setup with DynDNS
• Domain Setup with Amazon's Route 53 (Aws DNS)
• Domain Setup with Rackspace Cloud DNS

Create Credentials

Prerequisites: Requires 'designer' user role privileges in the RightScale account to create a new credential.

Important!
Only the user who created the credential and any 'admin' users will be able to view and modify an existing credential. 

Credentials are a way of passing sensitive information to a script (as an input) in a discrete manner without making the actual value visible in the Dashboard. As a best practice, many of the ServerTemplates published by RightScale are preconfigured to use certain credentials. It's recommended that you create these common credentials in your own account. If they already exist and apply to a different deployment, you might want to create a new set of credentials to avoid any conflicts. In such cases, it's helpful to use a common prefix to group the credentials together. (e.g. APP1_DBADMIN_USER)

If you try to launch a server where one of the inputs references a credential that does not exist in the RightScale account, you will receive an error message and will not be able to launch the server. Therefore, it's best to create any required credentials before you configure and launch a server. Depending on your cloud provider and backup storage selections, you may want to create additional credentials.

At a minimum, create the following credentials. See Create a New Credential for more information.

Common Credentials for a 3-Tier Linux Architecture

If you are going through a 3-tier tutorial you should create the following credentials with your own values or you can use the example values, if desired.

• DBADMIN_USER - Username of a database user with administrator privileges. Use this credential for the "Database Admin Username" input.
  • 3 Tier Tutorial: admindb
• DBADMIN_PASSWORD - Password for DBADMIN_USER. Use this credential for the "Database Admin Password" input.
  • 3 Tier Tutorial: a1234
     
• DBAPPLICATION_USER - User name of a database user with user-level privileges. Use this credential for the "Database Application Username" input. Note: For PostgreSQL databases, the username cannot start with a number.
  • 3 Tier Tutorial: johnsmith
• DBAPPLICATION_PASSWORD - Password for DBAPPLICATION_USER. Use this credential for the "Database Application Password" input.
  • 3 Tier Tutorial: 1234z
     
• DBREPLICATION_USER - Username of a database user with replication permissions on the server. Use this credential for the "Database Replication Username" input.
  • 3 Tier Tutorial: dbrpl
• DBREPLICATION_PASSWORD - Password for DBREPLICATION_USER. Use this credential for the "Database Replication Password" input.
  • 3 Tier Tutorial: ic6789
     
• DNS_USER* - Username that's used to log into your DNS provider and update DNS records. It's commonly used to update the A record with the private IP address of the "master" database server. Use this credential for the "DNS User" input.
• DNS_PASSWORD* - Password for DNS_USER. Use this credential for the "DNS Password" input.

* If you use Amazon Route 53 or Rackspace Cloud DNS as your DNS provider, you do not need to set up separate DNS user name and password credentials because your cloud credentials are used for authentication purposes. 

Remote Object Storage (ROS)

ServerTemplates published by RightScale have built-in support for several remote object storage (ROS) solutions. Valid cloud credentials are required to retrieve "private" files from an ROS container, create a new container, or store files in a container (such as a binary database backup files).

Set up your desired ROS service(s) and create the recommended user-defined credentials, which you will use when you define inputs for your deployments.

• Set up Amazon S3
• Set up Google Cloud Storage
• Set up Rackspace Cloud Files
• Set up Windows Azure Cloud Storage
• Set up SoftLayer Object Storage
• Set up OpenStack Object Storage (Swift)
• Set up HP Cloud Object Storage

Software Repositories

Source Control Management (SVN, GitHub, FTP, rsync)

If you are using a source control management (SCM) system to host your application code, you will need to create the appropriate credentials to retrieve your source code from the specified repository.

• GIT_SSH_KEY - A valid SSH Key for accessing a private repository hosted on GitHub.com. Use this credential for the "Account credential" input. 
   
• SVN_USERNAME - The SVN username that has access to the specified repository. Use this credential for the "Account name" input.
• SVN_PASSWORD - Password for SVN_USERNAME. Use this credential for the "Account credential" input.

