Posts

Ansible vs PCI

If you need to comply with PCI
requirements
like:

Requirement 2: Maintain an inventory of system components in scope for PCI DSS
to support effective scoping practices.

You will find that using public-key authentication is sometimes
forbidden
as it’s almost impossible to ensure employees are rotating the keys, keeping the
private key safe and with a strong password.

Using Ansible without ssh key based authentication is painful if you need to
run a playbook against hundreds of servers, as you will need to insert your
password ad nauseam.

Docker: Configuration files

Things no one tells you about.

One of Docker’s killer features is the environment
parity, yet it feels like one little detail was left untold: how to handle
configuration files.

Unless you are using the same configuration between development, quality,
production, etc. you will end up with different endpoints, API keys, secret
tokens and feature switches for each environment.

Available Options

There are a couple of different ways to handle configuration in Docker. Below,
you will find a non-exhaustive list.

Collectd plugins made easy

Collectd is a Unix daemon that collects, transfers and stores performance
data of computers and network equipment. The acquired data is meant to help
system administrators maintain an overview over available resources to detect
existing or looming bottlenecks.

Collectd provides a long list of
plugins available
out-of-box. However, if you need to collect additional metrics, one of the
easiest ways to do so is using the exec
plugin.

In order to use the exec plugin, create an Collectd configuration file:

Chef Custom Resources

Lately I’ve been writing some Chef code. One of the best things about Chef
is custom resources:
https://docs.chef.io/custom_resources.html

Let’s see an example on how to create a Kafka topic
using Chef and how to make it
idempotent.

Before writing any Chef code it is important to understand how to manage a
topic (grouping of messages of a similar type).

From the Kafka install directory, first check if the topic already exists:

bin/kafka-topics.sh
    --zookeeper localhost:2181 \
    --describe \
    --topic <name>

If it doesn’t exist, create it: