https://opscanopy.com/blog/ DevOps articles, guides, and tutorials from the OpsCanopy team — delivered right to your reader. en Sun, 12 Jul 2026 00:00:00 GMT https://opscanopy.com/blog/learn-devops-in-90-days/ https://opscanopy.com/blog/learn-devops-in-90-days/ Why we built Mission: 90 Days DevOps — a free day-by-day path from Linux to Kubernetes with playable incident missions. The full plan, the design decisions, and the honest tradeoffs. Sun, 12 Jul 2026 00:00:00 GMT devops career learning https://opscanopy.com/blog/debug-alertmanager-routing/ https://opscanopy.com/blog/debug-alertmanager-routing/ Alerts going to the wrong receiver, or no receiver at all? Debug Alertmanager routing — first-match-wins, missing continue, matcher regex and catch-all defaults. Thu, 18 Jun 2026 00:00:00 GMT alertmanager observability alerting https://opscanopy.com/blog/how-alertmanager-routing-works/ https://opscanopy.com/blog/how-alertmanager-routing-works/ A clear mental model for Alertmanager routing — the route tree, matchers, the continue flag, grouping and receiver inheritance — so you know exactly where an alert goes. Wed, 17 Jun 2026 00:00:00 GMT alertmanager observability alerting https://opscanopy.com/blog/debug-prometheus-relabeling/ https://opscanopy.com/blog/debug-prometheus-relabeling/ A target vanished or a label disappeared after relabeling. Debug Prometheus relabel_configs vs metric_relabel_configs, regex anchoring and keep/drop logic. Tue, 16 Jun 2026 00:00:00 GMT prometheus observability relabeling https://opscanopy.com/blog/github-actions-if-condition-always-true/ https://opscanopy.com/blog/github-actions-if-condition-always-true/ Your GitHub Actions if condition always runs true? It's the literal-text footgun: any text outside ${{ }} coerces to a truthy string. Here's the cause and the fix. Sun, 14 Jun 2026 00:00:00 GMT github-actions ci-cd https://opscanopy.com/blog/github-actions-workflow-not-triggering-filters/ https://opscanopy.com/blog/github-actions-workflow-not-triggering-filters/ Why your GitHub Actions workflow didn't trigger: branch name mismatch, the AND-semantics of branches + paths filters, the ** glob requirement, paths-ignore on pull_request, and the fixes. Sun, 14 Jun 2026 00:00:00 GMT github-actions ci-cd debugging https://opscanopy.com/blog/prometheus-relabel-configs-explained/ https://opscanopy.com/blog/prometheus-relabel-configs-explained/ Understand Prometheus relabel_configs end to end — source_labels, regex, replacement and every action (replace, keep, drop, labelmap, hashmod) — with copy-paste recipes. Sat, 13 Jun 2026 00:00:00 GMT prometheus observability relabeling https://opscanopy.com/blog/common-gitlab-ci-mistakes/ https://opscanopy.com/blog/common-gitlab-ci-mistakes/ The .gitlab-ci.yml mistakes that turn pipelines red: undefined stages, jobs without scripts, broken needs and rules, anchor misuse — each with a fix you can copy. Fri, 12 Jun 2026 00:00:00 GMT gitlab-ci ci-cd yaml https://opscanopy.com/blog/validate-gitlab-ci-yml/ https://opscanopy.com/blog/validate-gitlab-ci-yml/ Stop pushing broken pipelines. Validate your .gitlab-ci.yml for YAML and structural errors in your browser — before the commit, not after the red pipeline. Thu, 11 Jun 2026 00:00:00 GMT gitlab-ci ci-cd yaml https://opscanopy.com/blog/docker-run-vs-compose/ https://opscanopy.com/blog/docker-run-vs-compose/ When to use docker run, when to switch to Docker Compose, and how to convert between them in both directions — with volumes, networks and reproducibility handled right. Wed, 10 Jun 2026 00:00:00 GMT docker docker-compose containers https://opscanopy.com/blog/convert-docker-run-to-compose/ https://opscanopy.com/blog/convert-docker-run-to-compose/ Convert any docker run command to a docker-compose.yml service, flag by flag — ports, volumes, environment, restart and more. A practical, copy-paste guide. Tue, 09 Jun 2026 00:00:00 GMT docker docker-compose containers https://opscanopy.com/blog/reading-promql/ https://opscanopy.com/blog/reading-promql/ A PromQL query is read from the inside out, not left to right. Learn the four layers — selectors, ranges, functions and aggregations — so you can decode any Prometheus expression at a glance. Mon, 08 Jun 2026 00:00:00 GMT promql prometheus observability https://opscanopy.com/blog/logql-vs-promql/ https://opscanopy.com/blog/logql-vs-promql/ LogQL borrows PromQL’s shape but starts from log lines, not metrics. Here is how the two query languages line up, where they translate cleanly, and where they simply don’t. Fri, 05 Jun 2026 00:00:00 GMT logql promql observability https://opscanopy.com/blog/env-example-drift/ https://opscanopy.com/blog/env-example-drift/ Your .env.example is documentation that silently rots. Here is why env drift breaks onboarding and deploys, how to detect missing and unused keys, and how to keep the example file honest. Tue, 02 Jun 2026 00:00:00 GMT configuration developer-experience twelve-factor https://opscanopy.com/blog/regex-for-log-lines/ https://opscanopy.com/blog/regex-for-log-lines/ A practical guide to building regexes that parse log lines reliably — anchoring, capture groups, escaping, greediness and the failure modes that bite you in production. Wed, 27 May 2026 00:00:00 GMT regex logs parsing https://opscanopy.com/blog/cron-to-systemd-timers/ https://opscanopy.com/blog/cron-to-systemd-timers/ A practical guide to converting crontab entries into systemd .timer and .service units — OnCalendar syntax, logging, randomized delays, catch-up runs, and the gotchas that bite during migration. Wed, 20 May 2026 00:00:00 GMT systemd cron linux https://opscanopy.com/blog/cron-expressions-explained/ https://opscanopy.com/blog/cron-expressions-explained/ A practical, field-by-field guide to reading cron expressions — the five time fields, ranges, steps, lists and @macros — plus the gotchas that make schedules fire when you least expect. Wed, 13 May 2026 00:00:00 GMT cron scheduling devops https://opscanopy.com/blog/github-actions-security-misconfigurations/ https://opscanopy.com/blog/github-actions-security-misconfigurations/ YAML validators catch syntax, not exposure. Here are the five high-impact GitHub Actions misconfigurations — pull_request_target, script injection, unpinned actions, broad GITHUB_TOKEN scopes, and curl|bash — with the bad pattern and the fix for each. Wed, 06 May 2026 00:00:00 GMT github-actions security ci-cd https://opscanopy.com/blog/unifying-cve-ignore-files/ https://opscanopy.com/blog/unifying-cve-ignore-files/ A single triaged CVE suppression has to be re-encoded in .trivyignore, .grype.yaml, .snyk and osv-scanner.toml — each with a different shape. Here is the same suppression in all four formats, what maps cleanly, and what is lossy. Wed, 29 Apr 2026 00:00:00 GMT security vulnerability-management devops https://opscanopy.com/blog/unit-testing-loki-alert-rules/ https://opscanopy.com/blog/unit-testing-loki-alert-rules/ Prometheus has promtool test rules. Loki has nothing equivalent. Here is why testing LogQL alert rules matters, what a Loki rule unit test should look like, and how to close the gap today. Wed, 15 Apr 2026 00:00:00 GMT loki observability testing