Recent Posts with AWS Instances tag

Amazon is a huge player in the cloud hosting space. Cloud hosting is basically where a company fills a server farm with racks upon racks of physical computers, hard drives and routers. The company then uses software to combine the individual computers into a super computer which is then partitioned off into a series of virtual servers of varying sizes and types. The company then resells usage of these virtual servers to their clients. Amazon Web Services (the division which provides the service) offers a variety of different types of virtual servers, but the basic, and most flexible, is called Elastic Cloud Compute (EC2).

Amazon EC2

Instances

Instances can be thought of as the virtual processor, motherboard and RAM of the virtual server. Amazon offers three different types of Instances (On-Demand, Reserved, and Spot) and of varying different sizes.

On-Demand Instances

On-demand Instances are those you intend on using on a temporary basis. You are paying only for the amount of time you actually use the instance, so they are excellent for short-term projects and to get settings worked out.

Reserved Instances

Reserved Instances are instances which are dedicated to your account. They do not go away if you stop, or terminate them. Well, that is not quite correct. You are actually reserving usage of a particular type of instance, rather than a particular instance. The different levels of Reserved Instances are basically usage structures. You prepay to reserve an instance and in exchange get a discount on the hourly rate. Reserved Instances are ideal for long-term server applications, like website host, email servers, etc.

Reserved Instances Utilization Rates

• Heavy Utilization - These instances are used 80%+ of the month.The core website and email servers.
• Medium Utilization - These instances are used for 40-79% utilization rates. If you run a few heavy traffic websites, then these instances would be the load-balanced servers to support demand during peak times like the evenings and weekends.
• Light Utilization - These instances are used for 17-30% utilization rates. This time frame corresponds really well with development servers that are started in the morning, run for 7-8 hours then turned off in the evening.

Spot Instances

Spot Instances are similar to on-demand instances, but are designed for special project type circumstances. Amazon obviously wants to keep all of their servers running all the time (ie. 100% utilization), however with the on-demand type structure, there are times when some servers are not being used. During these low slow times, Amazon would rather sell time on them temporarily for a discount rather than let them run empty. These temporary discounted servers are the spot instances. Spot instances work really well for periodically maintenance activities. To use a spot instance, you indicate the size of instance and the maximum price you bid for usage of that instance. Once the price for that size of instance goes below the bid price, the instance starts up and you get it until the prices goes back over your max bid price. Note you are only charged the actual price, not your bid price, so you can often pay less per hour than your bid price for spot instances.

EC2 Resources

Elastic Block Store Volumes

Elastic Block Storage (EBS) volumes are the virtual hard drives of the virtual server. There are two types of EBS Volumes, Standard and Provisioned  IOPS (Input/output Operations Per Second).

Standard EBS Volumes

Standard EBS volumes correspond the best to physical media hard disks. You can read and write to them at average rates and deliver about 100 IOPS. Unless you need high writing/ reading capabilities, a standard EBS is what you'd use.

Provisioned IOPS Volumes

Provisioned IOPS are for high read/write type situations. The most common examples is a database server. These volumes are very powerful, but also very expensive (relatively). There are other AWS Services offered, like S3, SES and RDP, but I currently don't use them some will avoid going into detail on those services until I use them.

Amazon AWS is currently offering a 'free tier' for 1 year. Simply you get a micro instance to get your server up and running, play with different settings and such. It is the standard free trial offer, but with a virtual server. If you've never used AWS before, I recommend using the free tier server to get acquainted with the capabilities of AWS then move to a real server later. Also, once you have all the settings working on the free tier instance, you can transfer to paid instance in 15 minutes. AWS Free Tier

• 750  hrs/month Micro instance (613 MB of RAM, Linux or Windows)
• 750 hrs/month Elastic Load Balancer (15 GB of data processing)
• 30GB of EBS space
• 5 GB of Amazon S3 standard storage

Setting up a New Instance

1. Go to and login to your .
2. Click on "EC2" under the Compute & Networking section. (Note you may have to choose your region at this point if it hasn't been setup yet.)
3. At the "Amazon EC2 Console Dashboard" there should be a button in the middle of screen called "Launce Instance", Click it.
4. The wizard will pop-up asking you to choose a type of wizard. Select "Class Wizard" and click "Continue" at the bottom right.
5. Select the "Amazon Linux AMI ####.##"  AMI. It should be the top option under the "Quick Start" tab. Note, you can use any of the AMIs with a yellow star next to the select button for the free tier. The 32-bit version will be slightly easier to deal with later, but 64-bit version works just fine also.
6. You will now need to determine the basic instance details. For the free tier, make sure the "Number of Instances" is set to 1 and the "Instance Type" is "Micro  (t1.micro, 613 MiB)". The "Availability Zone" doesn't matter right now so "No Preference" is fine. Click the "Continue" when the settings are correct.
7. You now can determine some of the advanced options. The only thing you need to be concerned about is the "Shutdown Behavior" which should be set to "Stop". Click the "Continue" when the settings are correct.
8. The next page is a the storage details. New instances default to a "Root Volume" which is effectively a new blank standard EBS volume.I recommend you uncheck the "Delete on Termination" checkbox to prevent you from accidentally erasing your data when the instance dies.Click the "Continue" when the settings are correct.
9. Now you can set metadata you want to correspond with this instance. These key/value pairs will help with searching and administrating large clouds of multiple servers. In addition to the "Name" key, we generally always place a "admin" key with the value equaling the programmer who administrates the instance. You can place up to 10, and you can always change them later. Enter something for the "Name" key's value then press "Continue".
10. The next step is absolutely essential to run a secure instance and have access via an SSH client. Instead of using usernames and passwords, AWS uses usernames and encryption keys, called "Key Pairs." This encryption level prevents brute force attacks against your instance. Enter a name (alphanumeric without spaces) then press the "Create and Download your Key Pair" button. You will be expected to save the key file somewhere on your locale computer; remember where because you will need this file later when setting up your SSH and SCP clients. Click "Continue" once you have created your Key Pair.
11. The last setting you need to determine is the firewall. Amazon allows you to create an off-instance firewall to limit access to your instance. Click on the "Create a New Security Group" radio button then enter a "Group Name" and "Group Description". Leave the the "Inbound Rules" empty for now. Typically when you create an instance, you will you use a pre-created security group that you already setup for the purpose of the instance.  Click "Continue" once the new security group is created.
12. This last page is just a review of the settings for your new instance. Look over them and make sure everything is correct then click "Launch." A few moments later your simple Free Tier instance will be up and running. The next step is getting access to it, then installing software and configuring everything. These will be discussed in future posts.