AWS Spot Instance Availability Zones

Question

I'm trying to run an AWS Instance for as cheap as possible and I can see from the pricing history that in availability zone us-east-1d the current price is at $0.25 but in us-east-1a the price is $9.60.

I put in a request for $0.3 and it's saying my request is lower than the minimum fulfillment price of $9.60. There was nowhere to specify the availability zone in the request wizard but there must be a way to get it cheaper than $9.60 which is way over the on-demand price!

Am I doing it wrong somehow or is there a way to do this?

Edit: added image of wizard, where's the option to specify availability zone?

Answer 1

On step 3 you should have the option to set your availability zone preference. Default option is "No Preference".

Answer 2

Faced the same question recently, AWS spot instance wizard is not very intuitive in this regard.

My case was a default VPC, the same as is in the initial question. Therefore to "select availability zone" one needs just to select a corresponding subnet from drop down field.

The official AWS documentation states:

Launching Spot Instances in an Availability Zone Group

Specify an Availability Zone group in your Spot Instance request to tell the Spot service to launch a set of Spot Instances in the same Availability Zone. Note that the Spot service need not terminate all instances in an Availability Zone group at the same time. If the Spot service must terminate one of the instances in an Availability Zone group, the others remain running.

Note that although this option can be useful, adding this constraint can lower the chances that your Spot Instance request is fulfilled.

If you specify an Availability Zone group but don't specify an Availability Zone in the Spot Instance request, the action taken by the Spot service depends on whether you specified the EC2-Classic network, a default VPC, or a nondefault VPC. For more information about EC2-Classic and EC2-VPC, see Supported Platforms.

EC2-Classic

The Spot service finds the lowest-priced Availability Zone in the region and launches your Spot Instances in that Availability Zone if the lowest bid for the group is higher than the current Spot Price in that Availability Zone. The Spot service waits until there is enough capacity to launch your Spot Instances together, as long as the Spot Price remains lower than the lowest bid for the group.

Default VPC

The Spot service uses the Availability Zone for the specified subnet, or if you don't specify a subnet, it selects an Availability Zone and its default subnet, but it might not be the lowest-priced Availability Zone. If you deleted the default subnet for an Availability Zone, then you must specify a different subnet.

Nondefault VPC

The Spot service uses the Availability Zone for the specified subnet.