docker ztd 🚀

Zero Downtime Deployment for Docker Compose

docker ztd is a CLI plugin for Docker that allows updating Docker Compose services without downtime using dynamic Traefik configurations.

Why is this important? 🤔

Updating services in production without downtime is crucial for high-load applications. Instead of using docker compose up -d <service>, which can cause downtime, docker ztd:

• Scales the service to double the number of containers ✅
• Waits for the new containers to be ready 🕐
• Removes old containers without traffic loss 🔄

📥 Installation

curl -fsSL https://gist.githubusercontent.com/ku9nov/f76d2b7f65fa266a17c89e0a50880479/raw/9182ae94d16bea270a4228dd17be16f05e156041/install-docker-ztd.sh | bash

Dependencies

You should have installed jq and yq on your server.

Depends on how Docker is installed. In some systems, you may need to create the Traefik folder manually.

mkdir -p traefik
chown -R $(id -u):$(id -g) traefik
chmod -R 755 traefik

🛠 Usage

⚠️ Your service cannot have container_name and ports defined in docker-compose.yml, as it's not possible to run multiple containers with the same name or port mapping.

Simply replace docker compose up -d <service> with docker ztd <service>.

docker ztd -f docker-compose.yml <service-name>

Or start all services:

# It is recommended to use this only once to prevent uncontrolled container recreation, for example, due to label updates. All service updates should be performed exclusively using "docker ztd <service-name>".
docker ztd -f docker-compose.yml up -d

🔧 Adding Traefik to docker-compose.yml

To ensure docker ztd works correctly, configure traefik:

services:
  traefik-proxy:
    image: traefik:v3.3.4
    command:
      - --api.insecure=true
      - --entrypoints.web.address=:80
      - --providers.file.directory=/etc/traefik # it's important to use a directory due to a Traefik bug
      - --providers.file.watch=true
    restart: unless-stopped
    ports:
      - "8000:80"
      - "8080:8080"
    volumes:
      - ./traefik:/etc/traefik:ro
    networks:
      - traefik

networks:
  traefik:
    driver: bridge

📌 Adding Traefik Labels for Services

For each service that needs to be updated without downtime, add the standard Traefik labels:

services:
  helloworld-front:
    image: <image>
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.helloworld-front.entrypoints=web" # required
      - "traefik.http.routers.helloworld-front.rule=Host(`frontend.example.com`)" # required
      - "traefik.http.services.helloworld-front.loadbalancer.server.port=80" # required

🎯 How Does It Work?

Zero Downtime Deployment is achieved through automatic generation of dynamic configurations for Traefik. By default, this file is stored at:

traefik/dynamic_conf.yml

🔗 Links

📂 Example configuration repository: docker-compose-deployments-examples

⚠️ Limitations

The docker ztd plugin does not support full configuration generation for all Traefik parameters, only a specific subset:

• traefik.enable
• traefik.http.routers.<name>.entrypoints
• traefik.http.routers.<name>.rule
• traefik.http.services.<name>.loadbalancer.server.port
• traefik.http.services.<name>.loadbalancer.healthCheck.path
• traefik.http.services.<name>.loadbalancer.healthCheck.interval
• traefik.http.services.<name>.loadbalancer.healthCheck.timeout
• traefik.http.services.<name>.loadbalancer.healthCheck.scheme
• traefik.http.services.<name>.loadbalancer.healthCheck.mode
• traefik.http.services.<name>.loadbalancer.healthCheck.hostname
• traefik.http.services.<name>.loadbalancer.healthCheck.port
• traefik.http.services.<name>.loadbalancer.healthCheck.headers.My-Custom-Header
• traefik.http.services.<name>.loadbalancer.healthCheck.followRedirects
• traefik.http.services.<name>.loadbalancer.healthCheck.method
• traefik.http.services.<name>.loadbalancer.healthCheck.status

🛣 Roadmap 🏗

• Add support for nginx-proxy 🔜
• Implement blue-green and canary deployments 🎯

🚀 Use docker ztd to update services without downtime and improve production reliability! 😎