Python

How to setup Flask and Apache on an Ubuntu VM in DigitalOcean with a Custom Domain

In this video I show how setup Flask and Apache on an Ubuntu VM in Digital Ocean with a custom domain. This was made after someone in the comments on my other DigitalOcean video requested it. If there is something else anyone would like to see, please just let me know I am happy to provide these walk through’s.

Note: I hit a number of challenges with DNS in this one, I think it’s fun to watch me struggle. Enjoy!

How To: Create An AWS Lambda Function To Backup/Snapshot Your EBS Volumes

AWS Lambda functions are a great way to run some code on a trigger/schedule without needing a whole server dedicated to it. They can be cost effective, but be careful depending on how long they run, and the number of executions per hour, they can be quite costly as well.

For my use case, I wanted to create snapshot backups of EBS volumes for a Mongo Database every day. I originally implemented this using only CloudWatch, which is a monitoring service, but because it’s focused on scheduling, AWS also uses it for other things that require scheduling/cron like features. Unfortunately, the CloudWatch implementation of snapshot backups was very limited. I could not ‘tag’ the backups, which was certainly something I needed for easy finding and cleanups later (past a retention period).

Anyway, there were a couple pitfalls I ran into when creating this function.

Pitfalls

  1. Make sure you security group allows you to communicate to the Internet for any AWS API’s you need to talk to.
  2. Make sure your time-out is set to 1 minute or greater depending on your use case. The default is seconds, and is likely not high enough.
  3. “The Lambda function execution role must have permissions to create, describe and delete ENIs. AWS Lambda provides a permissions policy, AWSLambdaVPCAccessExecutionRole, with permissions for the necessary EC2 actions (ec2:CreateNetworkInterface, ec2:DescribeNetworkInterfaces, and ec2:DeleteNetworkInterface) that you can use when creating a role”
    1. Personally, I did inline permissions and included the specific actions.
  4. Upload your zip file and make sure your handler section is configured with the exact file_name.method_in_your_code_for_the_handler
  5. Also this one is more of an FYI, Lambda Function have a maximum TTL of 5 minutes ( 300 seconds).

I think that was it, after that everything worked fine. To finish this short article off, screenshots and the code!

Screenshots

 

 

And finally the code…

Function Code

And here is an additional function to add for cleanup

The end, happy server-lessing (ha !)

 

How to use Boto to Audit your AWS EC2 instance security groups

Boto is a Software Development Kit for accessing the AWS API’s using Python.

https://github.com/boto/boto3

Recently, I needed to determine how many of my EC2 instances were spawned in a public subnet, that also had security groups with wide open access on any port via any protocol to the instances. Because I have an IGW (Internet Gateway) in my VPC’s and properly setup routing tables, instances launched in the public subnets with wide open security groups (allowing ingress traffic from any source) is a really bad thing πŸ™‚

Here is the code I wrote to identify these naughty instances. It will require slight modifications in your own environment, to match your public subnet IP Ranges, EC2 Tags, and Account names.

To run this you also need to setup your .aws/config and .aws/credentials file.

http://docs.aws.amazon.com/cli/latest/userguide/cli-chap-getting-started.html#cli-config-files

Email me tuxninja [at] tuxlabs.com if you have any issues.
Boto is awesome πŸ™‚ Note so is the AWS CLI, but requires some shell scripting as opposed to Python to do cool stuff.

The github for this code hereΒ https://github.com/jasonriedel/AWS/blob/master/sg-audit.py

Enjoy !

Fun with Python, Tabular & AWS IP ranges

I have been spending a lot of time designing a Hybrid Cloud that consists of Openstack and public cloud platforms. In particular I have been spending a lot of time designing theΒ AWS portion of the Hybrid Cloud Platform. Today I found myself continually needing to look up AWS public address space and then parsing out regions & services. Then I remembered something a mentor of mine told me…

if you are going to do something more than once, there is probably value in automating it.

I love writing command line tools and thus a short Python script was born. Since I rarely share Python code, even though I didn’t spend a lot time on this, and I certainly didn’t optimize it for DRY etc. I am sharing it anyway for others to use, enjoy and hack on,

but mainly to learn, which is…The entire purpose of the Tuxlabs site

I should mention I have strong views about when to use Python vs. Go a language I find myself writing in more and more and this tool falls under my rules for things that I should write in Go. So later as a follow up I will likely re-code this in Go and post the code for review & learning. For now here’s the Python code, enjoy !

Listing all IP Ranges

Filtering

The code