• FTP_USERNAME - The username that you use to log into the FTP server to access your software repository. Use this credential for the "Account name" input.
• FTP_PASSWORD - Password for FTP_USERNAME. Use this credential for the "Account credential" input.

You can also download application source code from rsync sources.

• RSYNC_USERNAME - The username to log into the remote host. Use this credential for the "Account name" input.
• RSYNC_SSH_KEY - If the remote host supports SSH key authentication, create an SSH Key for rsyncing data between servers. Use this credential for the "Account credential" input.

Secure Sockets Layer (SSL)

Load Balancer

If you are using SSL to support HTTPS access, you should create credentials for any of the following values that apply. See How do I create an SSL certificate for my web server?

• LB_STATUS_USERNAME - Optional user name to require in order to log in to the HAProxy status report page.
• LB_STATUS_PASSWORD - Optional password corresponding to LB_STATUS_USERNAME.
• SSL_CERTIFICATE - Contents of the X.509/PEM-format SSL server certificate used for enabling HTTPS communications.
• SSL_CERTIFICATE_CHAIN - The certificate authority (CA) certificate chain associated with the server certificate used to set up HTTPS communications.
• SSL_CERTIFICATE_KEY - The SSL server certificate's private key, in PEM format.
• SSL_PASSPHRASE - If required by an SSL certificate, you must provide the passphrase so Apache can start.

Database

If you are using the public network to connect to the master database server, it's recommended that you use SSL to encrypt the data being transfered between the master database server and the associated slave and/or application servers. Note: SSL is currently only supported in the Database Manager for MySQL 5.1/5.5 ServerTemplates.

• MYSQL_SSL_CERT - The name of your CA SSL Certificate.
• MYSQL_SSL_MASTER_CERT - The name of your Master SSL Certificate.
• MYSQL_SSL_MASTER_KEY - The name of your Master SSL Key.
• MYSQL_SSL_SLAVE_CERT - The name of your Slave SSL Certificate.
• MYSQL_SSL_SLAVE_KEY - The name of your Slave SSL Key.

Database Tier Setup

Upload the Database Dump File

The ServerTemplate contains scripts that can retrieve a database dump file from a container in one of the supported Remote Object Storage (ROS) providers (e.g. Amazon S3, Rackspace Cloud Files). See Database Dump Retrieval.

Create a new bucket/container and upload your database dump file. The file can remain a 'private' object because your cloud credentials can be used (as inputs) for authentication purposes to retrieve the file. Supported file types include .gz, .bz2, and .zip.  Make sure the uploaded file maintains the its file extension.

Warning! The filename of the MySQL dump file cannot contain a dash (-) in its prefix name. For example, if your dump file is named, 'my-app-201205030022.gz', you must manually rename it to be 'my_app-201205030022.gz' where you use an underscore (_) to replace the dash, otherwise the script (do::do_dump_import) that imports the database dump file into the instance will fail.

• Upload Files to an Amazon S3 Bucket
• Upload Files to a Rackspace Cloud Files Container
• Upload Files to an OpenStack (Swift) Container
• Upload Files to a Google Cloud Storage Bucket
• Upload Files to a Windows Azure Blob Container
• Upload Files to a SoftLayer Object Storage Container
• Upload Files to an HP Object Storage Container

If you are setting up a database server for testing purposes or if you do not have your own dump file, you can use the following sample MySQL dump file to complete the tutorial. The sample is a gzip (.gz) file.

• app_test-201109010029.gz

Add a Server

Follow these steps to add a database server to the deployment.

