Javad

Posted on Jan 2

DevOps Tooling Masterclass — Complete Practical Guide for Engineers

#programming #tutorial #devops #discuss

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Docker

What it is
Docker is a containerization platform that packages applications and their dependencies into lightweight, portable containers that run consistently across environments.
Who it’s for
Developers, DevOps engineers, SREs, QA teams, and anyone who needs reproducible environments.
Suitable project sizes
All sizes: Small → Enterprise. Essential for teams adopting microservices or CI/CD.
What it’s good for
Reproducible builds, local development parity, packaging microservices, CI runners, and lightweight isolation.
Advantages
Fast startup and small images.
Ecosystem: Docker Hub, Compose, tooling.
Portable across clouds and CI systems.
Disadvantages
Image bloat if not optimized.
Security surface (privileged containers, misconfigured images).
Requires learning container networking and storage.
Installation (quick)
Linux (Ubuntu):
bash sudo apt update sudo apt install -y ca-certificates curl gnupg lsb-release curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg echo \ "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] \ https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null sudo apt update sudo apt install -y docker-ce docker-ce-cli containerd.io sudo usermod -aG docker $USER
macOS/Windows: Install Docker Desktop from docker.com.
Basic usage
Build and run:
bash docker build -t myapp:dev . docker run --rm -p 8080:8080 myapp:dev
Inspect:
bash docker ps docker logs <container> docker exec -it <container> /bin/sh
Intermediate usage
Multi‑stage Dockerfile to reduce image size:
`dockerfile
FROM golang:1.20 AS builder
WORKDIR /app
COPY . .
RUN CGO_ENABLED=0 go build -o app

FROM gcr.io/distroless/static
COPY --from=builder /app/app /app
ENTRYPOINT ["/app"]
`

Use named volumes and networks: bash docker network create app-net docker volume create app-data docker run -d --name db --network app-net -v app-data:/var/lib/postgres postgres

Advanced usage
Image scanning (Trivy), signing (cosign), and vulnerability policies in CI.
BuildKit and cache mounts for fast CI builds: bash DOCKERBUILDKIT=1 docker build --secret id=GITTOKEN,src=.git-credentials .
Runtime hardening: read‑only rootfs, drop capabilities, seccomp profiles: bash docker run --read-only --cap-drop=ALL --security-opt seccomp=/path/seccomp.json myapp

Docker Compose

What it is
A tool to define and run multi‑container Docker applications using a YAML file (docker-compose.yml).
Who it’s for
Developers and small teams who want to orchestrate multi‑container stacks locally or in simple deployments.
Suitable project sizes
Small → Medium projects and local development for larger projects.
What it’s good for
Local orchestration, service composition, quick integration testing, and simple CI jobs.
Advantages
Simple YAML syntax.
Easy to spin up full stacks (DB, cache, app).
Supports overrides for dev vs prod.
Disadvantages
Not a production orchestrator at scale (use Kubernetes for that).
Limited scheduling and resilience features.
Installation
Docker Compose is bundled with Docker Desktop. On Linux:
bash sudo curl -L "https://github.com/docker/compose/releases/latest/download/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose sudo chmod +x /usr/local/bin/docker-compose
Basic usage
docker-compose.yml example:
`yaml
version: "3.8"
services:
web:
build: .
ports:
- "8080:8080" depends_on:
- db db: image: postgres:15 environment: POSTGRES_PASSWORD: example Start:bash docker-compose up --build `
Intermediate usage
Use docker-compose.override.yml for dev settings.
Use named volumes and networks.
Healthchecks and restart policies:
yaml healthcheck: test: ["CMD", "curl", "-f", "http://localhost:8080/health"] interval: 30s retries: 3 restart: unless-stopped
Advanced usage
Use Compose v2 with compose CLI and docker compose for improved features.
Deploy stacks to Docker Swarm with docker stack deploy (Compose file compatibility).
Integrate Compose with CI to run integration tests in ephemeral environments.

