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Data-only container madness

Data-only containers are a pattern for managing your docker volumes with containers instead of manually with host-mounted volumes. For more info on the pattern, see Data-only container pattern

If you are using the busybox, scratch, or <insert minimally sized image here>, you are doing it wrong, and here's why.

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Docker In-depth: Volumes

One of the most common roadblocks for people using Docker, and indeed easily the most common questions I see on on various Docker support channels, is regarding the use of volumes.

So let's take a closer look at how volumes work in Docker.

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Docker Quicktip #6: Restart Policies

Docker 1.2 introduced a powerful new feature called "restart policies". Restart policies replaces the old daemon "-r" option, which itself would try to restart all previously running containers upon daemon restart, however this was rife with trouble.

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Docker Grand Ambassador

In Docker, when you want two containers to be able to discover each other and communicate, you use links... Or at least when you first started you did and and then you gave up because links don't work well right now.

The problem with linking is that links are static. When a container which is being linked to is restarted it very likely has a new IP address. Any container which is linked to this restarted container will also need to be restarted in order to pick up this new IP address. Therefore linked containers can often have a cascading effect of needing to restart many containers in order to update links.

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DockerHub in dev-test Workflow

When DockerHub was announced there was a really handy feature added that you may have missed: Webhooks.

With DockerHub you can setup a webhook to call out to an external service once a successful push of a particular image is made (this includes completion of automated builds).

This makes for a nice addition to an existing CI/CD workflow.

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