AWS EC2 CLI -> How to get list of avaliable instances

Question

Good day time, profs. I am a bit new to aws cli framework. What i need to get via console is a list of available instances in a specified region with a limit number of that type.

For example, command should look like:

aws ec2 describe-available-instances --region us-west-1 --type [t1.micro, c3.4xlarge, etc. If not set - list all types] 

and the output will look like:

---

t1.micro 5

c3.4xlarge 10

m4.4x 20

---

Answer 1

You can achieve this output as JSON with AWS CLI and JQ.

Step by step:

1) Call the describe-instances command. This retrieves all sorts of metadata about an EC2 Instance, including the Instance Type. We will eventually filter our output down to Instance Type alone.

aws ec2 describe-instances

2) Specify an instance-type filter via the --filter param. If this is not specified, this query will display all instance types where count > 0. This will not include 0-count types because the output is derived from your collection of EC2 instances.

--filters "Name=instance-type,Values=t2.micro,t2.small"

3) Specify a region via the --region param. If this is not specified, AWS CLI will attempt to use your default region.

--region us-east-1 

4) Specify your query. Output an array of key/value pairs where Key = "InstanceType", Value = InstanceType.

--query "Reservations[].Instances[].{InstanceType:InstanceType}"

5) Use jq to group by Instance Type, so that like-InstanceTypes will be aggregated.

| jq "group_by(.InstanceType)

6) Map a final array of key/value pairs, where key = InstanceType and value = jq length, or in other words the sum of each group of instance types.

| map({(.[0].InstanceType):length})

Full Example:

aws ec2 describe-instances --region us-east-1 --filters "Name=instance-type,Values=t2.micro,t2.small" --query "Reservations[].Instances[].{InstanceType:InstanceType}" | jq "group_by(.InstanceType) | map({(.[0].InstanceType):length})"

Output:

[
  {
    "t2.micro": 12
  },
  {
    "t2.small": 2
  }
]

---

Additional Notes

If you're trying to retrieve the Amazon GameLift per-instance-type limits, use describe-ec2-instance-limits:

aws gamelift describe-ec2-instance-limits --query 'EC2InstanceLimits[].{EC2InstanceType:EC2InstanceType,InstanceLimit:InstanceLimit}' --region us-east-1 --output text

Further Reading

• AWS Documentation - aws gamelift describe-ec2-instance-limits
• AWS Documentation - aws ec2 describe-instances
• AWS Documentation - Controlling Command Output from the AWS Command Line Interface
• JQ - Builtin operators and functions

Answer 2

With purpose see all instances without filters - use this:

aws ec2 describe-instances --output text \
--query 'Reservations[*].Instances[*].[InstanceType]' | sort | uniq -c

Output will look like this:

1 m3.medium
1 m4.10xlarge
9 m4.xlarge
6 t2.large
5 t2.medium
4 t2.micro
2 t2.xlarge

And with purpose to filter by specific type - just add filter, like this:
--filters "Name=instance-type,Values=t2.micro,t2.small", your comand will look like this:

aws ec2 describe-instances --output text \
--filters "Name=instance-type,Values=t2.micro,t2.small" \
--query 'Reservations[*].Instances[*].[InstanceType]' | sort | uniq -c