Kubernetes

What it is
A production‑grade container orchestration platform for deploying, scaling, and managing containerized applications.
Who it’s for
Platform teams, SREs, and organizations running microservices at scale.
Suitable project sizes
Medium → Enterprise and large distributed systems.
What it’s good for
Automated scaling, self‑healing, rolling updates, service discovery, and multi‑tenant clusters.
Advantages
Rich API and ecosystem.
Declarative desired state and controllers.
Works across clouds and on‑prem.
Disadvantages
Operational complexity and steep learning curve.
Resource overhead and cluster management burden.
Installation (local & cloud)
Local: minikube, kind, or k3s for lightweight clusters.
`bash

kind
curl -Lo ./kind https://kind.sigs.k8s.io/dl/v0.20.0/kind-linux-amd64
chmod +x ./kind
./kind create cluster
`

Cloud: managed services (EKS, GKE, AKS) or kubeadm for on‑prem.

Basic usage
Deploy a simple app:
yaml apiVersion: apps/v1 kind: Deployment metadata: { name: web } spec: replicas: 3 selector: { matchLabels: { app: web } } template: metadata: { labels: { app: web } } spec: containers: - name: web image: myapp:latest ports: [{ containerPort: 8080 }]
bash kubectl apply -f deployment.yaml kubectl get pods kubectl port-forward svc/web 8080:8080
Intermediate usage
Use ConfigMaps and Secrets for configuration.
Horizontal Pod Autoscaler (HPA) and resource requests/limits:
bash kubectl autoscale deployment web --cpu-percent=70 --min=2 --max=10
Use readiness and liveness probes.
Advanced usage
Operators and CRDs for custom controllers.
Multi‑cluster and service mesh (Istio, Linkerd) for traffic control and observability.
GitOps workflows (ArgoCD, Flux) for declarative cluster management.
Pod security policies, network policies, and RBAC hardening.

YAML (YAML Ain’t Markup Language)

What it is
A human‑friendly data serialization format widely used for configuration (Kubernetes manifests, CI pipelines, Compose files).
Who it’s for
Anyone writing configuration files: DevOps, SREs, developers.
Suitable project sizes
All sizes; used everywhere from small projects to enterprise.
What it’s good for
Readable configuration, hierarchical data, and templating with tools.
Advantages
Human readable, supports comments, anchors, and aliases.
Widely supported.
Disadvantages
Indentation sensitive (error prone).
Complex features (anchors) can be misused.
Not ideal for binary data.
Installation
No installation; use YAML parsers in your language (PyYAML, ruamel.yaml, js-yaml).
Basic usage
Example:
yaml app: name: myapp replicas: 3 database: host: db.local port: 5432
Intermediate usage
Use anchors and aliases:
`yaml
defaults: &defaults
timeout: 30
retries: 3

service:
<<: *defaults
endpoint: /api
`

Validate with yamllint and schema validation (JSON Schema).

Advanced usage
Use templating (Helm, ytt, Kustomize) for parameterized manifests.
Use strict schema validation and CI checks to prevent invalid manifests.
Convert YAML to JSON for programmatic processing.

n8n

What it is
n8n is an open‑source workflow automation tool (no/low‑code) for connecting APIs, services, and automating tasks with visual flows.
Who it’s for
Automation engineers, product teams, and non‑dev users who need integrations without heavy engineering.
Suitable project sizes
Small → Medium teams; can be used in enterprise with self‑hosting and governance.
What it’s good for
ETL tasks, webhook orchestration, SaaS integrations, and business automation.
Advantages
Visual flow editor, many prebuilt connectors.
Self‑hostable and extensible with custom nodes.
Disadvantages
Complex flows can become hard to maintain.
Not a replacement for full ETL platforms for very large data volumes.
Installation
Docker Compose quick start:
`yaml
version: '3'
services:
n8n:
image: n8nio/n8n
ports:
- "5678:5678" environment:
- N8NBASICAUTH_ACTIVE=true
- N8NBASICAUTH_USER=user
- N8NBASICAUTH_PASSWORD=pass volumes:
- ./n8n:/home/node/.n8n ` docker compose up -d
Basic usage
Open http://localhost:5678, create a workflow, add a trigger (Webhook), add actions (HTTP request, Slack, Gmail).
Intermediate usage
Use environment variables for credentials, use the built‑in queue for concurrency, and create reusable sub‑workflows.
Advanced usage
Scale with multiple workers and Redis queue, implement custom nodes in TypeScript, secure with OAuth credentials and role‑based access, and integrate with Git for versioning flows.

