images_and_their_layers.md (657B)
1 # images and their layers 2 # discover the image cache 3 4 * image layers 5 * union file system 6 * `history` and `inspect` commands 7 * copy on write 8 9 ## image layers 10 ``` 11 docker image history <image_name> 12 ``` 13 14 * all images start with "scratch" 15 * each layer gets a unique "sha" (sha256) 16 * don't need to download layers we already have in cache 17 * never storing multiple image layers 18 19 view image metadata 20 ``` 21 docker image inspect <image_name> 22 ``` 23 24 ## image tagging and pushing 25 * image id vs tag 26 * image don't have a "name" 27 * repository / tag / image id 28 * tag is not quite a 'version' 29 * tagging an image 30 ``` 31 docker image tag <source_image>[:tag] <target_name>[:tag] 32 ```