Learn how to create a highly available distributed application in the cloud in just 3 simple steps.

1. How-To: Architect for High Availability in the Cloud
Set Up an HA App in the Cloud in 3 Steps
August 20, 2014
© 2014 GoGrid

2. What is a highly available distributed application?
 Definition
 High availability (HA) refer to the availability of the application cluster
 HA also refers to the ability to failover or scale horizontally as needed
 Use Cases
 Database applications
 File-sharing networks
 Social applications
 Health monitoring applications
 eCommerce websites
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© 2014 GoGrid

3. Set up an HA app in the cloud in just 3 steps
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© 2014 GoGrid
 Step 1: Decide What Application Architecture You Need
 Distribute the application across multiple servers: This approach lets you
balance traffic and scale out the web front end as needed.
• In GoGrid, you can do this for free using our Dynamic Load Balancers.
Point and click to provision the servers as needed, and then point the
load balancer(s) to those servers. The process is simple, so setting up a
load-balanced web front end should only take a few minutes.

4. Set up an HA app in the cloud in just 3 steps (cont’d)
 Deploy the Cassandra cluster: In GoGrid, you can use our 1-Button Deploy™
technology to set up the Cassandra cluster for your database in about 10
minutes. Cassandra is built to be HA so if one server fails, the load is
distributed across the cluster and your application isn’t impacted.
• Below is a sample Cassandra cluster. A minimal deployment has 3
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nodes to ensure HA and the cluster is connected via the private VLAN.
It’s a good idea to firewall the database servers and eliminate
connectivity to the public VLAN. Your database and web application
clusters will look something like this:
© 2014 GoGrid

5. Set up an HA app in the cloud in just 3 steps (cont’d)
 Step 2: Plan for Multi-Cloud (3 Components):
1. Create a multi-cloud backup strategy: Employing a multi-cloud backup
strategy simply means not putting all your eggs in one basket. Take the
time to create relationships with multiple providers and store your
backups on multiple clouds. Even if you don’t distribute your workloads
across multiple providers, distributing your backups and archives across
providers can ensure you can recover from a catastrophe, if necessary.
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© 2014 GoGrid

6. Set up an HA app in the cloud in just 3 steps (cont’d)
2. Use standard architectures and deployment tools: Recovering from an
incident becomes much harder if you’re working with tools that aren’t
consistent across providers or proprietary services. If you are, you can still
distribute your backups and recover: One alternative is to set up Cassandra
with Hadoop on AWS and also set up Cassandra with Hadoop on GoGrid
using the same out-of-the-box application technology. This way, you don’t
have to re-invent the wheel for each cloud provider with which you’re
engaged.
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© 2014 GoGrid

7. Set up an HA app in the cloud in just 3 steps (cont’d)
3. Design for failover scenarios across providers: There are a few reasons
you may want to direct traffic to alternate locations: to optimize
performance, deliver custom content to a specific region, or failover.
Geographic Load Balancing lets you direct the traffic for your websites to
the servers or data centers closest to visitors based on their geographic
location. Adding failover capabilities provides a mechanism for continuous
availability in the case of a cluster or data center failure.
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© 2014 GoGrid

8. Set up an HA app in the cloud in just 3 steps (cont’d)
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© 2014 GoGrid
 Step 3: Design to Scale Out
 This is the area where the true value of a cloud provider comes into play. As
this figure shows, leveraging cloud infrastructure, you can scale out nodes,
servers, databases, load balancers, firewalls, and storage in multiple
locations, ensuring your operation is healthy and can recover easily in the
event of disaster.

9. What is a highly available distributed application?
 Conclusion
 And that’s it. In a few simple steps, you can ensure your architecture is HA.
Just keep in mind that you need to build 3 things:
1. A distributed, fault-tolerant application architecture
2. A multi-cloud strategy for disaster recovery and failover
3. A design that enables the ability to scale out across data centers and
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providers
 Learn More
 This “how-to” is based on a blog post by Kole Hicks, GoGrid’s Senior Director
of Product Management:
http://blog.gogrid.com/2014/07/22/architecting-high-availability-cloud/
© 2014 GoGrid