RabbitMQ

What it is
A mature message broker implementing AMQP (Advanced Message Queuing Protocol) for reliable messaging.
Who it’s for
Teams needing reliable queuing, task distribution, and pub/sub with complex routing.
Suitable project sizes
Small → Enterprise; excellent for medium and large systems.
What it’s good for
Task queues, RPC, event distribution, and decoupling services.
Advantages
Mature, stable, many client libraries.
Flexible routing (exchanges, bindings).
Management UI and plugins.
Disadvantages
Operational complexity at scale (clustering, mirrored queues).
Not ideal for extremely high throughput compared to Kafka.
Installation
Docker:
bash docker run -d --hostname rabbit --name rabbit -p 5672:5672 -p 15672:15672 rabbitmq:3-management
Or install via package manager.
Basic usage
Publish/consume with client libraries (Python pika, Node amqplib).
Example (Python):
python import pika conn = pika.BlockingConnection(pika.ConnectionParameters('localhost')) ch = conn.channel() ch.queuedeclare(queue='taskqueue', durable=True) ch.basicpublish(exchange='', routingkey='task_queue', body='hello')
Intermediate usage
Use durable queues, persistent messages, prefetch for consumer fairness:
python ch.basicqos(prefetchcount=1)
Use exchanges (direct, topic, fanout) for routing.
Advanced usage
Cluster with mirrored queues or quorum queues for HA.
Use federation or shovel for cross‑datacenter replication.
Monitor with Prometheus exporter and tune memory alarms and flow control.

Apache Kafka

What it is
A distributed streaming platform for high‑throughput, durable, ordered event streaming.
Who it’s for
Data engineers, platform teams, and organizations building event‑driven architectures and real‑time pipelines.
Suitable project sizes
Medium → Enterprise, especially for high throughput and long retention.
What it’s good for
Event streaming, log aggregation, stream processing, and durable message storage.
Advantages
High throughput and horizontal scalability.
Strong durability and retention semantics.
Rich ecosystem (Kafka Connect, Streams, ksqlDB).
Disadvantages
Operational complexity (Zookeeper or KRaft mode).
Higher latency for small message workloads vs brokers like RabbitMQ.
Installation
Quick start with Docker Compose (Confluent or Apache images). For production use a multi‑broker cluster and KRaft or Zookeeper.
Basic usage
Produce and consume with kafka-console-producer and kafka-console-consumer.
Java/Go/Python clients for application integration.
Intermediate usage
Use partitions and keys for ordering and parallelism.
Configure retention, compaction, and replication factor.
Use Kafka Connect for connectors to databases and sinks.
Advanced usage
Use Kafka Streams or ksqlDB for stream processing.
Deploy multi‑region replication (MirrorMaker 2).
Tune broker configs: num.io.threads, log.segment.bytes, and disk throughput.
Monitor with Cruise Control and Prometheus exporters.

HAProxy

What it is
A high‑performance TCP/HTTP load balancer and reverse proxy.
Who it’s for
SREs and platform teams needing reliable L4/L7 load balancing.
Suitable project sizes
Small → Enterprise; widely used in production.
What it’s good for
Load balancing, SSL termination, health checks, and traffic routing.
Advantages
Extremely fast and battle‑tested.
Rich ACLs and routing rules.
Low resource footprint.
Disadvantages
Configuration can be terse and error‑prone.
Less dynamic than service meshes without additional tooling.
Installation
Install via package manager (apt install haproxy) or Docker image.
Basic usage
haproxy.cfg simple example:
`cfg
frontend http-in
bind *:80
default_backend servers

backend servers
server s1 10.0.0.1:8080 check
server s2 10.0.0.2:8080 check
`
Start service and check logs.

Intermediate usage
Use ACLs for path‑based routing and header checks.
Configure SSL termination and HTTP/2.
Use stick tables for session persistence and rate limiting.
Advanced usage
Dynamic configuration via Runtime API or Consul integration.
Use Lua scripts for custom logic.
Integrate with Prometheus exporter for metrics and health monitoring.