1. Go to the MultiCloud Marketplace (Design > MultiCloud Marketplace > ServerTemplates) and import the most recently published revision of the following ServerTemplate into the RightScale account.
   • Database Manager for MySQL 5.1 (v13.5.x LTS) or 
   • Database Manager for MySQL 5.5 (v13.5.x LTS)
2. From the imported ServerTemplate's show page, click the Add Server button.
3. Select the cloud for which you will configure a server. 
4. Select the deployment for the new server.
5. Next, the Add Server Assistant wizard will walk you through the remaining steps that are required to create a server based on the selected cloud.
   • Server Name - Provide a nickname for your new database server (e.g., mysql-db1). Do not include "master" or "slave" in the name, because a database server's role can change in the future.
   • Select the appropriate cloud-specific resources (e.g. SSH Key, Security Group, etc.) that are required in order to launch a server into the chosen cloud. The required cloud resources may differ depending on the type of cloud infrastructure. If the cloud supports multiple datacenters/zones, select a specific zone. Later, when you create the other database server you will use a different datacenter/zone to ensure high-availability. For more information, see Add Server Assistant.
   • Important! If you are not using volumes to store the database, you must select an instance type that has disk space that's at least twice as large as your database because LVM snapshots are performed locally on the instance before they are gzipped and saved to the specified ROS location. Also, although these ServerTemplates will work with any instance size, you may experience degraded performance with small instance sizes (such as EC2 micro, Rackspace 256MB etc) due to lack of system resources. We do not recommend smaller instance types for production use.
6. Click Confirm, review the server's configuration and click Finish to create the server.

Configure Inputs

The next step is to define the properties of your database server or servers by entering values for inputs. It is simplest and best to do this at the deployment level. For a detailed explanation of how inputs are defined and used in Chef recipes and RightScripts, see Understanding Inputs.

The inputs that you need to provide values for will depend on which options you're going to use. The ServerTemplate is very flexible and supports a variety of different configurations. You must provide values for the required inputs based on the chosen options.

• Where will the contents of the database be stored?
  • On volumes attached to the instance.
  • On the local/ephemeral drive.
• If you're using volumes, are you going to use a stripe?
  • Yes - Use a stripe of multiple volumes.
  • No - Use a single volume. 
  • INPUTS: Block Device Mount Directory (1), Nickname (1), Number of Volumes in the Stripe (1), Total Volume Size (1)
• Are you building a master-slave database setup?
  • Yes
  • No
  • INPUTS: Database Master FQDN, Database Master DNS Record ID, Database Slave DNS Record ID, Database Replication Password, Database Replication Username
• Will there be replication between master-slave database servers across different clouds/regions? If yes, you should set up SSL.
  • Yes
  • No
  • INPUTS: CA SSL Certificate, Master SSL Certificate, Master SSL Key, Slave SSL Certificate, Slave SSL Key
• What are you going to use to take "primary" backups of the database?
  • Volume Snapshots
  • Binary Dumps to an ROS container (e.g. S3 bucket, Cloud Files container, etc.)
  • INPUTS: Primary Backup Secret (default), Primary Backup User (default), Primary Backup Storage Cloud (default), Primary Backup Storage Cloud Endpoint URL (default), Database Backup Lineage
• Are you going to take "secondary" backups of the database? If yes, which ROS provider will you use?
  • Amazon S3, Rackspace Cloud Files (US or UK), Google Cloud Storage, Azure Blob Storage, Swift-based Storage, SoftLayer Object Storage
  • INPUTS: Secondary Backup Storage Cloud (default), Secondary Backup Secret (default), Secondary Backup User (default), Secondary Backup Storage Container (1), Secondary Backup Storage Cloud Endpoint URL (default), Secondary Backup Storage Container (2)
• Which DNS provider are you using for dynamic DNS at the database level?
  • DNS Made Easy
  • DynDNS
  • Amazon Route 53
  • Rackspace Cloud DNS
  • INPUTS: DNS Service Provider, DNS Password, DNS User, Database Master FQDN, Database Master DNS Record ID, Database Slave DNS Record ID, Cloud DNS region

Set Inputs at the Deployment Level

Go to the deployment's Inputs tab (Manage > Deployments > your deployment > Inputs) and click Edit.

Although you can enter values for missing inputs as text values, it's strongly recommended that you set up credentials for passing sensitive information to scripts such as passwords or any other sensitive data.

