Switch my frontends to use EIastic IPs

1. Migration Instructions

In the July 15, 2008 release of the RightScale Dashboard, all server templates were updated to use the latest RightImage v3 AMI (RightImage CentOS5_0V3_0_0). The frontend server templates were also updated to use Elastic IPs (EIP) instead of using the Dynamic DNS IP addresses using DNSMadeEasy. To understand the benefits of using Elastic IPs for your frontend servers, see "Why should I use Elastic IPs?"

If you have running frontend servers that are using DNSMadeEasy for configuring their dynamic IP addresses and wish to switch to using an Elastic IP instead, you will need to follow the migration instructions below in order to ensure that your visitors do not experience any problems connecting to your site. If you do not take the necessary steps when changing the IP addresses of running frontend servers, your users could experience a sudden interruption of service and bad server requests as you suddenly switch to using Elastic IP addresses.

Migration Instructions

In order to follow best practices when switching to Elastic IP addresses you must follow the necessary precautionary steps.

Create Elastic IPs for your frontend servers. See Create Elastic IPs (EIP).
Launch new servers using the appropriate frontend server template that is using the latest RightImage (RightImage CentOS5_0V3_0_0).
Connect the new EIP frontend servers to the running application servers.
Connect the new EIP frontend servers to each other.
NOTE: This step only applies to Basic Setups because in this scenario, frontends are also running application servers.
Change the DNS A records for your two frontends to point to the new EIP frontend servers.
Once no more requests are being served from the old (DNSMadeEasy) frontend servers, terminate the servers.

Sample Setup Diagrams

Below are diagrams of two common setups. The Basic Setup is a 4-instance deployment where the frontends serve as both the load balancer and application server. In the Advanced Setup, the frontends are strictly load balancers that point to all of the application servers.

Step 1: Create two Elastic IPs for your frontend servers.

If you have not reserved Elastic IP addresses for your front end servers, follow the Create Elastic IPs (EIP). tutorial and register an EIP for each frontend server.

Step 2: Launch new frontend servers using the most recent frontend server templates

Select the appropriate RightScale frontend server template (PHP FrontEnd, Rails FrontEnd, etc.).
Add it to your running deployment with the appropriate server information.
Repeat the process for the second frontend server and select the other Elastic IP (ex: fe2).
Launch the new servers.
Once the servers are operational, continue to the next step.

Step 3: Connect the new EIP frontend servers to the running application servers

The next step it to connect the new EIP frontend servers to the running application servers by executing the LB get HA proxy config operational action. The new frontend servers will try to get the config file from the running frontend servers. Once they get the config file, they can route traffic to the application servers.

Step 4: Connect the new frontends to each other

NOTE: This step only applies to the Basic Setup. For Advanced Setups, skip to the next step.

Since the frontend instances are also running the application servers, you'll need to associate the new frontends together by running the LB mongrels to HA proxy connect operational action.

Step 5: Change the DNS A records to point to the Elastic IPs

The new EIP frontend servers are now ready to serve traffic. Change the DNS A records to point to the new EIP frontend servers so incoming traffic will be routed to the frontends.

Step 6: Terminate old frontend servers

Once no more requests are being handled by the old frontend servers (FE-1, FE-2), you can safely terminate the instances. You can find information about HAproxy and Apache activity in the monitoring graphs. We recommend leaving the old frontend servers running for a couple of days to make sure everything is running properly, because if you experience any problems, it will be easy to switch back to the old frontends.