Traefik

What it is
A modern, dynamic reverse proxy and load balancer designed for microservices and cloud native environments.
Who it’s for
Teams using Kubernetes, Docker, or dynamic service registries (Consul, etcd).
Suitable project sizes
Small → Enterprise, especially for dynamic environments.
What it’s good for
Automatic service discovery, Let’s Encrypt integration, and dynamic routing.
Advantages
Auto‑discovery of services and automatic certificate management.
Native integration with Kubernetes Ingress and CRDs.
Dashboard and metrics.
Disadvantages
Less low‑level control than HAProxy for some edge cases.
Complexity when customizing advanced routing logic.
Installation
Use Helm for Kubernetes or Docker image for Compose.
Basic usage
In Kubernetes, create an IngressRoute or use annotations on Ingress.
Traefik will automatically route to services and obtain TLS certs.
Intermediate usage
Use middleware for authentication, rate limiting, and headers.
Configure TCP routers for non‑HTTP services.
Advanced usage
Use Traefik Pilot for centralized management.
Integrate with service mesh or use Traefik Mesh for service‑to‑service routing.
Implement complex routing with dynamic configuration providers.

Elasticsearch

What it is
A distributed search and analytics engine built on Lucene for full‑text search, metrics, and logs.
Who it’s for
Data engineers, SREs, and teams needing search, observability, or analytics.
Suitable project sizes
Medium → Enterprise; scales horizontally.
What it’s good for
Log analytics, full‑text search, metrics indexing, and dashboards (with Kibana).
Advantages
Powerful search capabilities and aggregations.
Ecosystem: Beats, Logstash, Kibana.
Scales horizontally.
Disadvantages
Resource intensive (memory/disk).
Operational complexity (shards, replicas, index lifecycle).
Security and licensing considerations for advanced features.
Installation
Docker image or official packages. For production, use a multi‑node cluster and configure JVM heap.
Basic usage
Index documents via REST API:
bash curl -X POST "localhost:9200/myindex/_doc" -H 'Content-Type: application/json' -d '{"message":"hello"}' curl "localhost:9200/myindex/_search?q=hello"
Intermediate usage
Use index templates, ILM (Index Lifecycle Management), and analyzers for language processing.
Use Logstash or Beats to ingest logs and metrics.
Advanced usage
Tune shard counts, replica settings, and refresh intervals.
Use cross‑cluster search, snapshot/restore to S3, and secure clusters with TLS and RBAC.
Monitor with Elastic Stack and Prometheus exporters.

Kibana

What it is
A visualization and exploration UI for Elasticsearch data (dashboards, discover, and dev tools).
Who it’s for
SREs, analysts, and developers who need dashboards and log exploration.
Suitable project sizes
Small → Enterprise; used wherever Elasticsearch is used.
What it’s good for
Dashboards, ad‑hoc queries, and visualizing logs and metrics.
Advantages
Tight integration with Elasticsearch.
Powerful visualizations and Canvas for custom reports.
Disadvantages
Can be heavy for large datasets; requires Elasticsearch tuning.
Licensing for advanced features.
Installation
Docker image or package; configure kibana.yml to point to Elasticsearch.
Basic usage
Open Kibana UI, create index patterns, and build visualizations.
Intermediate usage
Use Timelion, Vega, and Canvas for advanced visualizations.
Create alerts and integrate with Watcher (or Alerting in Kibana).
Advanced usage
Use Kibana Spaces for multi‑tenant dashboards.
Automate dashboard provisioning via saved objects API.
Secure with SSO and role‑based access.

Logstash

What it is
A data processing pipeline that ingests, transforms, and forwards logs and events (part of the Elastic Stack).
Who it’s for
Teams ingesting logs from many sources needing complex parsing and enrichment.
Suitable project sizes
Medium → Enterprise.
What it’s good for
Parsing, enriching, and routing logs to Elasticsearch or other sinks.
Advantages
Powerful plugin ecosystem for inputs, filters, and outputs.
Good for complex parsing (grok, date, geoip).
Disadvantages
Memory heavy; can be slower than lightweight agents (Beats).
Operational overhead.
Installation
Docker image or package; configure logstash.conf.
Basic usage
Example pipeline:
conf input { beats { port => 5044 } } filter { grok { match => { "message" => "%{COMBINEDAPACHELOG}" } } } output { elasticsearch { hosts => ["localhost:9200"] } }
Intermediate usage
Use persistent queues, dead letter queues, and pipeline workers for throughput.
Use conditional filters and mutate operations.
Advanced usage
Scale with multiple Logstash instances and load balancers.
Use central pipeline management and monitoring in X‑Pack.
Optimize JVM settings and pipeline batch sizes.