Rackspace only
If you use Rackspace for your database servers and backup storage (i.e., Cloud Files) the storage-related Chef recipes will use Rackspace Service Net (SNET) by default. SNET is Rackspace's internal private networking service for optimized communication between Rackspace Cloud Servers and Cloud Files. If SNET is not supported in your Rackspace environment, you must set the "Rackspace SNET Enabled for Backup" input to false; otherwise, all backup and restore operations that rely on Cloud Files will fail.

Block Device

If the cloud supports the use of mountable volumes (e.g. AWS EBS Volumes, CloudStack volumes, etc.), primary backups will be saved as volume snapshots. It's strongly recommended that you use volumes to store the contents of the MySQL database for efficiency and performance reasons.

However, if the cloud does not support mountable volumes (e.g. Rackspace First Generation), primary backups must be saved to a Remote Object Storage location. In such cases, the contents of the MySQL database will be stored locally on the instance's ephemeral drive and backups of the database will be stored as binary dump files to the specified object storage container.

Required

Base

Advanced

DB

DB_MYSQL

Most of the MySQL-specific inputs are preconfigured with acceptable default values, but you can change any values, as necessary.

However, if you are setting up master-slave database replication between database servers located in different clouds/regions, you are forced to use the public network for replication. Therefore, you have to perform database replication over the public network (Database Replication Network Interface = public).

SYS_DNS

Launch the Database Server

After configuring your inputs, launch your newly configured master database server.

1. Go to the deployment's Servers tab and launch the database server. When you view the input confirmation page, there should not be any missing values (highlighted in red) for inputs that are required by any of the server's boot scripts. If there are any inputs highlighted in red, cancel the launch and add the missing values at the deployment level before launching the server again. Refer to the instructions in Launch a Server if you are not familiar with this process. Click the Launch (not 'Save and Launch') button at the bottom of the input confirmation page. 

Initialize the Master Database Server

Wait for the server to reach the "operational" state before you run a script to initialize the database server.

1. Go to the "current" server's Scripts tab and run the db::do_init_and_become_master operational script to initialize it as the "Master" database server.
2. (Optional) You can go to the "current" server's Audit Entries tab to track the status of the operation.

The script performs the following actions:

• Registers it as the "master" database server and assign appropriate replication privileges and machine tags. (e.g. rs_dbrepl:master_instance_uuid=01-AVMV4MFHJQOK0 and rs_dbrepl:master_active=20130313200931-bob)
• For cloud providers with volume support, it creates and mounts either a single volume or group of striped volumes for data storage.
• Creates a database backup to primary storage.

• Schedules a cron job to run backups to primary storage once every hour from a "slave" and once per day from the "master" server. A random time is chosen for taking the backups, however inputs are available for setting a specific time for backups. For example, you may want to make sure that the daily backup from the "master" server is taken at off-peak teams. (For information on modifying the default backup schedule, see the Database Manager for MySQL 5.1/5.5 Runbook.)
• Updates the dynamic DNS record for the "Master" database with the DNS provider. The DNS record is updated with the server's IP address. By default, it will use the instance's private IP address (Database Replication Network Interface = private). The default TTL of the "master" DNS record must also be set to 60 seconds or less (Database DNS TTL Limit = 60) unless you are using Rackspace's Cloud DNS service, where the lowest allowable TTL is 300 seconds.

Disable Scheduled Primary Backups

Since you have not loaded an actual database onto the server there is no reason to create a primary backup of the database.

Go to the "current" server's Scripts tab and run the db::do_primary_backup_schedule_disable operational script to disable your scheduled backups (cron jobs). 

Later, once you have imported your database you will reverse this action and enable continuous backups.

Set Up the Database

After initializing the master database server and disabling scheduled backups, you will need to add your database (or databases) and records to it.

1. Go to the "current" server's Scripts tab and run the db::do_dump_import operational script to import a MySQL dump file from an ROS location.

