194 lines
8.2 KiB
Markdown
194 lines
8.2 KiB
Markdown
# Operations runbook
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This runbook describes the commands that are implemented and verified in this
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repository. It does not claim a production recovery point objective, recovery
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time objective, retention period, storage capacity, or high-availability model;
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those values require product policy and measurements from the eventual
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production environment.
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## Compose database backup
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Create a PostgreSQL 18 custom-format archive, validate its table of contents,
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and write a SHA-256 manifest:
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```bash
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./scripts/backup-compose.sh
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```
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The default destination is the ignored `output/backups/` directory. An explicit
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new destination may be supplied as the only argument. The command refuses to
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overwrite either an archive or its checksum manifest and writes through
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temporary files before publishing the final pair. Files and newly created
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directories are restricted by `umask 077`.
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The archive covers the configured application database. PostgreSQL cluster
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globals such as roles and tablespaces are not part of `pg_dump`; deployment
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credentials and database roles must be provisioned separately from secrets.
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Local backup files on the same workstation are not an off-site backup.
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## Isolated restore drill
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Run a real restore into a uniquely named temporary database:
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```bash
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./scripts/restore-drill-compose.sh output/backups/compose-YYYYMMDD-HHMMSS.dump
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```
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The drill:
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1. validates the SHA-256 manifest;
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2. validates the archive table of contents;
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3. creates a pristine database from `template0`;
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4. restores with `pg_restore --exit-on-error`;
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5. reads every restored public application table and checks the PostGIS
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library;
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6. runs the current immutable release's migrations and migration-readiness check
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against only the temporary database;
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7. drops only the temporary drill database and verifies that it is gone.
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A trap also attempts to drop the exact temporary database if a check fails.
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The source application database is never passed to `pg_restore`, `dropdb`, a
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clean operation, or the drill migration runner. The drill intentionally does
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not compare an older backup's row counts to the live source, because concurrent
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legitimate writes or a historical archive would make that comparison invalid.
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## Service checks
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```bash
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docker compose ps
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curl --fail http://localhost:4010/healthz/live
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curl --fail http://localhost:4010/healthz/ready
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./scripts/verify-realtime-cluster.sh compose
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```
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`live` verifies that the web process can serve HTTP. `ready` additionally runs
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`SELECT 1` through the configured Ecto repository. The cluster probe subscribes
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on one connected BEAM node and broadcasts from another.
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Health checks do not replace alerting, database backups, restore drills, or
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application-level synthetic checks.
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## Local failure and rolling-replacement drills
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The isolated load project can exercise process crashes, sequential container
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replacement, and a real Oban retry without touching the normal Compose project:
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```bash
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./scripts/load-stack-up.sh
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./scripts/load-resilience-run.sh local-resilience
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```
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The resilience script refuses `LOAD_PROJECT=who_need_help` and verifies the
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Compose project/service labels of every container before stopping it. It:
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1. continuously calls readiness through the isolated Traefik route;
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2. terminates the BEAM process in one web and one worker container and requires
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Docker's observed restart count to increase;
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3. removes and replaces each web and worker replica one at a time;
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4. waits for every configured BEAM node, then runs the cross-node PubSub probe;
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5. enqueues a side-effect-free local worker that fails its first Oban attempt
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and succeeds on its second;
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6. removes that exact Oban row and requires no fixture domain rows to remain.
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Traefik's retry middleware is attached to the HTTP and local TLS routers. Its
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attempt count is an environment input. Traefik retries transport failures and,
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with the checked configuration, does not opt in to retrying non-idempotent
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requests. This reduces a stale-backend window; it is not a claim of production
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availability.
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For the project-owned kind cluster, run:
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```bash
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./scripts/kind-rolling-verify.sh local-kind-rollout
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```
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That script requires both the kind ownership marker and the control-plane
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cluster label before invoking `rollout restart`. It changes only the web and
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worker Deployment pod templates. It snapshots application-table counts before
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and after, continuously probes the observed Docker mapping for the chart's
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NodePort, requires all four old pod UIDs to disappear, waits for the exact BEAM
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peer count, and verifies cross-node PubSub. PostGIS, its hostPath, the
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Kubernetes Secret, and the namespace are not recreated.
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The rollout timeout, probe interval/timeout/retry count, and cluster-join
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timeout are experiment inputs. They are not production SLOs or resource
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requirements.
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## Protected Prometheus metrics
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The web role exposes Prometheus text format at `/metrics`. It requires the
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independent `METRICS_TOKEN` deployment secret:
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```bash
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curl --fail \
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--header "Authorization: Bearer $METRICS_TOKEN" \
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http://localhost:4010/metrics
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```
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The endpoint returns `401` without the exact token, disables response caching,
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and does not put the credential in a URL. The reporter exports cumulative HTTP
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request and duration, router exception, database query and duration, WebSocket
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connection, VM memory, and scheduler run-queue metrics. Cumulative durations are
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integer microseconds because the selected reporter's sum accumulator is
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integer-based; divide by `1_000_000` in PromQL when seconds are required.
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Definitions intentionally have no request path, user, request, or event-name
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labels that could create unbounded cardinality.
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Metrics are local to each BEAM process. Discover and scrape every web pod or
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container as a distinct target and preserve Prometheus's `instance` label. A
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request through the load-balanced public route reaches only one replica and is
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therefore useful as an authorization/smoke check, not as a cluster-wide
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aggregate.
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The isolated load project includes a local observability profile:
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```bash
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./scripts/load-stack-up.sh
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./scripts/observability-run.sh local-observability
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```
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The run script refuses the staging project, validates every current web
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container's Compose labels, and writes a `file_sd` target for each observed
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internal IP. Prometheus reads the Bearer value from a mode-`0600` runtime file,
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not a tracked config or URL. Its direct request includes the internal
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`X-Forwarded-Proto: https` signal required by the application's production SSL
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rewrite while preserving the target's own `instance` label.
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Prometheus, Alertmanager, and Grafana are pinned by tag and digest. Their host
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ports default to Docker-assigned values bound only to `127.0.0.1`; the run
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prints the observed URLs. Grafana uses the random admin password generated in
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ignored `.env.load`, disables anonymous signup, update checks, suggested plugin
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installation, and its unused built-in alert engine. The Prometheus datasource
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and four-panel dashboard are provisioned from tracked files.
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The verification stops exactly one scoped load web container. The
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`WhoNeedHelpWebReplicaUnavailable` rule is based only on the factual
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`up == 0` result; it is a local failure drill, not an invented latency,
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capacity, or production SLO threshold. The script requires both firing and
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resolved webhook payloads from Alertmanager, starts the same container, waits
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for every direct target, and compares read-only database counts before and
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after. Evidence is retained in `output/observability/` without the metrics or
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Grafana secrets.
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Stop only the monitoring services with:
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```bash
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./scripts/observability-stop.sh
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```
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Prometheus/Grafana/Alertmanager retention, production notification
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destinations, production availability, and measured alert policies remain
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deployment decisions. In Kubernetes, put the metrics token in
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`existingSecret`; configure the external scraper to send it as a Bearer token.
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## Rollback boundary
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The release image is immutable and migrations run as a separate one-shot role.
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Before a schema rollout, create and restore-test a current backup. Application
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rollback and database migration rollback are separate decisions: do not run an
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Ecto down migration merely because an image is rolled back. Inspect the exact
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migration and compatibility boundary first.
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The repository intentionally does not ship an automatic destructive production
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restore command.
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