Prometheus

What it is
A metrics collection and alerting system designed for reliability and dimensional data model.
Who it’s for
SREs and platform teams needing time‑series metrics and alerting.
Suitable project sizes
Small → Enterprise; excellent for cloud native environments.
What it’s good for
Scraping metrics, alerting, and powering Grafana dashboards.
Advantages
Pull model, powerful PromQL, and many exporters.
Designed for reliability and federation.
Disadvantages
Not ideal for long‑term storage without remote write (Thanos, Cortex).
Cardinality explosion risk if labels are misused.
Installation
Download binary or use Docker image. For Kubernetes, use the Prometheus Operator.
Basic usage
Configure prometheus.yml with scrape targets:
`yaml
scrape_configs:
- job_name: 'node' static_configs:
  - targets: ['localhost:9100'] `
Start Prometheus and query metrics in the UI.
Intermediate usage
Use exporters (nodeexporter, blackboxexporter), instrument apps with client libraries, and create alerts in Alertmanager.
Advanced usage
Use Thanos or Cortex for long‑term storage and global query.
Tune scrape intervals, retention, and use relabeling to control cardinality.
Implement alerting runbooks and automated remediation.

Grafana

What it is
A visualization and dashboarding platform for metrics, logs, and traces.
Who it’s for
SREs, developers, and analysts building observability dashboards.
Suitable project sizes
Small → Enterprise.
What it’s good for
Dashboards, alerting, and unified views across Prometheus, Elasticsearch, Loki, and other data sources.
Advantages
Rich panel types, templating, and alerting.
Pluggable data sources and plugins.
Disadvantages
Large dashboards can be heavy; requires data source tuning.
Installation
Docker image or package; configure data sources in UI or via provisioning.
Basic usage
Add Prometheus as a data source, create a dashboard, and add panels with PromQL queries.
Intermediate usage
Use variables, templating, and dashboard provisioning via YAML.
Configure alerting channels (Slack, PagerDuty).
Advanced usage
Use Grafana Enterprise features for reporting and teams.
Build custom plugins and panels.
Use Grafana Loki for log aggregation and correlate logs with metrics.

Zabbix

What it is
An enterprise monitoring solution for infrastructure and applications with agent‑based and agentless checks.
Who it’s for
Enterprises needing centralized monitoring, alerting, and inventory.
Suitable project sizes
Medium → Enterprise.
What it’s good for
Host and service monitoring, SNMP, and long‑term metrics.
Advantages
Rich templates, auto‑discovery, and flexible alerting.
Good for mixed environments (network devices, servers).
Disadvantages
Heavier to operate than Prometheus for cloud native stacks.
UI and configuration complexity.
Installation
Use packages or Docker images; requires database (MySQL/Postgres) and web server.
Basic usage
Install agent on hosts, create hosts and templates in the UI, and configure triggers.
Intermediate usage
Use low‑level discovery, custom checks, and escalations.
Integrate with external alerting and ticketing.
Advanced usage
Scale with proxies, distributed monitoring, and high availability.
Use custom scripts and external checks for complex metrics.

Sentry

What it is
An error tracking and performance monitoring platform for applications.
Who it’s for
Developers and teams who need real‑time error reporting and performance insights.
Suitable project sizes
Small → Enterprise.
What it’s good for
Crash reporting, stack traces, release tracking, and performance monitoring.
Advantages
Quick integration with many SDKs.
Rich context (breadcrumbs, user info, tags).
Disadvantages
Data privacy and retention considerations.
Cost at scale for high event volumes.
Installation
SaaS at sentry.io or self‑host with Docker Compose (on‑prem).
Basic usage
Install SDK (e.g., sentry-sdk for Python) and initialize with DSN:
python import sentry_sdk sentry_sdk.init("https://<key>@sentry.io/<project>")
Intermediate usage
Configure release tracking, environment tags, and performance spans.
Use sampling to control event volume.
Advanced usage
Integrate with CI for source maps and deploy tracking.
Use advanced performance monitoring and custom transactions.