Note: If you use a previous backup snapshot instead of a MySQL dump file or initialize a blank MySQL database, refer to the Database Manager for MySQL 5.1/5.5 Runbook for instructions.

Create a Primary Backup

You are now ready to create the first primary backup of the database. You will need a completed backup in order to initialize a slave database server.

1. Go to the "current" server's Scripts tab and run the db::do_primary_backup operational script to manually generate a primary backup of your database server.

Enable Scheduled Primary Backups

It is now safe to enable continuous backups of the database server.

1. Go to the "current" server's Scripts tab and run the db::do_primary_backup_schedule_enable operational script.

For more information about configuring and modifying your scheduled backup policy, see the Database Manager for MySQL 5.1/5.5 Runbook.

Add a Slave Database Server

Although you can run MySQL in single-server mode and having a separate slave server for replication purposes is not required, this is strongly recommended for failover purposes. Create a slave server in your deployment.

1. Clone the Master-DB server. See Clone a Server.
2. Rename the server accordingly. (e.g. mysql-db2) Remember, you do not want to include the word "slave" in the nickname because this server may become the "master" server during a failover scenario. You don't want the server's nickname to potentially cause any confusion.
3. Under the server's Info tab, click Edit and change the server's availability zone. In order to ensure high availability, it's strongly recommended that you launch the Slave-DB server in a different availability zone as the Master-DB.  Note: Cross-zone data transfer costs may apply.

Launch the Slave Database Server

Make sure the following conditions are true before you launch the second database server.

• The master database server state is "operational."
• The initial primary backup of the master database server is 100% complete. If you are using a cloud that supports snapshots for backups, you can track the status in the dashboard (Clouds > region > Snapshots). The time required to complete the initial primary backup will vary based on factors such as storage type, volume size, etc.

You are now ready to launch a "slave" database server for failover and redundancy purposes. 

1. Go to the deployment's Servers tab and launch the server that will be the slave database server. 
2. When you view the input confirmation page, change the value for the following input because you have an operational master database server an a completed database backup. 

DB (advanced)

3. If there are any required inputs that are missing values (highlighted in red), cancel the launch and add the missing values at the deployment level before launching the server again. Refer to the instructions in Launch a Server if you are not familiar with this process.
4. Click the Launch (not Save and Launch) button at the bottom of the input confirmation page because you do not want to override this input at the server level. You may not want this server to become a slave the next time it is launched or relaunched.

The scripts perform the following actions:

• Assigns the "slave" role to the server.
• Uses the most recently completed database backup (default) to initially populate the database in order to reduce the time needed for the slave to become in-sync with the master.
• Sends a request to the master server to allow connections from the slave server's private IP address and opens the default MySQL client port (TCP port 3306) on the master server's firewall (i.e. iptables) for this purpose.
• Schedules a cron job to run primary backups of the database once per hour (default). 

(Optional) Update the DNS Record for the Slave Database Server

If you created a DNS record for the slave database server, you can set a value for the Database Slave DNS Record ID input and run the db::do_set_dns_slave operational script.

Test Database Setup (optional)

If you want to test the status of the "master" and "slave" database servers, see Check Database Status of Master or Slave.

Load Balancer Tier Setup

Create a Load Balancer

1. Go to Clouds > AWS Region > Load Balancing
2. Click Create ELB and fill out the required form fields:

General Info

• Load Balancer name - The name of our Elastic Load Balancer. It must be unique within your AWS account.
• VPC - The Virtual Private Cloud you'd like to associate to this load balancer.
• Internal Load Balancer - Select this option to create an internal load balancer. A DNS name will be created and it will contain the private IP address of the load balancer. This option is only available if you set a value for VPC.
• Subnets - Your load balancer can interface with instances in one or more subnets. Only subnets in the selected VPC are available. This option is only visible if you set a value for VPC.
• Security Groups - One or more security groups to manage traffic communicating with your load balancer. This option is only visible if you set a value for VPC.
• Availability Zone(s) - Select all of the availability zones for which the ELB will service. (Tip: Click in the box to view and select additional zones.) An ELB will only load balance across instances in the selected availability zones. An ELB is region-specific; it cannot load balance across multiple regions. For example, you cannot load balance your application traffic amongst instances in the 'us-east' and 'us-west' regions. Note: This field is not displayed if you have selected a value for VPC.

