Why would I use this instead of Traefik for zero-downtime deployment?

andrewkangg

Andrew Kang-G

Posted on November 16, 2024

Why would I use this instead of Traefik for zero-downtime deployment?

First you need to look into a process summary of Docker-Blue-Green-Runner at this link,

https://github.com/patternhelloworld/docker-blue-green-runner

The following explains why I use Docker-Blue-Green-Runner…

  1. No Unpredictable Errors in Reverse Proxy and Deployment
  1. From Scratch
  • Docker-Blue-Green-Runner’s run.sh script is designed to simplify deployment: "With your .env, project, and a single Dockerfile, simply run 'bash run.sh'." This script covers the entire process from Dockerfile build to server deployment from scratch.

  • This means you can easily migrate to another server with just the files mentioned above.

  • In contrast, Traefik requires the creation and gradual adjustment of various configuration files, which can introduce the types of errors mentioned above.

  1. Focus on zero-downtime deployment on a single machine.
  • While Kubernetes excels in multi-machine environments with the support of Layer 7 (L7) technologies (I would definitely use Kubernetes in that case), this approach is ideal for scenarios where only one or two machines are available.

  • However, for deployments involving more machines, traditional Layer 4 (L4) load-balancer using servers could be utilized.

Now, let’s dive into how to use it…
First, clone the project

git clone https://github.com/patternhelloworld/docker-blue-green-runner

Step 1: Create an .env file at the root of the project.

  # Leave as it is
  HOST_IP=host.docker.internal

  # It is recommended to enter your formal URL or IP, such as https://test.com, for the 'check_availability_out_of_container' test in the 'run.sh' script.
  # Both https://your-app.com:443 and https://localhost:443 are valid
  # Docker-Blue-Runner recognizes if your App requires SSL in the Nginx router if this starts with 'https'.
  # This URL is used for the "External Integrity Check" process.
  APP_URL=https://localhost:443

  # APP_URL=http://localhost:<--!host-port-number!-->
  # PROJECT_PORT=<--!common-port-number!--> OR 
  # PROJECT_PORT=[<--!host-port-number!-->,<--!internal-project-port-number!-->]
  PROJECT_PORT=[443,8360]
  # In case USE_COMMERCIAL_SSL is 'false', the Runner generates self-signed SSL certificates. However, you should set any name for ``COMMERCIAL_SSL_NAME``.
  # In case it is 'true', locate your commercial SSLs in the folder docker-blue-green-runner/.docker/ssl. See the comments in the .env above.
  USE_COMMERCIAL_SSL=true
  # Your domain name is recommended. The files 'your-app.com.key', 'your-app.com.crt', and 'your-app.com.chained.crt' should be in place.
  COMMERCIAL_SSL_NAME=your-app.com

  DOCKER_LAYER_CORRUPTION_RECOVERY=false

  NGINX_RESTART=false
  CONSUL_RESTART=false

  # The method of acquiring Docker images:
  # build (Used in developer's local environment or during Jenkins builds when a new image needs to be built, so this module is typically used)
  # registry (Used on deployment servers where images are fetched from a repository, so this module is used)
  # If you choose the "build" method, you don't need to input the values below since Dockerfile is used (no image is fetched from the Docker registry).
  GIT_IMAGE_LOAD_FROM=build
  GIT_IMAGE_LOAD_FROM_HOST=xxx
  GIT_IMAGE_LOAD_FROM_PATHNAME=xxx
  GIT_TOKEN_IMAGE_LOAD_FROM_USERNAME=xxx
  GIT_TOKEN_IMAGE_LOAD_FROM_PASSWORD=xxx
  GIT_IMAGE_VERSION=1.0.0

  PROJECT_NAME=your-app
  ## [IMPORTANT] Ensure it matches 'PROJECT_ROOT_IN_CONTAINER' below.
  PROJECT_LOCATION=/app
  PROJECT_PORT=[443,8360]
  # Example (8093,8094,11000...)
  ADDITIONAL_PORTS=

