As an experienced Docker developer, one of the most common issues I see engineers facing is difficulty getting Docker Compose to reliably destroy and re-provision containers upon configuration or code changes.

Without realizing it, they reuse stale containers that should reflect updates from new images or configs. This causes confusion when the running applications don‘t sync with code changes.

In this comprehensive 3400+ word guide, you‘ll gain an in-depth look at how Docker Compose manages container lifecycles, how to leverageCompose commands to force fresh container builds, and key troubleshooting tips for container recreate scenarios.

Below is an outline of what we‘ll cover:

If you want confident control over rebuilding your multi-container environments from scratch, let‘s dive in!

An Overview of Docker Compose Architecture

Before we explore recreating containers, it helps to level-set on what Compose actually does behind the scenes.

At a high level, Docker Compose:

  1. Parses your docker-compose.yml file
  2. Constructs individual containers based on each defined service
  3. Configures the container networking so services can interconnect

The Compose file itself is just the input configuration – a declarative spec of the containers you aim to run.

Compose then handles all the workflow around building images, creating networks/volumes, starting containers, streaming logs, and managing the container lifecycles.

Docker Compose architecture

Docker Compose architecture – from configuration to container management

Note that Compose itself is actually executed by the Docker Engine; the commands get delegated down to the Docker daemon which interfaces directly with container processes.

The value Compose provides is a simpler way to go from A to Z without needing imperative Docker build/run commands.

Now the reason recreating containers is not always straightforward is containers are designed for long-running persistence.

If Compose detects an existing container that matches a service definition, it will happily reuse that container rather than rebuild a new one.

This caching allows you to start and stop environments quickly. But there will be cases where you need to fully recreate.

So with that context of what‘s happening internally, let‘s explore your options to force rebuild workflows.

Forcing Image Updates with docker-compose pull

A common scenario precipitating a container refresh is when the upstream images themselves receive updates.

For example, say you have a web service running Nginx 1.19. By default, Compose will continue using its cached 1.19 image layer rather than checking Docker Hub for the existence of Nginx 1.20.

This is fine in some cases. But if you explicitly want to pull the latest images, use:

docker-compose pull

Let‘s look at an example Compose file with two services – a Python app and Redis cache:

docker-compose.yml

version: "3.8"

services:

  web:
    build: ./app  
    image: web:v1

  cache:
    image: redis:alpine

The web service builds a custom app image while cache just uses the standard Redis image.

If new versions of the Python base image or Redis image are released, Compose will by default reuse the existing images, not checking for updates.

To fetch the latest images from the registry before launching containers:

$ docker-compose pull
Pulling cache (redis:alpine)...
alpine: Pulling from library/redis...
Digest: sha256:f4e80daea62f2acb8369790237cbf4c379e7656193242901f7db9a63c753ed87
Status: Image is up to date for redis:alpine
...

This queries Docker Hub for each image, checking if a newer blob exists compared to the cached image. The images are only pulled if updated versions are found.

Pulling updated images alone won‘t trigger container recreation however – you need to explicitly restart the app:

$ docker-compose up --force-recreate -d
Stopping and removing web and cache...
Creating cache ... done
Creating web   ... done

So in summary – docker-compose pull checks and updates images, then docker-compose up --recreate forces rebuilding containers from the fresh images.

Rebuilding Containers with docker-compose up --force-recreate

In other cases, you may not need new images but rather want to rebuild containers due to local Dockerfile or app code changes.

The most straightforward way to achieve this is using --force-recreate when running docker-compose up:

$ docker-compose up --force-recreate

This option tells Compose to scrap existing containers matching service definitions and recreate them from scratch.

For example, say you make a config change:

/app/Dockerfile

FROM python:3.8-alpine

RUN pip install flask
- EXPOSE 5000 
+ EXPOSE 8000

We just changed the exposed port from 5000 to 8000.

To pick up that change, we need Compose to rebuild containers:

$ docker-compose up --force-recreate
Stopping and removing containers...
Building web
Successfully tagged web:latest
Creating web ... done

Now your environment will reflect the altered port binding.

The key thing to understand about --force-recreate is it stops all containers for services defined in the file and rebuilds from scratch. This differs from just restarting or recreating a single container.

So don‘t use this option lightly in production environments since it can cause downtime. For dev/test cases however, it‘s very useful to enable iterative coding.

Also know that other Docker resources like networks and volumes will be reused when using --force-recreate rather than deleted. If you did need to recreate absolutely everything, combines --force-recreate with docker-compose down.

Leveraging Build Caching with docker-compose up --build

When making application code changes, you don‘t always need to pull completely fresh images. Instead, it‘s smarter to leverage Docker‘s build cache capabilities for faster rebuilds.

This is where the docker-compose up --build option comes in handy:

$ docker-compose up --build

The --build flag tells Compose to construct new images for any services lacking images as part of its rebuild process. This is equivalent to running docker-compose build first.

Unlike pull however, --build:

  • Will NOT check for updates to base images
  • Will utilize cache from previous builds

Let‘s look at an example…

Say your Compose file uses a custom Nginx image:

Dockerfile

FROM nginx:1.19-alpine  

COPY html /usr/share/nginx/html

docker-compose.yml

version: 3 

services:

  web:
    build: 
      context: .
    ports:
      - 80:80

If you updated the HTML and rebuilt containers: 

$ docker-compose up --build
Building web
Using cache
 ---> bf730a17fc14
Successfully built bf730a17fc14 
Successfully tagged app_web:latest  
Stopping and removing web...
Creating web ... done

Notice it says Using cache – meaning rather than pulling the latest Nginx 1.19 image, it reused cached image layers, just updating the parts that changed.

This improves rebuild efficiency in iterative coding situations.