Keycloak

What it is
An open‑source identity and access management solution providing SSO, OAuth2, and OpenID Connect.
Who it’s for
Teams needing centralized authentication, SSO, and user federation.
Suitable project sizes
Medium → Enterprise.
What it’s good for
SSO, social login, LDAP/AD federation, and fine‑grained authorization.
Advantages
Feature rich and standards compliant.
Extensible with custom providers.
Disadvantages
Operational complexity and upgrade considerations.
UI and customization learning curve.
Installation
Docker image or distribution packages. For production, run in a cluster with a backing database.
Basic usage
Create a realm, clients, and users in the admin UI. Configure client credentials and redirect URIs.
Intermediate usage
Configure identity brokering (social logins), user federation (LDAP), and roles.
Use Keycloak adapters for applications.
Advanced usage
Customize themes, write custom SPI providers, and integrate with external identity providers.
Scale with clustering and external DB, secure with TLS and fine‑grained policies.

OAuth2 Server (generic)

What it is
An OAuth2 authorization server issues access tokens and manages client credentials and scopes.
Who it’s for
Teams building APIs that require delegated authorization.
Suitable project sizes
Small → Enterprise.
What it’s good for
API authorization, delegated access, and token management.
Advantages
Standardized flows (authorization code, client credentials, refresh tokens).
Interoperable across clients and services.
Disadvantages
Security sensitive; misconfiguration leads to vulnerabilities.
Token lifecycle and revocation complexity.
Installation
Use Keycloak, Hydra (ORY), or Auth0 as implementations.
Basic usage
Register clients, configure redirect URIs, and implement authorization code flow in your app.
Intermediate usage
Use PKCE for public clients, refresh tokens, and scope management.
Implement token introspection and revocation endpoints.
Advanced usage
Implement fine‑grained consent screens, dynamic client registration, and token exchange.
Use JWT signing and rotation, and integrate with identity federation.

HashiCorp (Vault, Consul, Terraform)

What it is
A family of tools: Vault (secrets management), Consul (service discovery, KV), and Terraform (infrastructure as code).
Who it’s for
Platform teams, SREs, and infra engineers.
Suitable project sizes
Medium → Enterprise.
What it’s good for
Secrets lifecycle, service discovery, and reproducible infra provisioning.
Advantages
Strong security model (Vault), declarative infra (Terraform), and service mesh features (Consul).
Large ecosystem and providers.
Disadvantages
Operational complexity and state management (Terraform state).
Vault requires secure storage and unsealing processes.
Installation
Binaries or Docker images; for Vault/Consul use HA mode with storage backend.
Basic usage
Vault: vault kv put secret/myapp password=... and read with vault kv get.
Terraform: write .tf files and terraform init && terraform apply.
Intermediate usage
Use Vault dynamic secrets (database credentials), Consul service mesh, and Terraform modules for reuse.
Advanced usage
Automate Vault unseal with KMS, use Terraform Cloud/Enterprise for remote state and policy, and integrate Consul Connect for mTLS service mesh.

OpenSSL CLI

What it is
A command‑line toolkit for TLS/SSL, certificate generation, and cryptographic operations.
Who it’s for
Security engineers, DevOps, and anyone managing TLS certificates.
Suitable project sizes
All sizes.
What it’s good for
Generating keys, CSRs, self‑signed certs, and debugging TLS connections.
Advantages
Ubiquitous and powerful.
Supports many crypto primitives.
Disadvantages
Complex command syntax; easy to misuse.
Installation
Usually preinstalled on Linux; otherwise apt install openssl.
Basic usage
Generate key and self‑signed cert:
bash openssl genrsa -out key.pem 2048 openssl req -new -x509 -key key.pem -out cert.pem -days 365
Intermediate usage
Create CSR and sign with CA, convert formats (PEM ↔ DER), and inspect certs:
bash openssl x509 -in cert.pem -text -noout openssl pkcs12 -export -out keystore.p12 -inkey key.pem -in cert.pem
Advanced usage
Manage OCSP, CRL, and certificate chains.
Use s_client to debug TLS handshakes and cipher negotiation:
bash openssl s_client -connect example.com:443 -servername example.com

