關於「image」的入門操作

主題

• pull
• 相關設定檔
• list
• Dockerfile
• build
• run
• mount
• rm

pull

執行

podman image pull archlinux

顯示

Resolved "archlinux" as an alias (/etc/containers/registries.conf.d/shortnames.conf)
Trying to pull docker.io/library/archlinux:latest...
Getting image source signatures
Copying blob 73920abf4e07 done   |
Copying blob 74d5579544e6 done   |
Copying config eddb1ff8c1 done   |
Writing manifest to image destination
eddb1ff8c1c65c7a3bc3d3b2bf28d1ac30edc9ab525c1cdfaaa652c462db7c1e

相關設定檔

相關設定檔
/etc/containers/registries.conf
/etc/containers/registries.conf.d/shortnames.conf (Debian)

執行下面指令，觀看「/etc/containers/registries.conf」這個檔案的內容。

cat /etc/containers/registries.conf

執行下面指令，觀看「/etc/containers/registries.conf.d/shortnames.conf」這個檔案的內容。

cat /etc/containers/registries.conf.d/shortnames.conf

list

執行

podman images

或是執行

podman image list

顯示

REPOSITORY                   TAG         IMAGE ID      CREATED     SIZE
docker.io/library/archlinux  latest      eddb1ff8c1c6  2 days ago  535 MB

Dockerfile

執行下面指令，產生「into.txt」這個檔案。

echo 'test' > info.txt

執行下面指令，產生「Dockerfile」這個檔案。

cat << __EOL__ > Dockerfile
From alpine

COPY info.txt /info.txt

CMD cat /info.txt
__EOL__

相關範例
demo-create-image-from-dockerfile-001
demo-create-image-from-dockerfile-002

build

上面產生完「Dockerfile」後，接著執行下面指令，產生「image」

podman build -t demo-image .

顯示

STEP 1/3: FROM alpine
STEP 2/3: COPY info.txt /info.txt
--> da727464a881
STEP 3/3: CMD cat /info.txt
COMMIT demo-image
--> 82cceb175aed
Successfully tagged localhost/demo-image:latest
82cceb175aedf11eb5ddb0d2c8750658320d35bdae28ca9f4d308f21d78d51dd

執行

podman images

顯示

REPOSITORY                   TAG         IMAGE ID      CREATED         SIZE
localhost/demo-image         latest      82cceb175aed  29 seconds ago  8.73 MB
docker.io/library/archlinux  latest      eddb1ff8c1c6  2 days ago      535 MB
docker.io/library/debian     latest      ba695bc5c414  10 days ago     124 MB
docker.io/library/alpine     latest      e7b39c54cdec  3 weeks ago     8.74 MB

run

run image by id (82cceb175aed)

podman run 82cceb175aed

run image by name (demo-image)

podman run demo-image

run image by name (localhost/demo-image)

podman run localhost/demo-image

顯示

test

run in interactive mode

podman run -it --rm --name myarch archlinux

mount

先執行

podman unshare

接著執行下面指令，會掛載「demo-image」，掛載的路徑，會儲存到「mnt_dir_path」這個變數。

mnt_dir_path=$(podman image mount demo-image)

接著執行下面指令，就可以觀看該目錄下的內容。

ls -1 $mnt_dir_path

顯示

bin
dev
etc
home
info.txt
lib
media
mnt
opt
proc
root
run
sbin
srv
sys
tmp
usr
var

接著執行下面指令，離開。(注：因為上面執行podman unshare會進到一個新環境)

exit

相關範例
demo-copy-image-content

rm

run to remove image by id (783fdc4962b9)

podman image rm -f 82cceb175aed