Default Listener

• LB Protocol - The routing transport protocol that will be used by the ELB. (TCP, HTTP, HTTPS)
• LB Port - External port that the ELB will listen on to accept client requests. Valid ports are 80, 443, 1024-65535.
  • For an example (v13.5 LTS) 3-tier deployment, use HTTP:80.
• Instance Protocol - The routing transport protocol that the ELB will use to connect to the instances (i.e. application servers) in its load balancing pool. (HTTP, HTTPS, TCP, SSL)  If you are using one of the application ServerTemplates (v12+) published by RightScale, select 'HTTP' for the protocol. Note: The Load Balancer and Instance Protocols must match. You can create additional listener rules after you create the ELB.]
• Instance Port - The port that the ELB will use to send traffic to the application instances. Valid ports are 1 to 65535. The Instance Port does not have to match the Load Balancer Port. If you are using one of the application ServerTemplates (v12+) published by RightScale, the default application listener port is '8000'.
  • For an example (v13.5 LTS) 3-tier deployment, use HTTP:8000.
• Stickiness - This is where you can create a session sticky policy for your load balancer (stickiness meaning that once a session starts, all requests will attempt to routed subsequent to the same server for that given session). You can select one of the following options:
  • Disable Stickiness - Does not allow session stickiness the load balancer and application server. 
  • Load Balancer Generated Cookie Stickiness - A special cookie is used to track the backend server instance for each request. When the LB receives a request, it checks to see if this cookie is present in the request. If so, the load balancer sends the request to the application server specified in the cookie. If not, the request is sent to a server chosen based on the existing load balancing algorithm. This option creates a stickiness policy with sticky session lifetime controlled by the lifetime of the browser or a specified expiration period. This only works with HTTP/HTTPS listeners.
  • Application Generated Cookie Stickiness - This is similar to the Load Balancer Generated Cookie Stickiness option, with the following exception: once a cookie is explicitly removed or expires, the session stops being sticky until a new application cookie is issued.

3. Click Save.
4. Configure the Health Check test for the ELB and click Save.

​

Add Additional Listeners (optional)

Elastic Load Balancers support both HTTP and HTTPS (SSL) requests. When you create an ELB, you must define a default listener. If you wish to set up additional listeners (e.g. HTTPS), you can configure them after the ELB is created.

Listener ports should be defined when your ELB is created. If you are setting up an ELB to load balance across applications servers launched with one of RightScale's v12.11 or v13.5 LTS ServerTemplates, you may need to modify your ELB and add additional listeners, as necessary.

1. Click on the Elastic Load Balancer you would like to modify. 
2. Check the configuration of the application ServerTemplate that will be used to launch the application servers that will connect to the ELB. Make sure that the application servers are configured to listen for requests from the ELB on the correct port. You will need to set up the listener appropriately, depending on how the application servers will be configured. (e.g. Application Listen Port (8000), LB_PORT (80), etc.)
3. To configure HTTP access, add a listener to forward requests to the appropriate port (e.g. 8000) for the application server. Click Add Listener to create a new listener for the ELB.
   • LB Protocol: Select 'HTTP'
   • LB Port: Enter '80'
   • Instance Protocol: Select 'HTTP'
   • Instance Port: Use '8000' (for v12.11 or v13.5 LTS ServerTemplates); use '8080' (for v14 ServerTemplates)
   • Stickiness: You can choose either to have stickiness disabled or generate a sticky session based on either load balancer or application generated HTTP cookies.
4. To allow HTTPS (SSL) access, add a listener to forward requests to the appropriate port (e.g. 8000) for the application servers. Click Add Listener to create a new listener for the ELB.
   • LB Protocol: Select 'HTTPS'
   • LB Port: Enter '443'
   • Instance Protocol: Select 'HTTPS'
   • Instance Port: Use '8000' (for v12.11 or v13.5 LTS ServerTemplates); use '8080' (for v14 ServerTemplates)
   • Stickiness: You can choose either to have stickiness disabled or generate a sticky session based on either load balancer or application generated HTTP cookies.
   • Certificate: Select an SSL Certificate. See Create an AWS Server Certificate.