GitHub Actions

What it is
A CI/CD platform integrated with GitHub for automating workflows triggered by repository events.
Who it’s for
Developers and teams using GitHub for source control.
Suitable project sizes
Small → Enterprise (GitHub Enterprise).
What it’s good for
CI builds, tests, deployments, and automation tied to Git events.
Advantages
Tight GitHub integration, marketplace actions, and matrix builds.
Hosted runners and self‑hosted runner options.
Disadvantages
Hosted runner limits and billing for minutes.
Secrets management and runner security considerations.
Installation
No install for GitHub SaaS; add .github/workflows/*.yml to repo.
Basic usage
Example workflow:
`yaml
name: CI
on: [push]
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- name: Build run: make build `
Intermediate usage
Use matrix builds, caching, and artifacts.
Use environments and protection rules for deployments.
Advanced usage
Self‑hosted runners for specialized hardware.
Composite actions, reusable workflows, and advanced secrets (OIDC) for cloud auth.

GitLab CI

What it is
A CI/CD system built into GitLab with pipelines defined in .gitlab-ci.yml.
Who it’s for
Teams using GitLab for SCM and CI/CD.
Suitable project sizes
Small → Enterprise (GitLab EE).
What it’s good for
Full CI/CD pipelines, multi‑stage builds, and integrated security scanning.
Advantages
Integrated with GitLab features (MRs, issues).
Powerful pipeline features and runners.
Disadvantages
Runner management for self‑hosted setups.
Complexity for large pipelines.
Installation
GitLab SaaS or self‑hosted; install GitLab Runner on build hosts.
Basic usage
.gitlab-ci.yml example:
yaml stages: [build, test] build: stage: build script: make test: stage: test script: make test
Intermediate usage
Use caching, artifacts, and parallel jobs.
Use protected branches and environments.
Advanced usage
Use dynamic child pipelines, multi‑project pipelines, and security scanning (SAST/DAST).
Autoscale runners with Kubernetes executor.

N8H (The future of Automation)

Note: N8H is presented here as a conceptual next‑generation automation platform inspired by n8n and modern orchestration patterns. Treat this as a forward‑looking design and practical checklist for building or evaluating future automation platforms.

What it is
A hypothetical, unified automation platform combining visual workflows, event streaming, policy‑driven automation, and AI‑assisted orchestration.
Who it’s for
Platform teams, enterprise automation architects, and organizations seeking low‑code automation at scale.
Suitable project sizes
Medium → Enterprise; designed for cross‑team automation and governance.
What it’s good for
End‑to‑end automation: event ingestion, decisioning, human approvals, and closed‑loop remediation.
Advantages
Unified control plane for automation, observability, and governance.
Extensible connectors and policy enforcement.
Disadvantages
Complexity and integration effort.
Requires strong governance and RBAC.
Installation (conceptual)
Deploy as microservices on Kubernetes with operator for lifecycle.
Use message bus (Kafka) and workflow engine (temporal/Zeebe) under the hood.
Basic usage
Visual flow builder, connect SaaS apps, and create simple triggers and actions.
Intermediate usage
Use event streams, idempotent actions, and versioned flows.
Integrate with secrets manager and identity provider.
Advanced usage
Policy as code, automated remediation playbooks, and AI‑assisted flow generation.
Multi‑tenant governance, audit trails, and compliance reporting.

Final recommendations and patterns

Start small: use Docker + Compose for local dev, then adopt Kubernetes for production.
Observability: pair Prometheus + Grafana for metrics, ELK (Elasticsearch + Logstash + Kibana) or Loki for logs, and Sentry for errors.
Messaging: choose RabbitMQ for task queues and Kafka for high‑throughput event streaming.
Ingress & routing: Traefik for dynamic environments, HAProxy for raw performance and control.
Security & identity: Keycloak for SSO and Vault for secrets.
CI/CD: GitHub Actions for GitHub users, GitLab CI for GitLab users; use self‑hosted runners for special needs.
Automation: n8n for quick integrations; design future automation platforms (N8H) with event streams, policy, and governance in mind.

I hope you enjoy it! Have nice times!