Introduction Let's Encrypt and the ACME protocol enable getting free (as in beer) TLS/SSL certificates. The main use for Let's Encrypt is to enable HTTPS on web servers. Let's Encrypt TLS certificates expire pretty quickly, in 3 months, but the idea is that renewal is automated so that you don't ever really have to worry […]
The symptoms I recently received and email from Amazon Route53 asking me to verify the contact details for one of our registered DNS domains (replaced here with example.org). And sure enough, I saw wrong Route53 domain contact details in the email: These wrong Route53 domain contact details originate from whois data for the registered domain. […]
Causes for the Terraform AWS UnauthorizedOperation errors Terraform is an infrastructure as code tool you can use to configure Cloud resources in AWS. When using Terraform AWS provider you frequently run into various UnauthorizedOperation errors when creating, modifying or deleting resources. That happens unless you do what you should not do and let Terraform use […]
Introduction AWS recommends that you disable S3 bucket ACLs for all new buckets. To understand why some background information is needed. AWS S3 providers two ways to manage access to S3 buckets and objects: AWS combines IAM policies and ACLs to figure out the effective access control rules for objects in an S3 bucket. The […]
When you create a distribution, AWS creates several DNS A records with the same name (e.g. d25gma2ea3ckma.cloudfront.net) which point to IPs the distribution is using. Then, typically, you would define CNAME(s) pointing to that cloudfront.net address in your own DNS. Each Cloudfront distribution has a list of aliases, similar to Subject Alternative Names ("SAN") in […]
The aws_instance resource in Terraform can automatically create the default network interface for you. There are cases, however, when you notice that the default network interface is not enough anymore, and modifying it via the limited aws_instance parameters is not sufficient. In these cases you can convert the interface into an aws_network_interface resource, but the […]
In AWS EBS ("Elastic Block Storage") is the underlying technology that (virtual) hard disks of your instances (virtual machines) use. You can take snapshots of those virtual hard disks and use those snapshots to, for example: Debugging issues with unbootable virtual machines: attach and then mount the snapshot on another virtual machine and investigate what […]
This article assumes that the user backend for Keycloak is FreeIPA. Regardless of that the instructions will apply to any other setup with minor modifications. Here we use two different AWS accounts renamed to 123412341234 and 567856785678 to protect the personal information of the innocent. The Keycloak staging cluster on which this integration was done […]
AWS EC2 instances are subject to two types of status checks (AWS docs): System status check (issues with the underlying hardware/networking: "the AWS side") Instance status check (issues with the OS, e.g. OOM, file system corruption, broken networking, etc: "our side") The official AWS EC2 instance recovery documentation claims that automatically recovering from an EC2 […]
The Using tags in Puppet Bolt aws_inventory target_mapping showed how to use AWS "Name" tag as the target name for Puppet Bolt. Use of tags can be extended to creating Bolt target groups: All you need to do is add a "filter" section with one filter. The "name" parameter tells Bolt that the filter is […]
I recently checked the pricing model for Amazon Fargate to see if migrating a fair number of EC2 instance-based workloads to containers would save money. In theory this should have been the case, as a container has less "fat" compared to a full virtual machine. In this case the workload itself was perfectly suited for […]
We're migrating away from Ansible to Puppet Bolt and the fact that Ansible updates broke the old ec2.py inventory script expedited that process. While that inventory script was quite rudimentary, it was able to automatically add human-readable names to the EC2 instance names. So, for example, you could target a node using "server_example_org" if the […]
This blog post shows how to grant access to an AWS account for some external party. For simplicity we will call this external party a "contractor". If you want to do the same for Microsoft Azure look at this blog post instead. This method requires the contractor to have its own AWS account, but it […]
Sometimes Terraform stalls when trying to remove AWS EC2 security groups and Terraform does no give any hint as to what is wrong. The problem is caused by that security group being attached to an EC2 instance or network interface. Interestingly Terraform messes up the order of the AWS API calls even when it (attempts […]
We use Terraform for managing our Cloud infrastructure. Our customers typically use AWS and that's what we're most familiar with. Each public Cloud has its own terminology, so this page is a translation table between Terraform resource names in the AWS and Azure providers: AWS Azure aws_instance azurerm_linux_virtual_machine aws_network_interface azurerm_network_interface aws_security_group azurerm_network_security_group aws_security_group_rule azurerm_network_security_rule aws_vpc […]
