Switch my frontends to use EIastic IPs

Migration Instructions - Summary

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

1. Create Elastic IPs for your frontend servers.  See Create Elastic IPs (EIP).
2. Launch new servers using the appropriate frontend ServerTemplate that is using the latest RightImage^TM
3. Connect the new EIP frontend servers to the running application servers.
4. 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.
5. Change the DNS A records for your two frontends to point to the new EIP frontend servers.
6. Once no more requests are being served from the old frontend servers, terminate them.

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 (EIP) addresses that you can later assign to your frontend servers, follow the Create Elastic IPs (EIP) tutorial and register two Elastic IPs.  You will need an EIP for each frontend server.

Step 2:  Launch new frontend servers using the most recent frontend ServerTemplates

Select the appropriate RightScale frontend ServerTemplate (PHP FrontEnd, Rails FrontEnd, etc.).

1. Add a Server to your Deployment with the appropriate server information.  Select the first Elastic IP (e.g. fe-1) that you want to associate with the first frontend.  Click Add.
   
    
2. Repeat the process for the second frontend server and select the other Elastic IP (e.g. fe-2).
3. Launch the new servers. 
4. 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 RightScript.  The new frontend servers will try to get the configuration file from the running frontend servers.  Once they get the configuration 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 RightScript.

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

The new EIP frontend servers are now ready to serve traffic.  With your DNS provider, lower the TTL on the A records that point to your frontend servers so that the change will be propagated more quickly.  Wait a couple of minutes and then 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.