A server running multiple containers with continuous/maximum uptime is of course very productive, but it is no good unless all those containers are well maintained and updated regularly.
However, the bigger question here is how do you know if there is an updated image available so that you can think of updating Docker containers?
I have already shown the steps to update docker containers with zero downtime earlier. In this tutorial, I'll tell you how to be immediately notified if any particular Docker service gets updated with a new image on Docker Hub.
Using Docker Notify to get notified of updated Docker images
Docker Notify is a freely available web service provided by Enso Origins that allows you to personalize your Docker notification updates with just your email address.
With Docker Notify, you can register yourself on their web service platform and create a list of all the Docker images you would wish to get notified about. So, whenever any particular Docker image receives a new update, you will immediately be notified via email!
Let's see how to use it.
Register yourself with Docker Notify
To use their free service, you need to sign up first. Head over to docker-notify.com and register your email:
After signing up, you will receive a new access token in your email to login. Note that this interface does not use a password-based method for both authentication and authorization. Every time you enter your email to login, you would be provided a new access token via your email alone and that would be valid for around 30 minutes.
Check your mailbox for an email from no-reply[at]enso-origins[dot]com and click on "access here" to login to the Docker Notify dashboard:
Remember to add the email address mentioned above to your known contacts list. This will ensure you always get notified directly on your primary inbox without worrying about them ending up in other folders of your mailbox.
Once that is ensured, we can start configuring our notifications. This is what you will see after clicking on "access here" from inside the email:
For now, I'm going to configure Ghost, Rocket Chat and Nextcloud.
First, I search for Ghost. You'll find other images that are present in the Docker Registry would also appear here that are either other versions or includes the same name.
Once selected, your choice will appear on the right-hand side:
Save your choice of Docker images
After confirming all your choices, please don't forget to update your changes:
On clicking on "update", you will receive a confirmation that the settings have indeed been successfully updated:
That's it! From this point onwards, you need not haunt Docker Hub every once in a while to learn whether that dockerized app received a new update or not. Ensured you have followed all the above steps correctly, you will always be notified about new updates via email!
Please also note that any time you can always unsubscribe or even delete your account if not required in the future.
Thoughts on using Docker Notify
At a personal level, Docker Notify really helped me in notifying about a recent update on Rocket Chat that was specifically released to fix a security vulnerability.
Rocket Chat does have a bot called "rocket.cat" that notifies about such news on the App. Honestly, this bot always notifies well on time but for this particular update, due to some issue, the bot did not notify me on time and I received the notification after the update was already done! So having these notifications on your email directly via Docker Notify can be very helpful!
Rocket Chat is just one app that fortunately has its own bot to notify its self-hosted instances about updates through a message on their app. But there are numerous other apps that do not have similar provisions and that is when Docker Notify becomes so resourceful!
Apart from Docker Notify, there is another Open-Source alternative to this solution with a rather exhaustive set of features which is called Diun offered by CrazyMax.
After comparing both, I found Docker Notify to be easier to use. No set-up or self-hosting configuration required here.
I have been using Docker Notify for quite a long time to manage my containers, and it helps me a lot. Even though Diun provides a host of features undoubtedly and broadly specializes in this domain, I'd still rather stick with Docker Notify because of its extremely simple, intuitive and user-friendly interface. I'm sure it wouldn't be much of a difficult task to achieve the same with Diun in the future.
I also hope that at some point, Docker Notify becomes open source as well so that anyone could self-host it as their web instance.
So in this short tutorial, we learnt about how to configure your own personalized and automated docker update notification system with Docker Notify. Hope you found it useful. Please do not hesitate if you have any thoughts, feedback or comments to share in the conversation section below.