If you work from place to place, such as from one coffee shop to another, and you need access to your Amazon EC2 instances, but you don’t want to allow traffics from all IP addresses. You can use the EC2 Security Groups to allow the IP addresses from those locations. But once you move on to a different location, you want to delete the IP address from the previous location. The process to do these manually and over and over again quickly becomes cumbersome. Here is a command line method that quickly removes all other locations and allows only the traffic from your current location.

The steps are:

1. Revoke all existing sources to a particular port
2. Grant access to the port only from the current IP address

Assume the following:

• Profile: default
• Security group: mygroup
• Protocol: tcp
• Port: 22

First, revoke access to the port from all IP addresses:

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$ aws ec2 describe-security-groups \
    --profile default \
    --group-names mygroup \
    --query 'SecurityGroups[0].IpPermissions[?ToPort==`22`].IpRanges[].CidrIp' | \
  jq .[] | \
  xargs -n 1 aws ec2 revoke-security-group-ingress \
    --profile default \
    --group-name mygroup \
    --protocol tcp \
    --port 22 \
    --cidr

The aws ec2 describe-security-groups command before the first pipe returns JSON formatted data, filtered via JMESPath query, which is supported by AWS CLI, for example:

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[
  "XXX.XXX.XXX.XXX/32",
  "XXX.XXX.XXX.XXX/32"
]

jq command simply converts an array of JSON to line by line strings, which xarg takes in, loops through and deletes one IP address at a time.

After this step, all IP addresses originally allowed are all revoked. Next step is to grant access to the port from a single IP address:

1. What is Vagrant?
2. What are the main features?
3. Why do they build it?
4. How would it benefit me?
5. Where does this fit into the stack?

What is Vagrant?

Vagrant is a configuration management tool for creating, configuring, and managing complete development environments in virtual machine.

What are the main features?

Development environment version control

Configuration for setting up development environment is in code (Vagrantfile), so the development environment can be version controlled.

Consistent but distributed development environments

Consistent development environment, build one development environment, and distribute to the rest of the team. Create identical development environment for everyone on the team.

Distributed development environment, but linked by source control. “I like to think of Vagrant as the Git of development clouds. Centralized development and test environments create bottlenecks. Vagrant lets developers work at their own pace and in their own environment, while keeping all the environment synchronized with each other.” (By Jeff Sussna) [1].

Disposable computing resource

“Vagrant lowers development environment setup time, increases development/production parity, and brings the idea of disposable compute resources down to the desktop.” [1]

“At the end of the day, Vagrant can suspend, halt, or destroy the development environment, keeping the overall system clean. Never again can developers forget to shut down a stray server process and waste precious compute resources.” [1]

Simple development environment setup

Forget about README or INSTALL instructions, type vagrant up and you are good to go.

“Say goodbye to ‘works on my machine’ bugs.” [2] For designers, “no more bothering other developers to help you fix your environment so you can test designs. Just check out the code, vagrant up, and start designing.” [2]