home/Projects/kompose/TIMEZONE_CONFIG.md

Timezone Configuration Guide

Overview

All stacks in the Kompose project can now use a centralized timezone configuration through the root .env file. The default timezone is set to Europe/Amsterdam, but can be easily changed.

Configuration

Root .env File

The timezone is configured in the root /home/valknar/Projects/kompose/.env file:

# Default timezone for all containers
# Can be overridden in individual stack .env files if needed
# Common values: Europe/Amsterdam, Europe/Berlin, America/New_York, etc.
TIMEZONE=Europe/Amsterdam

Changing the Timezone

To change the timezone for all stacks:

1. Edit the root .env file
2. Change the TIMEZONE value to your desired timezone
3. Restart the affected containers: docker compose up -d in each stack directory

Common Timezone Values

• Europe/Amsterdam
• Europe/Berlin
• Europe/London
• Europe/Paris
• America/New_York
• America/Los_Angeles
• America/Chicago
• Asia/Tokyo
• Asia/Shanghai
• Australia/Sydney

For a complete list, see: https://en.wikipedia.org/wiki/List_of_tz_database_time_zones

Adding Timezone to Stack Compose Files

Automatic Method

Use the provided Python script to automatically add timezone configuration to all compose files:

# Make script executable (first time only)
chmod +x add-timezone.py

# Run the script
./add-timezone.py

The script will:

• Find all compose.yaml files in stack subdirectories
• Add TZ: ${TIMEZONE:-Europe/Amsterdam} to each service's environment section
• Create .bak backup files before making changes
• Skip files that already have TZ configured
• Provide a summary of changes

Manual Method

If you prefer to add timezone manually or for new stacks, add the following to the environment: section of each service:

services:
  myservice:
    image: some-image
    environment:
      TZ: ${TIMEZONE:-Europe/Amsterdam}
      # ... other environment variables

The format ${TIMEZONE:-Europe/Amsterdam} means:

• Use the TIMEZONE variable from .env if it exists
• Fall back to Europe/Amsterdam if the variable is not set

Stack-Specific Timezone Override

If a specific stack needs a different timezone, you can override it in that stack's .env file:

# In /home/valknar/Projects/kompose/mystack/.env
TIMEZONE=America/New_York

Verification

To verify the timezone is correctly applied to a container:

# Check the timezone of a running container
docker exec <container_name> date

# Or check the TZ environment variable
docker exec <container_name> printenv TZ

Why Timezone Configuration Matters

Proper timezone configuration ensures:

• Log timestamps match your local time
• Scheduled tasks run at the expected times
• Database timestamps are consistent
• Application behavior matches user expectations

Troubleshooting

Container still shows wrong timezone

1. Make sure the container was restarted after adding the TZ variable:

   docker compose up -d
   

2. Check if the environment variable is properly set:

   docker compose config
   

3. Some containers may need additional configuration or volume mounts for timezone data

Changes not taking effect

1. Verify the root .env file contains the TIMEZONE variable
2. Ensure the compose file has the TZ environment variable
3. Restart the containers with docker compose up -d --force-recreate

Example: Complete Service Configuration

services:
  postgres:
    image: postgres:latest
    container_name: mystack_postgres
    restart: unless-stopped
    environment:
      TZ: ${TIMEZONE:-Europe/Amsterdam}
      POSTGRES_USER: ${DB_USER}
      POSTGRES_PASSWORD: ${DB_PASSWORD}
    volumes:
      - pgdata:/var/lib/postgresql/data
    networks:
      - kompose_network

Notes

• The timezone configuration is applied at the container level via the TZ environment variable
• This is the standard method supported by most Docker images
• Some specialized images may require different timezone configuration methods
• Always test timezone changes in a development environment first