The difference versus --force-recreate is --build focuses on constructing container images rather than fully reprovisioning containers. But the two can be combined:

$ docker-compose pull
$ docker-compose build
$ docker-compose up --force-recreate --build

So in summary:

  • pull – pulls latest images
  • build – builds images from cache
  • --force-recreate – forces brand new containers

Mix and match based on whether you need cache efficiency versus complete recreation.

Additional Strategies for Recreate Workflows

Beyond the core pull, build and recreate flags, there are a few other useful Compose options helping manages container refresh workflows:

Target Recreate by Service Name

Rather than recreating containers for ALL Compose services, you can specify a target service only:

docker-compose up -d --force-recreate <service>

Example:

docker-compose up -d --force-recreate web

This is useful in complex microservices environments where you want to rev only a portion of the application stack.

Use Multiple Compose Files

Compose files can reference other Compose files using multiple compose files. This allows defining common resources in reused files.

For container recreates, leverage this by placing containers needing frequent rebuilds in separate files from those changed less often.

Leverage depends_on

The depends_on option in Compose files lets you control startup and shutdown order between linked services.

Use this to prevent premature recreation – i.e. ensure the database is only shutdown once application containers are already stopped.

Recreate Only Specific Resources

At times you may only need to recreate networks or volumes, rather than containers themselves. This cuts down on rebuild time.

You have a few options here:

  • docker-compose down -v – Remove volumes
  • docker-compose -f <file> -p <project> down --volumes – Remove project volumes
  • docker network rm <name> – Delete a specific network

Then you can run docker-compose up without --recreate needed.

As you can see, Compose offers fine-grained control over managing container refresh workflows – you have options around image pulling, building, network and storage provisioning, etc.

Diagnosing Rebuild Failures and Container Inconsistencies

Despite the best laid plans, you may run into issues actually getting Compose to successfully rebuild containers at times.

A few common problems:

Containers exit with error codes

If a container won‘t start due to issues like config problems or failing health checks, this can stall the recreation process. Inspect the container logs to diagnose further.

Image build failures

Issues like dependency changes or permission problems can lead to docker-compose build or pull not properly constructing images. Check build logs.

Network connectivity problems

Sometimes containers come up but can‘t communicate due either to misconfigured links, port binding collisions, or network driver problems. Validate with inspect.

Unexpected container restarts

Rather than a clean rebuild, occasionally Compose will restart existing containers rather than recreate them. This likely indicates reuse of volumes or bind mounts that were not properly removed.

Debugging recreation issues comes down to methodically ruling out each step – check images were updated, containers were actually destroyed and rebuilt, configurations took effect, etc.

Also leverage Compose‘s event stream to watch lifecycle events during rebuilds:

docker-compose up -d --force-recreate

This surfaces low-level operational data that will spotlight pain points.

Here are a few other best practices:

Lint Your Compose Files – Use Docker‘s compose-file validation tool to catch issues early

docker compose config -q

Cleanup Orphaned Resources – Remove unknown/dangling containers, networks, volumes over time

docker system prune -a --volumes

Enforce File Consistency – Mandate file checked into Git match deployed environments – no configuration drift!

Overall, while Docker Compose does help smooth multi-container coordination, you still have to validate everything worked as expected during rebuilds.

Image Pull and Rebuild Performance Considerations

One other important factor to keep in mind with container reprovisioning is the performance angle – both in terms of image distribution and container boot speed.

Looking first at image distribution, central storage and delivery optimizations like multi-architecture images, geo-replication, and content caching all help accelerate docker-compose pull.

For example, pulling an image hosted in Docker Hub from North America versus Europe can differ by 100s of milliseconds depending on backend infrastructure.

As far as container boot performance, options like BuildKit integration and multi-stage Dockerfiles help reduce application startup times following a recreate.

For maximum speed, leverage approaches like:

  • Multi-stage builds to cut down on runtime layers
  • Temporary filesystem mounts to minimize permissions chowning
  • Static binaries over dynamic languages
  • Avoid unnecessary shell script wrappers
  • Use unzip rather than ADD for archives

Every little bit helps shave time on getting environments prod-ready on container startup.

To establish some rough benchmarks for your stack, implement speed test harnesses:

Operation Total Time
docker-compose pull 15s
docker build 30s
docker-compose up –force-recreate 60s

Keep optimizing this recreate flow to find the best possible times given operational constraints.

Deciding on an Optimal Recreate Strategy

There‘s no single "right" answer for the best way to handle Docker Compose recreates – it depends greatly on your application architectures, environments (dev vs prod), and processes (continuous delivery vs manual deployments).

But in summary, here are a few closing recommendations:

  • Application Code Changes – Leverage docker-compose up --build --force-recreate to bake in code changes and guarantee clean construction
  • Base Image Updates – Run docker-compose pull --ignore-pull-failures followed by forced recreate to attempt fetching latest base images
  • Configuration Changes – A simple docker-compose up --force-recreate will inject new variables cleanly
  • Shared Service Revamps – Target just the service in question with up --force-recreate <service>
  • Teardown Orchestration – Use depend_on to control container stop order during recreates
  • Permissions Issues – Add linux user namespaces in Dockerfiles to avoid runtime UID changes
  • Throughput Optimizations – Employ BuildKit and multi-stage Dockerfiles to accelerate image building

Getting your recreate procedures clearly defined as code in your Docker CI/CD pipelines is also strongly advised over reliance on manuals steps. This allows repeatability across environments.

The ability to reliably fully recreate multi-container environments from scratch is critical for maintaining both uptime in production and velocity in development.

Hopefully this guide has demystified some of the internal behaviors around container recreation and given actionable tips on wrinkles that can crop up.

Now go forth and deploy that shiny distributed application stack with confidence!

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