How many EC2 instances can be used within Amazon VPC?

Question

Amazon's Virtual Private Cloud (Amazon VPC) allows me to open a VPN connection to the EC2 cluster.

It looks like the number of EC2 instances you can run within a virtual private cloud is 24 hosts - is that correct?

Answer 1

Update

The beta limitations mentioned in the initial answer have meanwhile been lifted, the new ones (which can be raised as outlined) are addressed by the respective FAQ How many Amazon EC2 instances can I use within a VPC?:

You can run any number of Amazon EC2 instances within a VPC, so long as your VPC is appropriately sized to have an IP address assigned to each instance. You are initially limited to launching 20 Amazon EC2 instances per VPC at any one time and a maximum VPC size of /16 (65,536 IPs). If you would like to exceed these limits, please complete the following form.

Furthermore, the initial Number of VPCs per region is 5 and the initial Number of subnets per VPC is 20, see Appendix B: Limits for details regarding these and other limitations in place.

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Initial Answer

You can currently have 1 VPC per AWS account with up to 20 subnets. These are the beta limitations, complete their form if you need to lift them.

There is also a limit of instances you can run with a single AWS account, but again -- you can get them to up this limit. AWS has all kinds of limits in place, also on EBS volumes, elastic IPs, etc.. They can all be upped.

Answer 2

I highly doubt it. My understanding is that VPC is just a VPN, where you can tunnel as much traffic as it can support through the pipe. Are you confusing hosts with subnets? There is a restrictions on the number of subnets available. There is also a restriction on the number of hosts (I think it's a max of 20 hosts), but that's a general EC2 concern and not specific to VPC. Note that both restrictions can be overturned if you send an email to Amazon.

Answer 3

Things Have Changed.

Q: How many instances can I run in Amazon EC2?

You are limited to running up to 20 On-Demand instances, purchasing 20 Reserved Instances, and requesting Spot Instances per your dynamic Spot limit per region. New AWS accounts may start with limits that are lower than the limits described here. Certain instance types are further limited per region as follows...

Source: http://aws.amazon.com/ec2/faqs/#How_many_instances_can_I_run_in_Amazon_EC2

Answer 4

It depends on the type of the instance. Check your limits using the following instruction: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-resource-limits.html