  CONSUL_KEY_VALUE_STORE=http://consul:8500/v1/kv/deploy/your-app

  # If you locate your project on ../ (upper folder)
  HOST_ROOT_LOCATION=/var/projects/your-app
  # If you locate your project's Dockerfile ../ (upper folder)
  DOCKER_FILE_LOCATION=/var/projects/your-app

  # This is for integrating health checkers such as "https://www.baeldung.com/spring-boot-actuators"
  # This path is used for both internal and external health checks.
  # Note: Do not include a leading slash ("/") at the start of the path.
  # Example: "api/v1/health" (correct), "/api/v1/health" (incorrect)
  APP_HEALTH_CHECK_PATH=api/v1/health

  # The BAD & GOOD conditions are checked using an "AND" condition.
  # To ignore the "BAD_APP_HEALTH_CHECK_PATTERN", set it to a non-existing value (e.g., "###lsdladc").
  BAD_APP_HEALTH_CHECK_PATTERN=DOWN

  # Pattern required for a successful health check.
  GOOD_APP_HEALTH_CHECK_PATTERN=UP

  # The following trick is just for skipping the check.
  # APP_HEALTH_CHECK_PATH=login
  # BAD_APP_HEALTH_CHECK_PATTERN=xxxxxxx
  # GOOD_APP_HEALTH_CHECK_PATTERN=Head


  # This is for environment variables for docker-compose-app-${app_env}.
  DOCKER_COMPOSE_ENVIRONMENT={"TZ":"Asia/Seoul"}
  # [IMPORTANT] You can pass any variable to Step 2 of your Dockerfile using DOCKER_BUILD_ARGS, e.g., DOCKER_BUILD_ARGS={"PROJECT_ROOT_IN_CONTAINER":"/app"}."
  DOCKER_BUILD_ARGS={"PROJECT_ROOT_IN_CONTAINER":"/app"}
  # For SSL, the host folder is recommended to be './.docker/ssl' to be synchronized with 'docker-compose-nginx-original.yml'.
  # [IMPORTANT] Run mkdir -p /var/projects/files/your-app/logs on your host machine
  DOCKER_COMPOSE_SELECTIVE_VOLUMES=["/var/projects/your-app/.docker/nginx/app.conf.ctmpl:/etc/nginx-template/app.conf.ctmpl","/var/projects/files/your-app/logs:/var/log/nginx"]
  # [IMPORTANT] Run mkdir -p /var/projects/files/nginx/logs on your host machine
  DOCKER_COMPOSE_NGINX_SELECTIVE_VOLUMES=["/var/projects/files/nginx/logs:/var/log/nginx"]
  DOCKER_COMPOSE_HOST_VOLUME_CHECK=false

  NGINX_CLIENT_MAX_BODY_SIZE=50M

  USE_MY_OWN_APP_YML=false

  SKIP_BUILDING_APP_IMAGE=false

  # Docker-Swarm(stack) is currently a beta version. Use 'compose'.
  ORCHESTRATION_TYPE=compose

  ONLY_BUILDING_APP_IMAGE=false

  DOCKER_BUILD_MEMORY_USAGE=1G

  USE_NGINX_RESTRICTED_LOCATION=false
  # ex. /docs/api-app.html
  NGINX_RESTRICTED_LOCATION=xxx

  # If you set this to 'true', you won't need to configure SSL for your app. For instance, in a Spring Boot project, you won't have to create a ".jks" file. However, in rare situations, such as when it's crucial to secure all communication lines with SSL or when converting HTTPS to HTTP causes 'curl' errors, you might need to set it to 'false'.If you set this to 'true', you don't need to set SSL on your App like for example, for a Spring Boot project, you won't need to create the ".jks" file. However, in rare cases, such as ensuring all communication lines are SSL-protected, or when HTTPS to HTTP causes 'curl' errors, you might need to set it to 'false'.
  # 1) true : [Request]--> https (external network) -->Nginx--> http (internal network) --> App
  # 2) false :[Request]--> https (external network) -->Nginx--> httpS (internal network) --> App
  # !!! [IMPORTANT] As your App container below is Http, this should be set to 'true'.
  REDIRECT_HTTPS_TO_HTTP=true

