IaaS – RedThunder.Blog

Hashicorp’s cidrsubnet function

A while back I witnessed a Terraform presentation where a subnet’s IPv4 CIDR block was constructed from a parent VCN by invoking a Hashicorp function called cidrsubnet. This function is very useful because it can save time when you have multiple VCNs in your Terraform code. And it is universal, it can be used when there are several concurrent Terraform providers in the same code.

The function’s format is like this: cidrsubnet(prefix, newbits, netnum).

The prefix field is for the VCN CIDR. You can enter a variable in the prefix field. For example cidrsubnet(var.vcn_cidr, 8,1). Let’s say that the VCN CIDR is 10.0.0.0/16, then the value of var.vcn_cidr is 10.0.0.0/16. So, the function looks like this: cidersubnet(“10.0.0.0/16”,8,1).

The newbits value is the number of digits that you will be adding to the actual CIDR value. 16 + 8 = 24, so the subnet will be a /24 subnet.

The netnum value is for completing the actual subnet, and it depicts the “raw” decimal number of the binary portion of the subnet side of the CIDR, in this case is the third octet. The result for the subnet is 10.0.1.0/24.

This example illustrates it better:

cidrsubnet(“10.1.2.0/24”, 4, 15). 24+4 = 28, so the subnet will be a x.x.x.x/28 subnet.

The value in the netnum field will help us identify which of the 16 possible /28 subnets we’re creating. On a /28 subnet, in the fourth octet, the four left bits are the subnetwork bits. Convert 15 (the netnum value) to binary and you will get 1111. Place it on the subnetwork side of the fourth octet and you will get 1111|0000. The decimal value of the whole octet is 240, therefore the subnet is 10.1.2.240/28.

This is optimal, isn’t it?

#BuildWithAI 2021 Team Tribute

#BuildWithAI Hackathon 2021 comes at a different point in time. Last year it was a little of an unknown. This is the second year that this event has been run and there was more of an understanding about what to expect and who might be participating.

As like last time, it is a privilege to write this article as there has been significant effort to get to these outcomes. If all I do is to highlight those that have been generous with their time, knowledge and willingness to participate, then it is a service that I will do every time. Here is a recount of some of the teams that participated at the #BuildWithAI Hackathon 2021 (and who were the winners).

This is a tribute.

The one ask that I do have for those is to connect. Connect with the problem; connect with the team and make this tribute more than an article but a way to #BuildWithAI.

#BuildWithAI 2021 – Another Step

Last weekend (from Friday 29th Oct to Tuesday 2nd Nov), was the #BuildWithAI Hackathon 2021 where participants, mentors, sponsors and organisers gathered together to solve real world challenges with AI. This event does not standalone. In a world full of change, this (from my perspective) started last year in the #BuildWithAI Hackathon 2020 and continued to build.

This article is about the event but the event itself is just “Another Step”.

#DaysOfArm (15 of X)

This is my 15th #DaysOfArm article that tracks some of the experiences that I’ve had so far. It’s been a little while since I’ve worked on this series however saying that … much of what I’ve been doing didn’t seem different from any other type of environment.

And just to recap from the first post (here) on June 12 2021.

It’s been just over 2 weeks since the launch of Ampere Arm deployed in Oracle Cloud Infrastructure (OCI). Check this article out to learn more (here). And it’s been about one week since I started looking into the new architecture and deployment, since I started provisioning the VM.Standard.A1.Flex Compute Shape on OCI and since I started migrating a specific application that has many different variations to it to test it all out.

This is my next learning where I looked into Let’s Encrypt to create a set of free certificates for Oracle Cloud Infrastructure A1.Flex VM Instances.

OCI Arcade Now Has A CRM

As each project comes along, there’s something new to add to the OCI Arcade. It started off with the game and Autonomous Database. And then grew into including Kafka, Docker Swarm, Serverless with the FN Project, Terraform, OAuth, Ansible, In-Memory Data Grid with Coherence-CE and more recently with Arm. This time round we’ve adding in a Customer Relationship Management (CRM) solution. Why? Up to now, users has been a simple identifier to denote the scores and the events in the game. Nothing more; nothing less. By adding in a CRM into the mix, we’ve opening up the understanding about our contacts and customers providing a richer experience for those coming to the arcade. And ultimately, from a space where we are build, experiment and try something out – adding user profiles opens up endless possibilities. Check out the rest of this about how it’s changed and some of the things we needed to do to make this happen.

Bastion Access For Minecraft

In the previous post, I did some work in managing Security Lists to protect the Minecraft Server. To read about that, head (here). Another method of connecting to the Minecraft Server is through a Bastion Host. As part of Oracle Cloud Infrastructure, it is free to create a session through the Bastion Service (service limits do apply). Here’s a brief encounter of getting this up and going.

#DaysOfArm (14 of X)

This is my 14th #DaysOfArm article that tracks some of the experiences that I’ve had so far. And just to recap from the first post (here) on June 12 2021.

This is my next learning where I’ve deployed successfully openrouteservice – an open-source routing / direction API all deployed on an 4 OCPU with 24 GB of RAM in an Always Free Tier tenancy.

#DaysOfArm (13 of X)

This is my 13th #DaysOfArm article that tracks some of the experiences that I’ve had so far. And just to recap from the first post (here) on June 12 2021.

This is my next learning is another retrospective with the OCI Arcade deployment the full stack is now being deployed on 1 OCPU with 6 GB of RAM in an Always Free Tier tenancy.

#DaysOfArm (12 of X)

This is my 12th #DaysOfArm article that tracks some of the experiences that I’ve had so far. And just to recap from the first post (here) on June 12 2021.

This is my next learning where I’ve deployed successfully Pelias – an open-source geocode API all deployed on an 4 OCPU with 24 GB of RAM in an Always Free Tier tenancy.

(Update – 11th Oct 2021 – there’s been some changes made as this is a working document … as some of the packages have changed as well as additional fixes to make it easier …)

(Update – 28th Dec 2022 – I’ve refreshed the instructions for this blog post to match what is happening with Pelias as there’s been some cool changes to support arm64).

#DaysOfArm (11 of X)

This is my 11th #DaysOfArm article that tracks some of the experiences that I’ve had so far. And just to recap from the first post (here) on June 12 2021.

This is my next learning which I focuses on Arm’s availability in our cloud.