Andrej Golis

My Watch Died Mid-Hike: Merging Two FIT Files with Python

Thu, 02 Jul 2026 14:05:00 +0200

Four and a half hours into a long hike my watch ran out of battery, so the descent got recorded with the Strava app on my phone. Strava cannot merge two activities into one, and the web tools that can want my GPS data uploaded to somebody else’s server. FIT is a documented binary format with a usable Python parser, so I stitched the two recordings together myself.

Two files, two very different recorders

Both devices export FIT. The parser is fit-tool:

Upgrading OKD 4.15 to 4.21 in Production: A Field Log

Thu, 25 Jun 2026 09:47:00 +0200

Six years ago I wrote about installing OKD 4.4 on AWS. This is the sequel nobody plans for: a production OKD cluster on AWS that had been sitting on 4.15 for well over a year, brought up to 4.21 in five upgrade windows over one weekend, including the cross-OS migration from Fedora CoreOS to CentOS Stream CoreOS. Every hop had at least one surprise, and almost none of them are documented in one place.

Rook-Ceph on Bare Metal: MTU Tuning and Proving Your 10G Network Is Actually 10G

Tue, 07 Apr 2026 10:18:00 +0200

I recently built a dedicated three-node Ceph cluster with Rook on bare metal to serve block, file and object storage to a small fleet of Kubernetes clusters. The Rook YAML turned out to be the easy part. The part that decides whether the cluster performs is the network underneath it, so this build went benchmark-first: prove the 10G network is actually delivering 10G before a single OSD exists, then benchmark Ceph against that baseline.

Red Hat Satellite Content Lifecycle as Code

Tue, 19 Dec 2023 09:38:00 +0100

Every Satellite I have inherited was managed by clicking through the UI, and nobody could say why a content view contained what it contained. For a recent multi-environment RHEL estate I put the whole content lifecycle - products, repositories, GPG keys, content views, activation keys, publish and promote - into a git repo driven by the redhat.satellite Ansible collection. These are the patterns that worked and the traps that cost me an afternoon each.

Surviving Leapp: Automating RHEL 7 to 8 Migrations at Scale with Ansible

Thu, 10 Aug 2023 11:23:00 +0200

Running Leapp against one server is a tutorial. Running it against a large enterprise estate is a campaign, and the failure modes are completely different. These are the traps I hit while automating RHEL 7 to 8 in-place upgrades with Ansible over the last few months, and the playbook patterns that fixed them.

The moving parts

Each migration wave runs through the same pipeline, driven from Ansible Automation Platform:

pre_upgrade.yml - patch to latest RHEL 7, install Leapp, preseed answers, re-register the host against the upgrade content view
rear_backup.yml - install ReaR, prepare local disk space, take a full backup to a remote backup server
leapp upgrade and reboot
post_upgrade.yml - cleanup, re-register against RHEL 8 content, application-specific fixes

Hosts come in as a simple list and get expanded into an in-memory inventory, so a wave is just a vars file:

Installation of Syndesis on OKD 4.4

Wed, 19 Aug 2020 13:11:01 +0200

The installation of Syndesis on OKD/OpenShift is pretty straightforward.

Clone the repository:

$ git clone https://github.com/syndesisio/syndesis.git

Add syndesis bin tools to your PATH:

$ export PATH=${PATH}:$(pwd)/syndesis/tools/bin

Source shell completion, e.g. zsh or bash - replace accordingly:

$ source <(syndesis completion zsh)

Make sure you are logged in to the cluster.

Install CRDs clusterwide. You have to run this option once as cluster admin.

$ syndesis install --setup

Install the latest version of Syndesis in syndesis project. If the project exists, it will be re-created.

OKD 4.4 Custom Letsencrypt certificate

Mon, 15 Jun 2020 13:24:56 +0200

Credits: https://www.openshift.com/blog/requesting-and-installing-lets-encrypt-certificates-for-openshift-4

Prerequisites

Create AWS credentials as described in the previous article. Replace the values accordingly.

