Upgrade Docker Image (Booksonic, m4b-tool)

Most Dockers do not update in the manner traditional to regular applications. Dockers are a full but bare bones Linux VM's, that are designed to run a specific application or server with nothing else required. Other than volumes and bind points, which are setup to allow for processing user data and for minimal configuration info to be persistent, a Docker is effectively "read only".

To update a Docker, to the latest and greatest, usually requires replacing the image and running a new container. This is what Watch Tower does and it does it well, for the most part. (There are exceptions.) However, in order for Watch Tower to update the Docker, the Docker author must publish a new Docker. This process, from the publishing of an app update until the Docker author gets around to updating the corresponding Docker, is not always timely. I've noticed that linuxserver.io is regular in providing updated Dockers, shortly after a new version of an app or server is available. On the other hand, other providers are somewhat mixed.

In any case, most application updates are about minor bug fixes that are not actually required for most users, especially where Dockers are concerned. Since Dockers are fully self contained, isolated from the host, and "read only" for the most part, there's really no need to update them unless you're looking for new features.

Since I don't use Watchtower, when I see "update available" in a Docker container, I tend to look at the app's web site to see if there's anything in the update that I'm interested in. If there's nothing new, I ignore it. In any case, I tend to ignore minor version updates and only update Dockers once or twice a year.

Quote from crashtest

Since I don't use Watchtower, when I see "update available" in a Docker container, I tend to look at the app's web site to see if there's anything in the update that I'm interested in. If there's nothing new, I ignore it. In any case, I tend to ignore minor version updates and only update Dockers once or twice a year.

Good advice. Basically, if it is not broken, don't fix it.

I read somewhere in the forums horror stories of turning Watchtower loose on your containers. I couldn't find the one I was looking for but here and here are some milder examples. It's kind of like turning your children over to a new baby sitter and then going away for a month. You should do your research, keep regular watch over your server, and keep notes so you know how to rebuild just in case Watchtower does "murder" some or all of your precious little containers.

Quote from Agricola

I read somewhere in the forums horror stories of turning Watchtower loose on your containers. I couldn't find the one I was looking for but here and here are some milder examples

As chance would have it, after answering this thread:
I gave Watchtower a trial run with updating a Pi-hole image/container, about an hour ago. It updated the image and ran a new container in eight minutes.

While environmental variables and volume mounts made it through to the new pi-hole container, custom DNS and port settings didn't cross over. Since I'm running Unbound, these settings are required. Further, the new container defaulted to Google DNS and to using non-DNSSEC servers. Had I failed to go over these settings, I wouldn't have known that there was a problem. The new pi-hole container functioned, just not the way I want it to.

Quote from Agricola

Basically, if it is not broken, don't fix it.

I'm with you here. If a Docker works and newer features are not needed, I've found it best to leave it alone.

Quote from Agricola

Basically, if it is not broken, don't fix it.

Sorry, I do not agree. If the application is just in your network - maybe, but if the application is exposed to the internet I would update.

Quote from crashtest

Docker is effectively "read only".

Again sorry, also have to disagree

Nextcloud for example can be updated from within the GUI of Nextcloud, so within the container. So r/w.

Generally, there are update instructions on hub.docker for well documented dockers. Unfortunately not for all.
linuxserver/plex for example states that the docker is updated when restarting.

For linuxserver/booksonic update instructions are given on hub.docker

https://hub.docker.com/r/linux…oksonic#application-setup

The question of docker updates has come up before using Watchtower works, where it doesn't work is Pi-Hole, this was highlighted after a user was having problems after Watchtower updated Pi-Hole.

Watchtower can be configured not to update certain containers and Pi-Hole would be a case for that, and why not update your containers, would you run OMV without updating, Windows or any other Linux distro. Most updates are for bug fixes or enhancements/improvements, whilst I champion 'if ain't broke don't fix it' I also champion 'once bitten, twice shy'

Quote from macom

Again sorry, also have to disagree
Nextcloud for example can be updated from within the GUI of Nextcloud, so within the container. So r/w.

Generally, there are update instructions on hub.docker for well documented dockers. Unfortunately not for all.
linuxserver/plex for example states that the docker is updated when restarting.

Well, as previously mentioned using the phrase;

Quote from crashtest

Most Dockers do not update in the manner traditional to regular applications.

there are notable exceptions. Nextcloud must be one of them.
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As far as Dockers being "Read Only", this is still true of a Docker image. Any change made in a container, by an update or on the command line, has no effect on the source image. If the container is respawned from the source image, for any reason, all non-persistent configuration changes (outside of mapped volumes and bind points) are gone.

Point taken. I wasn’t thinking about something like Nextcloud. I try to keep it as current as possible.

I use watchtower to maintain all my containers. I don't use Pi-hole (which I've read before will have the issues mentioned)... and I've never had a problem with it porting all info to the new image. The more annoying part about watchtower, if you don't set it up appropriately, you'll have a bunch of dead images when you get upgrades. This is easy enough to manage with either docker prune to remove them manually, or setting the --cleanup option to do so automatically.

It makes keeping your containers up to date pretty much pain free.