Versionado y despliegue de releases
Comprenda las buenas prácticas para versionar releases, desplegar actualizaciones y gestionar reversiones en un entorno de producción.
Versionado y despliegue de releases es una lección gratuita de Erlang OTP: Distributed & Fault-Tolerant Systems Programming en CoddyKit. Esta es la lección 3 de 4. Puedes leer la lección completa abajo gratuitamente — luego la practicas en el navegador con un editor de código integrado y un tutor de IA 24/7. Forma parte de la ruta de aprendizaje de Erlang OTP: Distributed & Fault-Tolerant Systems Programming, y tu progreso se sincroniza en la web y la app de CoddyKit. El curso de Erlang OTP: Distributed & Fault-Tolerant Systems Programming incluye 4 lecciones en total.
Partes de esta lección aún no han sido traducidas y se muestran en inglés.
Why Version Your Releases?
When you build an Erlang application for production, it's bundled into a release. Just like any software, releases need clear version numbers.
Versioning helps you:
- Track changes over time.
- Identify specific builds.
- Manage compatibility with other systems.
- Plan for upgrades and rollbacks.
Erlang's Versioning System
In Erlang, versioning happens at different levels. Each individual application (an .app file) has its own version. The overall release (the .rel file) also has a version that typically reflects the entire bundle.
The vsn key in an .app file defines an application's version.
% my_app.app file (conceptual)
{application, my_app,
[{description, "My Erlang Application"},
{vsn, "1.0.0"},
{modules, [my_app_app, my_app_sup]},
{registered, []},
{applications, [kernel, stdlib]},
{mod, {my_app_app, []}},
{env, []}]}.Semantic Versioning (SemVer)
A widely adopted standard is Semantic Versioning (SemVer), typically formatted as MAJOR.MINOR.PATCH. It's a great practice to follow for your Erlang applications.
- MAJOR: Incremented for incompatible API changes.
- MINOR: Incremented for new functionality in a backward-compatible way.
- PATCH: Incremented for backward-compatible bug fixes.
This helps users understand the impact of an upgrade.
Applying SemVer in Erlang
You'll typically apply SemVer to your application's vsn in the .app file. When you create a release, its version (relvsn) often matches the main application's version or follows a similar scheme.
Tools like rebar3 manage these versions when building releases.
% my_app.app file
{application, my_app,
[{description, "My Erlang Service"},
{vsn, "1.2.3"},
{modules, [my_app_app, my_app_sup]},
{registered, []},
{applications, [kernel, stdlib]},
{mod, {my_app_app, []}},
{env, []}]}.Deployment Strategies Overview
Once you have a versioned Erlang release, how do you get it running in production? There are several strategies, depending on your system's requirements for uptime and complexity.
- Cold Deployment: Simplest, involves downtime.
- Hot Upgrades: Zero-downtime (covered in previous lesson).
- Blue/Green or Canary Deployments: More advanced, often used with orchestration tools.
Cold Deployment: Simple Restart
A cold deployment is the most straightforward method. You stop your currently running Erlang system completely, replace its files with the new release, and then start the new version.
This method always incurs downtime, making it suitable for systems where brief interruptions are acceptable.
# Stop the old release
/path/to/my_app/bin/my_app stop
# (Replace files with new release)
# Start the new release
/path/to/my_app/bin/my_app startHot Upgrades vs. Full Deployment
Recall from the previous lesson that hot code loading allows you to upgrade a running Erlang system without stopping it.
While powerful for applying patches or minor feature additions, hot upgrades are specific to changing *parts* of a running system. A full deployment often refers to the initial setup or a complete replacement of the entire release, sometimes involving a cold restart or more advanced traffic management.
The Importance of Rollbacks
Even with careful testing, new deployments can introduce unexpected issues. A robust deployment strategy always includes a plan for rollbacks.
A rollback means reverting your system to a previous, stable version if the new deployment fails or causes problems. This minimizes the impact of failures and restores service quickly.
Erlang's Rollback Mechanism
Erlang releases are designed to support rollbacks. When you perform a hot upgrade, Erlang generates an .relup script that describes how to move between versions. Crucially, it also knows how to reverse that script to go back.
Even with cold deployments, you can switch back to a previous release by managing your release directories and restarting the desired version.
# Example of a rollback command using release_handler
# This would typically be part of a custom script or release tool
% release_handler:install_release("my_app-1.1.0").
% release_handler:make_permanent("my_app-1.1.0").
# Alternatively, for cold deployment:
# /path/to/my_app_1.1.0/bin/my_app startTest Your Understanding
Order the steps for a typical cold deployment of an Erlang release.
Summary: Versioning & Deployment
You've learned about the critical aspects of release versioning and deployment in Erlang:
- Versioning: Use
vsnin.appfiles, ideally following SemVer (MAJOR.MINOR.PATCH), to track and manage changes. - Deployment: Understand cold deployment (with downtime) and its distinction from hot upgrades.
- Rollbacks: Always plan for reverting to a stable previous version to ensure system resilience.
These practices are key to managing robust Erlang applications in production!
Preguntas frecuentes
¿La lección «Versionado y despliegue de releases» es gratis?
Sí — el texto completo de «Versionado y despliegue de releases» es gratis para leer aquí en la web. Para practicarla de forma interactiva (editor de código integrado y tutor de IA 24/7) y desbloquear el resto del curso de Erlang OTP: Distributed & Fault-Tolerant Systems Programming, actualiza a CoddyKit PRO. El curso de Erlang OTP: Distributed & Fault-Tolerant Systems Programming incluye 4 lecciones en total.
¿Qué aprenderé en «Versionado y despliegue de releases»?
Comprenda las buenas prácticas para versionar releases, desplegar actualizaciones y gestionar reversiones en un entorno de producción. Practicas Erlang OTP: Distributed & Fault-Tolerant Systems Programming con código real que ejecutas directamente en el navegador, y un tutor de IA 24/7 responde tus preguntas mientras trabajas en la lección.
¿Necesito experiencia previa para empezar Erlang OTP: Distributed & Fault-Tolerant Systems Programming?
No se requiere experiencia previa. Erlang OTP: Distributed & Fault-Tolerant Systems Programming en CoddyKit está estructurado para principiantes hasta estudiantes avanzados, así que puedes empezar aquí o desde el inicio y avanzar a tu ritmo. Esta es la lección 3 de 4.
¿Cuánto tiempo toma la lección «Versionado y despliegue de releases»?
La mayoría de las lecciones de CoddyKit toman alrededor de 5–10 minutos. Cada una es compacta e interactiva, así que avanzas constantemente y retomas exactamente por donde dejaste en la web y la app.
¿Puedo escribir y ejecutar código en esta lección de Erlang OTP: Distributed & Fault-Tolerant Systems Programming?
Sí. Cada lección de Erlang OTP: Distributed & Fault-Tolerant Systems Programming incluye un editor de código integrado, así que escribes y ejecutas código real directamente en tu navegador y obtienes retroalimentación instantánea de IA — sin configuración local necesaria.
Todas las lecciones de este curso
- Creación de releases de Erlang
- Carga y actualización de código en caliente
- Versionado y despliegue de releases
- Configuración de releases y scripts de arranque