106 votes

What Linux distribution is the Amazon Linux AMI based on?

Instead of guessing which version of RHEL a particular distro is based off, just run: rpm -E %{rhel} For Amazon Linux 2, this will give you 7.
Danila Vershinin's user avatar
93 votes
Accepted

How to install Docker on AWS EC2 instance with AMI (CE/EE Update)

To get Docker running on the AWS AMI you should follow the steps below (these are all assuming you have ssh'd on to the EC2 instance). Update the packages on your instance [ec2-user ~]$ sudo yum ...
ajtrichards's user avatar
  • 1,054
86 votes
Accepted

How to determine AWS security group dependencies?

Paste the security group ID in the "Network Interfaces" section of EC2. This will find usage across EC2, EB, RDS, ELB. CLI: aws ec2 describe-network-interfaces --filters Name=group-id,Values=sg-...
Denys Stroebel's user avatar
70 votes
Accepted

Download SSL certificate from aws certificate manager

You cannot download a SSL certificate from ACM.
ceejayoz's user avatar
  • 33.2k
58 votes

How to change an EC2 instance's security group

Now you can change the security group of an EC2 instance from the web console itself. Select an instance -> right click or click Actions -> Under Networking -> select Change Security Groups
Slartibartfast's user avatar
50 votes
Accepted

How to know if a machine is an EC2 instance

First, I felt the need to post a new answer because of the following subtle problems with the existing answers, and after receiving a question about my comment on @qwertzguy's answer. Here are the ...
Josh Kupershmidt's user avatar
48 votes
Accepted

How to convert a unencrypted EBS to be encrypted

It's possible to copy an unencrypted EBS snapshot to an encrypted EBS snapshot. So the following process can be used: Stop your EC2 instance. Create an EBS snapshot of the volume you want to encrypt. ...
Matt Houser's user avatar
  • 10.2k
43 votes

Cannot SSH: debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY

In my case, I have no permission to lower the MTU size. And manually specifying the Cipher does not work. I am able to connect after shortening the MACs list by specifying one, e.g.: ssh -o MACs=...
Lacek's user avatar
  • 558
41 votes
Accepted

In AWS, how to check which resources are using VPC IP addresses

In the EC2 console, in the navigation pane on the left, click Network Interfaces. Everything with an IP address -- EC2 instances, ELBs, NAT Gateways, RDS instances (to name some of the more common ...
Michael - sqlbot's user avatar
38 votes
Accepted

How to make EC2 user data script run again on startup?

rm /var/lib/cloud/instances/*/sem/config_scripts_user Confirmed working on: CentOS 7.4 Ubuntu 14.04 Ubuntu 16.04 For the sake of completeness, if you have a situation where you care to keep track ...
Mike Conigliaro's user avatar
38 votes

Elastic Beanstalk stuck for more than 12 hrs

If you know how to fix the source of problem (for example: change application settings in Beanstalk Environment variables or deploy fixed version of your application), then: Go to page Auto Scaling ...
Alexey Vazhnov's user avatar
35 votes
Accepted

How do I ensure my AWS free tier plan doesn't exceed the free usage limit?

You can't set a limit on AWS spending. AWS doesn't have a limit function - it's not in their interest, even though they do quite well at putting the customers first and trying to help the customer ...
Tim's user avatar
  • 32.7k
34 votes

What is "freeable memory"?

It is basically available RAM. See answer from AWS here https://forums.aws.amazon.com/thread.jspa?threadID=209720 and the official documentation is here http://docs.aws.amazon.com/AmazonRDS/latest/...
AstroTom's user avatar
  • 687
34 votes
Accepted

What Linux distribution is the Amazon Linux AMI based on?

There's a discussion thread available over on the AWS forums that indicates the officially supported Amazon Linux AMI is not based upon any Linux distribution. Rather, the Amazon Linux AMI is ...
Trevor Sullivan's user avatar
34 votes

amazon linux 2 ami - aws - How to install mysql in Amazon Linux 2?