$ cat << EOF > aws.credentials
#!/bin/bash
export AWS_ACCESS_KEY_ID=REPLACE_AWSACCESSKEYID
export AWS_SECRET_ACCESS_KEY=REPLACE_AWSSECRETACCESSKEY
EOF

$ source aws.credentials
$

Make sure you are logged in to the cluster.

$ export KUBECONFIG=${PWD}/config/auth/kubeconfig
$ oc get node
NAME STATUS ROLES AGE VERSION
ip-10-0-128-29.eu-west-1.compute.internal Ready worker 68m v1.17.1
ip-10-0-140-213.eu-west-1.compute.internal Ready master 78m v1.17.1
ip-10-0-149-203.eu-west-1.compute.internal Ready master 77m v1.17.1
ip-10-0-150-180.eu-west-1.compute.internal Ready worker 68m v1.17.1
ip-10-0-169-24.eu-west-1.compute.internal Ready worker 68m v1.17.1
ip-10-0-175-121.eu-west-1.compute.internal Ready master 78m v1.17.1
$ oc whoami
system:admin
$

Clone acme.sh github repo.

OKD 4.4 beta5 installation on AWS

Mon, 15 Jun 2020 10:43:34 +0200

This post briefly describes the installation process of OKD 4.4-beta5 on AWS.

Prerequisites

AWS account has to be configured before the actual installation. The process is described in the official docs.

Once the IAM user is configured, create aws.credentials file and source it. Replace the values accordingly.

$ cat << EOF > aws.credentials
#!/bin/bash
export AWS_ACCESS_KEY_ID=REPLACE_AWSACCESSKEYID
export AWS_SECRET_ACCESS_KEY=REPLACE_AWSSECRETACCESSKEY
EOF

$ source aws.credentials
$

Download and extract the installer and cli

I am using mac, that is the reason for downloading mac binaries. Make sure to download correct tarballs for your OS.

OpenShift node disk space disappeared

Wed, 04 Sep 2019 15:25:51 +0200

Filesystem usage displayed by df does not match total usage displayed by du, e.g. 24 GB vs. ~4.7G:

[root@server1 /]# df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/rhel_server1-root 27G 24G 2.7G 90% /

[root@server1 /]# du -shx * --exclude proc --exclude sys | sort -h
0 bin
0 dev
0 home
0 lib
0 lib64
0 media
0 mnt
0 sbin
0 secrets
0 srv
4.0K tmp
13M opt
50M etc
182M root
187M boot
429M run
1.5G var
2.3G usr

Display human readable size from lsof output:

Ansible and Hashicorp Better Together

Wed, 04 Sep 2019 08:54:15 +0200

How to call Ansible during provisioning by Terraform:

https://www.youtube.com/watch?v=-gKTeT3BgHE

Transcript:

https://www.hashicorp.com/resources/ansible-terraform-better-together

Blue Green Deployment across K8S version using PX-Motion | Portworx

Tue, 03 Sep 2019 09:44:05 +0200

Exploring PX-Motion: How to perform Blue-Green deployments for stateful workloads across Kubernetes versions

Demo of blue-green deployment across two different k8s clusters using Portworx’s PX-Motion:

https://portworx.com/perform-blue-green-deployments-stateful-workloads-across-kubernetes-versions/

TED Talks

Wed, 28 Aug 2019 16:51:31 +0200

Some interesting TED talks:

Thorium can give humanity clean, pollution free energy | Kirk Sorensen | TEDxColoradoSprings
https://www.youtube.com/watch?v=kybenSq0KPo

How to green the world’s deserts and reverse climate change | Allan Savory
https://www.youtube.com/watch?v=vpTHi7O66pI

Restoring the ancient Caledonian Forest Alan Watson Featherstone TEDxFindhorn
https://www.youtube.com/watch?v=nAGHUkby2Is