Images, layers, registries
On This Lesson 4 topics
This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.
In this lesson
tell an image from a container and understand layers.
Planned topics
- An image is a read-only template; a container is a running instance of it.
- Images are built from layers; unchanged layers are cached and reused.
- A registry (Docker Hub, GitHub Container Registry) stores images;
docker pulldownloads,docker pushuploads. - A tag names a version:
postgres:16. Avoidlatestbecause it changes without notice. - Verify the current supported PostgreSQL and Java base image tags before recording.
Draft outline details
Demonstration
docker pull postgres:16, docker images, and a layer diagram: base OS, JRE, app JAR.
Check your understanding
Image or container: which one runs?
Show answer
The container; the image is the template.
Practice
Apply this lesson with the module's lab, exercises and quiz.
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