I got the answer myself. Follow the below steps: sudo wget https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm sudo yum localinstall mysql57-community-release-el7-11.noarch.rpm ...
Jey Geethan's user avatar
32 votes
Accepted

How to add a Tag when launching an ec2 instance using aws clis

As of 28 March 2017, you can specify tags for instances (and attached volumes) as part of the run-instances command. Example: aws ec2 run-instances --image-id ami-abc12345 --count 1 \ --instance-...
TylerW's user avatar
  • 596
32 votes
Accepted

How to install Certbot on Amazon Linux EC2

For EC2 running Amazon Linux 2 AMI: Enable EPEL Repo: sudo amazon-linux-extras install epel Install Certbot: sudo yum install certbot-apache
Wu Haa's user avatar
  • 436
31 votes
Accepted

How to find out an ec2 instance's private and public IP via aws cli?

Generally you can do it with --query filter. If you need the private IP address only: aws --region YOUR-AWS-REGION \ ec2 describe-instances \ --filters \ "Name=instance-state-name,Values=running" \ "...
Peycho Dimitrov's user avatar
30 votes
Accepted

Fundamental difference between t3 and t3a EC2 instances

Per benchmarks at photographerstechsupport.com, t3 instances tend to be 10 to 20% faster than their equivalently spec'd t3a counterparts. I notice that the precision of some of the benchmark values is ...
HumanJHawkins's user avatar
29 votes
Accepted

How to choose best EC2 instance for the system

It's easy to change the instance types up, down, or sideways. Don't try to guess which one will work the best for you - instead test it out. If you've got t3a.medium now try upgrading to t3a.large. Or ...
MLu's user avatar
  • 25.4k
29 votes

What is a secure and user-friendly way to provide only a few users access to web app on Amazon EC2?

Option 4 - stop controlling the access through Security Groups and instead implement some decent authentication mechanism. For example put an Application Load Balancer in front of the web app and ...
MLu's user avatar
  • 25.4k
28 votes

xvda1 is 100% full, What is it? how to fix?

I know i am replying in this thread after nearly 5 years but it might help someone, I had the same problem, i had m4.xlarge instance df -h told that the /dev/xvda1 was full, - 100% Filesystem ...
Swat's user avatar
  • 475
28 votes

Deny IP address on AWS ELB

A straight forward solution is to use a VPC Network ACL Inbound Rule. This only works if your ELB is in a VPC, but if you've created it in the last few years it should be in the default one. To ban 1....
Tama's user avatar
  • 381
28 votes

What Linux distribution is the Amazon Linux AMI based on?

Seems like it's based on RHEL: $ cat /etc/os-release NAME="Amazon Linux AMI" VERSION="2017.09" ID="amzn" ID_LIKE="rhel fedora" VERSION_ID="2017.09" PRETTY_NAME="Amazon Linux AMI 2017.09" ANSI_COLOR="...
todd_dsm's user avatar
  • 525
26 votes
Accepted

How do I update the Nginx configuration file on many identical servers at the same time?

There are a number of concepts that you can leverage. The key to success is automation First option is to keep doing what you're doing now, i.e. rebuild the EC2s with every configuration change. ...
MLu's user avatar
  • 25.4k
25 votes
Accepted

Do CPU credits exist for c5d.large instances? And if not, why not?

CPU credits only apply to T2/T3 instances. Each T2/T3 instance accumulates some CPU credits per second and also when it's in use (i.e. not "idle") it spends these CPU credits. When it runs out of ...
MLu's user avatar
  • 25.4k
24 votes

Why does my OpenSSH key fingerprint not match the AWS EC2 console keypair fingerprint?

If you only have public keys, you can generate the AWS fingerprint as follows: ssh-keygen -e -f id_rsa.pub -m pkcs8 | openssl pkey -pubin -outform der | openssl md5 -c
J. Doe's user avatar
  • 391
23 votes

How do I access the attached volume in Amazon EC2

To use a EBS volume attached in the EC2, you need first mount the volume. Connect to your instance using SSH. Use the lsblk command to view your available disk devices and their mount points. [ec2-...
Renato Coutinho's user avatar
23 votes

How to get Autoscaling group Instances IP adresses

As alternative, my version without any jq/awk/sed/cut $ aws autoscaling describe-auto-scaling-instances --region us-east-1 --output text \ --query "AutoScalingInstances[?AutoScalingGroupName=='ASG-...
ALex_hha's user avatar
  • 7,303
23 votes
Accepted

AWS EC2 deny single ip address and allow all

The only way to deny sources/IP addresses is to use Network ACL's in the VPC. These operate like a firewall allowing or blocking traffic incoming to your subnet, and operate above the Securtiy group ...
5lovak's user avatar
  • 472

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