Update the DNS Records

Once you've created your ELB, find its DNS name (e.g. elbname-12345678.us-east-1.elb.amazonaws.com) and use it to create a CNAME with your DNS provider. For an ELB, you cannot create a DNS record that points to an IP address because it could change over time.  

1. Go to the Elastic Load Balancer's Info tab in the RightScale Dashboard. 
2. Copy the "DNS name" for the ELB. (e.g. elb-name-2005463590.us-west-1.elb.amazonaws.com)

3. Create a CNAME with your DNS provider (e.g. AWS Route 53, DNS Made Easy, DynDNS, etc.)

Example: Amazon Route 53

Create a Security Group for Application Servers

The next step is to create or update a security group that will be used by application servers to allows ingress communication from an ELB. By default, RightScale's Linux-based application ServerTemplates (e.g. PHP, Rails, Tomcat) listen on TCP port 8000 and the Windows-based application ServerTemplate (e.g. Microsoft IIS App) listens on TCP port 80.

1. Create or modify a security group in the AWS region where the ELB will service requests to the application servers. Later, you will configure the application servers to use this security group in order to connect to the ELB. 
2. Create the desired port permissions. At a minimum, you will need to open up port 80 for HTTP access. You can also open up 443 for HTTPS (SSL) access. Specify the following information to create a permission for an ELB.
   • Direction: Inbound
   • Protocol: TCP - Group
   • Ports:
     • For v12.11 or v13.5 LTS ServerTemplates, use 8000..8000 (PHP, Rails, Tomcat, Django); 80..80 (Microsoft IIS)

     • For v14 ServerTemplates, use 8080..8080 (PHP, Rails, Tomcat, Django); 80..80 (Microsoft IIS)

   • Owner: amazon-elb
   • Group: amazon-elb-sg

Application Tier Setup

Prepare Application Code

PHP App Server (v14 Infinity) - Tutorial

Sample Application

If you need an example application for testing purposes, you can use the application code from the following git repository.

• Account Credential - Set to "Inherit: No value to inherit" because the sample application is located in a 'public-read' repository.
• Repository Provider - repo_git
• Repository URL/ROS Container - git://github.com/rightscale/examples.git
• Repository Branch/Tag/Commit - unified_rails

Add a Server

Follow these steps to add an application server to the deployment.

