Time Zone

When working with Docker containers, it’s crucial to set the correct timezone for your applications. Here are two straightforward methods to change the timezone in your Docker environment.

Simple Method

For a quick and easy way to set the timezone, you can use this command in your Dockerfile:

RUN ln -sf /usr/share/zoneinfo/Asia/Singapore /etc/localtime

This command creates a symbolic link to the Singapore timezone file, allowing your container to reflect the correct time without any additional packages.

Flexibility Method

Complex Method with tzdata

If you need more flexibility in changing timezones at runtime, follow these steps:

Create a Dockerfile:

# Use the latest Debian image
FROM debian:latest

# Install tzdata package
RUN apt-get update && apt-get install -y tzdata

# Set environment variable for your timezone
ENV TZ=Asia/Singapore

# Configure the timezone
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone

# Keep the container running
CMD ["tail", "-f", "/dev/null"]

Build the Image: Build your Docker image with the following command:
```
docker build -t tz-test .
```
Run the Container with CLI: You can change the timezone at runtime using the -e flag:
```
docker run --rm -it -e TZ=Asia/Tokyo tz-test date
```
This command will show the date and time in Tokyo.

Changing Timezone with Docker Compose

If you prefer using Docker Compose, you can set the timezone in your docker-compose.yml file:

services:
  tz:
    build:
      context: ./tz
    environment:
      - TZ=Asia/Singapore