Sometimes there's a need to automatically setup the hostname of an EC2 instance. This post shows how to do it from 'outside' of the instance itself, using Ansible. Let's assume here that the instance already has a tag Name, that will be used as…
This post shows how to set up various VPC-related resources using CloudFormation to enable IPv6 for them. Components Diagram below shows all the components described in this post. VPC IPv6 requires one additional resource - AWS::EC2::VPCCidrBlock to request an /56 block of addresses from AWS. rVPC: Type: "…
Sometimes, particularly when building new containers it would be good to have a look at the filesystem inside the container after it stopped or crashed, perhaps to have a look at the config files (if they got generated on the fly) or logs (if for some reason the processes there…
Docker directory ( /var/lib/docker on Linux) tends to grow very big with time. There are two main reasons for it: 1. Container logs 2. Old images Clearing container logs By default the container logs are written to /var/lib/docker/CONTAINER_ID/CONTAINER_ID-json.log. In order to trim…
There are many ways of building multi-process Docker container (by multi-process I mean the ones where there are multiple processes running simultaneously inside the container). Over time I found supervisord to be the easiest one to use to achieve good and reliable outcomes. This post describes the setup I use.…
It's been over 20 years since IPv6 was first defined, but many applications and systems (Docker included) shy away from actively using it. Running Docker with IPv6 is not complicated, but requires certain preparations and a slightly deeper understanding of Docker networking. The main difference between running on…
Docker docs (https://docs.docker.com/config/containers/multi-service_container/) aren't as categoric as they once used to be when it comes to building multi-process containers, but doing so comes at a cost of additional complexity and potentially decreased reliability. Single process containers Let's start with…