Module · DevOps Engineer

Observability

Metrics, logs and alerts — knowing what your systems are doing.

5 topics6 interactive tasks

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TOPIC 01

Metrics from Logs

Numbers come from somewhere — learn to extract them.

What you'll practice

Count HTTP 5xx Errors — practice · beginner

A command you'll meet

cat /var/log/app/access.log

Open any task below to get the full step-by-step walkthrough — every command is explained, and the lab validator checks what you actually built.

Hands-On Tasks in This Topic (1)

beginner

Practice Task

Count HTTP 5xx Errors

Every dashboard number starts as raw events. The app's access log is at /var/log/app/access.log — count the HTTP 500 responses and record the number your dashboard would show.

Environment: ubuntu:24.04Launch Lab ⚡

TOPIC 02

Log Triage

Extract the signal from the noise.

What you'll practice

Extract Errors for the Incident Report — practice · beginner

A command you'll meet

head /var/log/app/app-2026-09-27.log

Open any task below to get the full step-by-step walkthrough — every command is explained, and the lab validator checks what you actually built.

Hands-On Tasks in This Topic (1)

beginner

Practice Task

Extract Errors for the Incident Report

During an incident you hand the on-call engineer a filtered log, not a gigabyte file. Extract every ERROR line from yesterday's app log into a dedicated file.

Environment: ubuntu:24.04Launch Lab ⚡

TOPIC 03

Alerting

A rule that pages a human should be precious.

What you'll practice

Write a Prometheus Alert Rule — guided · intermediate

A command you'll meet

mkdir ~/alerts

Open any task below to get the full step-by-step walkthrough — every command is explained, and the lab validator checks what you actually built.

Hands-On Tasks in This Topic (1)

intermediate

Guided Task

Write a Prometheus Alert Rule

Alert rules are YAML files too. Write a Prometheus rule that fires when the error rate stays too high — and learn the two halves of every alert: expression and duration.

Environment: ubuntu:24.04Launch Lab ⚡

TOPIC 04

SLOs & Error Budgets

Reliability promises written as numbers you are allowed to spend.

What you'll practice

Write the SLO and Its Error Budget — challenge · intermediate

A command you'll meet

echo 'availability_target=99.9' > ~/slo/slo.txt

Open any task below to get the full step-by-step walkthrough — every command is explained, and the lab validator checks what you actually built.

Hands-On Tasks in This Topic (1)

intermediate

Challenge

Write the SLO and Its Error Budget

The product team promised customers 99.9% availability this quarter — a promise nobody can act on until it is written down as two numbers. Record the target in ~/slo/slo.txt and work out the error budget it implies into ~/slo/budget.txt.

Environment: ubuntu:24.04Launch Lab ⚡

TOPIC 05

Dashboards & Burn Rates

Put the right numbers on one screen, and alert on how fast the error budget is burning.

What you'll practice

Build a Dashboard Definition — practice · intermediate
Alert on Error Budget Burn — challenge · advanced

A command you'll meet

cat ~/dashboards/api.json

A dashboard is a product: someone has to use it at 3am. Open the task below for the full walkthrough.

Hands-On Tasks in This Topic (2)

intermediate

Practice Task

Build a Dashboard Definition

Dashboards are code - a JSON definition that can be reviewed and deployed. Build one for the API with a request-rate panel and an error-rate panel.

Environment: ubuntu:24.04Launch Lab ⚡

advanced

Challenge

Alert on Error Budget Burn

Paging on every error wastes attention. Burn-rate alerting pages when the error budget is being consumed far too fast - write the rule that does it.

Environment: ubuntu:24.04Launch Lab ⚡