[LINUX] Change AWS EC2 instance from t2 to t3

At first

I think it's okay to just change the instance type for a relatively new instance, but it is possible that the old one does not support ENA. That's exactly what I wanted to change this time. The OS was CentOS 7 series, but it was a little old, so it did not support ENA. So, we will start with ENA support.

About ENA https://docs.aws.amazon.com/ja_jp/AWSEC2/latest/UserGuide/enhanced-networking-ena.html

ENA compliance confirmation

modinfo ena

If not supported

modinfo: ERROR: Module ena not found.

Seems to come out

update CentOS can be updated with yum to support ENA

sudo yum update

This time it was an old instance, so update failed. In that case, comment out the mirror of the repo information and enable baseurl.

Instance restart

aws ec2 reboot-instances --instance-ids {InstanceID}

ENA compliance confirmation

modinfo ena

It should be displayed in various ways unlike the previous one.

ENA activation

You need to shut down the instance for ENA to take effect.

#Stop the instance
aws ec2 stop-instances --instance-ids {InstanceID}
#Check if ENA is valid
aws ec2 describe-instances --instance-ids {InstanceID} --query "Reservations[].Instances[].EnaSupport"

It's not enabled at this time, so it will probably return [].

#ENA activation
aws ec2 modify-instance-attribute --instance-id {InstanceID} --ena-support
#Check if ENA is valid
aws ec2 describe-instances --instance-ids {InstanceID} --query "Reservations[].Instances[].EnaSupport"

With confirmation here

[
    true
]

Is OK when

Change to t3

Finally change to t3

#Change
aws ec2 modify-instance-attribute --instance-id {InstanceID} --attribute instanceType --value t3.{InstanceSize}
#Start-up
aws ec2 start-instances --instance-ids {InstanceID}

It seems that I was able to change it safely.