  NGINX_LOGROTATE_FILE_NUMBER=7
  NGINX_LOGROTATE_FILE_SIZE=1M

  # You can change the values below. These settings for security related to ``set-safe-permissions.sh`` at the root of Docker-Blue-Green-Runner. 
  SHARED_VOLUME_GROUP_ID=1559
  SHARED_VOLUME_GROUP_NAME=mba-shared-volume-group
  UIDS_BELONGING_TO_SHARED_VOLUME_GROUP_ID=1000,1001

  USE_MY_OWN_NGINX_ORIGIN=false
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Step 2. Write your Dockerfile at the root of your project

  • React sample (SPA)

The ARG below is passed from Step 1. In SPA case, since Next.js isn’t being used, you may need to set up an additional Nginx server in your app. Spring Boot, Next.js, and NestJS each have their own servers, so no additional setup is needed for them.

FROM node:18.20.4-slim AS build

ARG PROJECT_ROOT_IN_CONTAINER

RUN mkdir -p $PROJECT_ROOT_IN_CONTAINER
COPY .. $PROJECT_ROOT_IN_CONTAINER
WORKDIR $PROJECT_ROOT_IN_CONTAINER
RUN export NODE_OPTIONS="--max-old-space-size=2048"
RUN whereis npm && alias npm='node --max_old_space_size=2048 /usr/local/bin/npm'
RUN export NODE_OPTIONS="--max-old-space-size=2048"
RUN if [ -d $PROJECT_ROOT_IN_CONTAINER/node_modules ]; then echo "[NOTICE] The node_modules folder exists. Skipping 'npm install'... "; else npm install --legacy-peer-deps; fi
RUN npm cache clean --force
RUN npm run build:prod

FROM nginx:stable

RUN apt-get update -qqy && apt-get -qqy --force-yes install curl runit wget unzip vim && \
    rm -rf /var/lib/apt/lists/* /var/cache/apt/*

ARG PROJECT_ROOT_IN_CONTAINER

COPY --chown=nginx --from=build $PROJECT_ROOT_IN_CONTAINER/dist/ $PROJECT_ROOT_IN_CONTAINER

USER root
WORKDIR $PROJECT_ROOT_IN_CONTAINER


COPY ./.docker/entrypoint.sh /entrypoint.sh
RUN chmod a+x /entrypoint.sh

ENTRYPOINT bash /entrypoint.sh
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entrypoint.sh & app.conf.ctmpl… these are not not necessary this is just my App’s setting.

entrypoint.sh, app.conf.ctmpl.. these are just for my App settings.

#!/bin/bash
cat /etc/nginx-template/app.conf.ctmpl > /etc/nginx/conf.d/default.conf
/usr/sbin/nginx -t && exec /usr/sbin/nginx -g "daemon off;"
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server {
    listen 8360; # [IMPORTANT] PROJECT_PORT in .env Step1.
    server_name localhost;

    # Root directory
    root /app; 
    index index.html
    # Access and Error logs
    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    # Gzip compression for performance improvement
    gzip on;
    gzip_comp_level 5;
    gzip_min_length 256;
    gzip_proxied any;
    gzip_vary on;

    gzip_types
        application/javascript
        application/json
        application/xml
        text/css
        text/plain;

    # Cache settings for static files for better performance
    location ~* \.(js|css|png|jpg|jpeg|gif|ico)$ {
        expires 30d;
        add_header Cache-Control "public, no-transform";
    }

    location / {
      try_files $uri $uri/ /index.html?$query_string;
    }
}
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Step 3: Deploy daily with a simple git pull && bash run.sh command

For more details, please refer to https://github.com/patternhelloworld/docker-blue-green-runner?tab=readme-ov-file#security.

Thank you for taking the time to read this!

💖 💪 🙅 🚩
andrewkangg
Andrew Kang-G

Posted on November 16, 2024

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