How To Update Docker Container automatically with nearly zero downtime

TL;DR

Learn how to use Watchtower, an open-source application, to automatically update Docker containers and minimize downtime during the update process.

Transcript

one question that always bothered me is how i should deal with security updates on applications that are running in docker containers so security updates are often done automatically on linux servers and that for good reasons usually this is done by the package managers that will update all installed applications but as docker containers or the app... Read More

Key Insights

• 🔐 Security updates on applications running in Docker containers can be challenging, as they are isolated from the host OS and cannot be easily updated through the package manager.
• 📺 Christian, an IT professional, shares a solution called Watchtower, an open-source application that monitors and updates Docker containers automatically.
• 🔁 Watchtower pulls down new image versions, stops the container, and recreates it with a new version when it finds an update. It can be customized to include or exclude specific containers from the update procedure.
• 📅 Scheduling updates and cleaning up old images are recommended to minimize downtime and maintain system efficiency. Watchtower allows for scheduling updates using cron expressions and can automatically delete unnecessary Docker images with the cleanup option.
• 🗄️ Watchtower can be deployed both in a Docker environment and a Portainer environment. Portainer is a web UI for managing Docker servers and can be used to set up and manage Watchtower.
• 🎥 Christian provides a detailed tutorial in the video and also offers a written blog article with all the commands and instructions in the video description.
• 💡 Watchtower provides a reliable and efficient solution for automating and managing security updates for Docker containers, ensuring the system stays up-to-date without manual intervention.
• 💬 Christian encourages viewers to join his live streams and Discord community for further support and questions, fostering a friendly and helpful community of IT professionals.

Questions & Answers

Q: How does Watchtower update Docker containers automatically?

Watchtower monitors running Docker containers and, when it finds a new image version, automatically pulls down the new image, stops the container, and recreates it with the updated version. It simplifies the update process by handling everything automatically.

Q: Can I schedule the updates of Docker containers with Watchtower?

Yes, you can schedule the updates with Watchtower. By using a cron expression, you can specify the timing and frequency of the update procedure. This allows you to plan and minimize any potential service outages during the update process.

Q: Can I exclude specific Docker containers from being updated by Watchtower?

Yes, Watchtower provides the option to exclude specific containers from the update procedure. By attaching a label to the containers, you can exclude them entirely from being watched or choose to monitor them only without updating. This gives you control over which containers are automatically updated and which ones require manual updates.

Q: What are some advanced configurations offered by Watchtower?

Watchtower offers advanced configurations such as scheduling updates at specific times using cron expressions. You can also enable the cleanup feature, which automatically deletes unnecessary Docker images that are no longer needed. These configurations enhance the control and efficiency of the update process for Docker containers.

Q: Can Watchtower be used in Portainer environments?

Yes, Watchtower can be deployed in Portainer environments. You can add a new container in Portainer and specify the scheduling, debug, and cleanup attributes as command parameters. Portainer provides a user-friendly web UI for managing your Docker server, making it easier to integrate and use Watchtower in your environment.

Summary & Key Takeaways

• Watchtower is an open-source application that monitors all running Docker containers and automatically pulls down new image versions, stops the containers, and recreates them with the updated version.

• You can schedule the updates and exclude specific containers if needed.

• Advanced configurations include scheduling updates at specific times and cleaning up old images.