AJ's Blog

Getting Started with Excalidraw

If you’ve ever wished diagramming tools felt less like enterprise software and more like grabbing a marker and sketching on a whiteboard, you will like Excalidraw. It’s fast, intuitive, works offline, supports collaboration, and keeps things simple without getting in your way.

This post walks you through installation options and essential usage.

What Is Excalidraw?

Excalidraw is an open-source, zero-friction virtual whiteboard that produces hand-drawn-style diagrams. It’s used by engineers, product teams, DevOps, architects, and teachers.

Opencode and Ollama

Running AI-powered coding assistants locally doesn’t have to break the bank or compromise your privacy. With OpenCode and Ollama, you can create a local development environment that compares to commercial tools like Claude Code and Gemini CLI. All will run on your network instead of some cloud platform.

In this post, we’ll walk through everything you need to know to get OpenCode working seamlessly with Ollama’s local models.

What You’ll Need

Before we dive in, make sure you have:

Capture Nanosecond Metrics with Telegraf + InfluxDB v1

Telegraf is an open-source metrics collection agent that gathers system and application data, while InfluxDB is a time-series database built for storing these metrics. Telegraf can write directly into InfluxDB with nanosecond precision giving you finer granularity than Prometheus, which stores measurements in milliseconds. This guide shows how to collect metrics from your host and applications, store them in InfluxDB 1.x, and maintain a minimal containerized setup. I have used all of these tools at work and in my homelab. If you are not familiar with Telegraf, check out a previous post where I set it up along with Prometheus.

Monitor Your apps and systems with Telegraf + Prometheus

Telegraf makes it easy to collect many types of metrics and you only configure what you need. Prometheus makes metric storage effortless. Together they form a monitoring stack you can run anywhere Docker works.

By the end of this post you’ll have:

• Telegraf exporting metrics at /metrics
• Prometheus scraping those metrics every 10 seconds
• A foundation you can plug into Grafana for dashboards

Prometheus can scrape metrics for you directly but sometimes applications are written to emit metrics when an event occurs and telegraf can aggregate those metrics for you. If your application has tens or hundreds of servers all emitting metrics, telegraf can help you aggregate those metrics before they are stored in prometheus (or another system to store time-series data). Otherwise you would need prometheus to scrape hundreds of different endpoints or only collect a sample of metrics from something like a load balancer endpoint.

Store metrics with Grafana Mimir

Grafana Mimir is a powerful, horizontally scalable, multi-tenant long-term store for Prometheus metrics. In this post, we’ll spin up a lean, monolithic Mimir stack with Docker Compose. We’ll use local filesystem storage for quick experiments, plus Prometheus for scraping and Grafana Alloy for collecting and forwarding telemetry. I have used this project to store metrics from over 6 different Kubernetes Clusters in one central data repository (Mimir in this case).

Monitor Your Linux System with the Elastic Stack

With the Elastic Stack (formerly known as ELK Stack) and Docker Compose, you can set up a powerful monitoring solution that is also equipped to scale as a backend document database for modern software applications. I am giving it another go in 2025 since I use Elastic in my current job. If you have never heard of Elasticsearch (which is fair if you do not work in software development), check out a previous post for a brief overview of how to get started.