1. Go to the MultiCloud Marketplace (Design > MultiCloud Marketplace > ServerTemplates) and import the most recently published revision of the following ServerTemplate into the RightScale account.
   • Apache-Rails-Passenger App Server (v13.5 LTS)
2. (Optional) If you expect to make changes to the ServerTemplate, you will need to clone it to create an editable copy.  Click the Clone button and rename the ServerTemplate accordingly. (e.g. My App Server) Before you make any changes to the ServerTemplate, click the Commit button so that the first revision of the ServerTemplate matches the original revision, which will make it easier to perform differentials in the future to see what changes were made to the "original" version. When committing the ServerTemplate you can use a simple commit message. (e.g. Original version. No changes.) If you are actively developing the ServerTemplate, you may find it useful to use the HEAD version of the ServerTemplate to create the application server tier. However, for production environments, you should always use static, committed revisions of a ServerTemplate to launch servers.
3. From the imported ServerTemplate's show page, click the Add Server button.
4. Select the cloud for which you will configure a server. 
5. Select the deployment for the new server.
6. Next, the Add Server Assistant wizard will walk you through the remaining steps that are required to create a server based on the selected cloud.
   • Server Name - Provide a nickname for your new database server (e.g., mysql-db1). Do not include "master" or "slave" in the name, because a database server's role can change in the future.
   • Select the appropriate cloud-specific resources (e.g. SSH Key, Security Group, etc.) that are required in order to launch a server into the chosen cloud. The required cloud resources may differ depending on the type of cloud infrastructure. If the cloud supports multiple datacenters/zones, select a specific zone. Later, when you create the other database server you will use a different datacenter/zone to ensure high-availability. For more information, see Add Server Assistant.
   • Important! If you are not using volumes to store the database, you must select an instance type that has disk space that's at least twice as large as your database because LVM snapshots are performed locally on the instance before they are gzipped and saved to the specified ROS location. Also, although these ServerTemplates will work with any instance size, you may experience degraded performance with small instance sizes (such as EC2 micro, Rackspace 256MB etc) due to lack of system resources. We do not recommend smaller instance types for production use.
7. Click Confirm, review the server's configuration and click Finish to create the server.
8. If you are setting up a multi-tier deployment, it's strongly recommended that you create at least two application servers for high availability purposes.
   • The easiest way to create the second server is to clone the first one. Be sure to change the name of the server accordingly (e.g. app2) and its availability zone (if available) under the the Info tab. You can either add application servers directly into a deployment or create an server array of application servers for autoscaling. 

Configure Inputs

The next step is to define the properties of your application server by entering values for inputs. It is best to do this at the deployment level. For a detailed explanation of how inputs are defined and used in Chef recipes and RightScripts, see Inputs and their Hierarchy.

To enter inputs for the Chef recipes that will run on your application servers, open the deployment's Inputs tab and click Edit, then follow the directions below to configure input values. We recommend that you set up credentials for password values and any other sensitive data as shown in the examples.

Note: Some inputs referenced in this tutorial are considered "advanced" are not initially displayed in the Dashboard. If you are unable to find an input in the Dashboard, be sure to use the "Show advanced inputs" option to view all related inputs of a particular input category.

Important! The ServerTemplate supports multiple configuration permutations. Read each input description carefully. You must provide appropriate values depending on your chosen configuration.

APP

APP_PASSENGER

To set other inputs related to a Rails Passenger application, expand out the "Advanced Inputs" section to change any of the default values.

DB

LB

REPO

The values that you use for the repository inputs will depend on where the application code will be retrieved from. The selection for the Repository Provider input will determine which inputs will be used to retrieve the application. Unrelated inputs are ignored.

-ALL Repositories (ROS, Git, SVN, FTP)

The following inputs are used to retrieve the application from either a Git/SVN software repository or an ROS location. Specify the appropriate inputs based upon the selection for the 'Repository Provider' input.

Git Repository

Important!
If you are checking out code from a Git repository, specify values for the following inputs.

SVN Repository

Important!
If you are checking out code from a SVN repository, specify values for the following inputs.

Remote Object Storage (ROS)

Important!
If you are checking out code from a Remote Object Storage (ROS) location, specify values for the following inputs.

WEB_APACHE

Launch the Server

After configuring your inputs, launch all of the Rails application servers. Refer to the instructions in Launch a Server if you are not already familiar with this process.

Test the Deployment

Next Steps

Set up an Autoscaling Application Tier

To replace the static application servers in the deployment (under the deployment's Servers tab) with a scalable server array for dynamically autoscaling the application tier, follow the Add a Scalable Application Server Array to a Deployment tutorial.

Safely Shutdown the Servers

If you completed the tutorial for testing purposes and no longer need the running servers, follow the steps below to safely shutdown the deployment.

1. Delete or change the DNS A records that point to the ELB load balancing service.
2. Delete the Elastic Load Balancer.
3. Terminate the Master and Slave Database Servers. (If you are using volumes, see the Database Manager for MySQL 5.1/5.5 Runbook for proper instructions.)
4. Terminate the application servers.
5. Delete the deployment if you do not plan to relaunch the servers in the deployment again.