Docker

Create a docker image

basic instruction

Posted by Ray on May 16, 2020

Create a new image from a container’s changes

  • Usage:

    • Docker commit [OPTIONS] CONTAINER [REPOSITORY[:TAG]]

e.g: Get a busy box image and create a file inside container

1
2
3
4
5
6
7
8
9
10

docker run --name base1 -it busybox
Unable to find image 'busybox:latest' locally
latest: Pulling from library/busybox
d9cbbca60e5f: Pull complete 
Digest: sha256:836945da1f3afe2cfff376d379852bbb82e0237cb2925d53a13f53d6e8a8c48c
Status: Downloaded newer image for busybox:latest
/ #mkdir -p /data/html
vi index.html
<h1>Busybox httpd server. </h1>

In another terminal create a new image and check it

1
2
3
4
5

docker commit -p  -a "rayx1" -m "a base image with index.html" base1
docker image ls
REPOSITORY          TAG                 IMAGE ID            CREATED              SIZE
<none>              <none>              64e381aeac90        55 seconds ago       1.22MB

you will see a un-named image. To tag a image use docker tag

1
2
3

Usage:  docker tag SOURCE_IMAGE[:TAG] TARGET_IMAGE[:TAG]

Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE

e.g tag it to user rayx1 with name httpd-busybox and tag v0.1

1

docker tag 64e381aeac90 rayx1/httpd-busybox:v0.1

Also you could use multiple tags

1

docker tag rayx1/httpd-busybox:v0.1 rayx1/httpd:latest

You will see:

1
2
3

REPOSITORY            TAG                 IMAGE ID            CREATED             SIZE
rayx1/httpd-busybox   v0.1                64e381aeac90        6 minutes ago       1.22MB
rayx1/httpd           latest              64e381aeac90        6 minutes ago       1.22MB

You could remove a tag with image rm

1
2
3

docker image rm rayx1/httpd
Untagged: rayx1/httpd:latest

You can change docker file fields

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16

docker inspect base1

[
    {
        ...
        "Config": {
            ...
            "Cmd": [
                "sh"
            ],
            ...
        },
        
    }
]

Create a new image with Cmd start a httpd with version v0.2

1

docker commit -a "rayx1 <ray@myemail.com>" -c 'CMD ["/bin/httpd", "-f", "-h", "/data/html"]' -p base1 rayx1/httpd-busybox:v0.2

Run the new image

docker run : Run a command in a new container

docker run --name base2 rayx1/httpd-busybox:v0.2 Use docker inspect base2 get the ipaddress "IPAddress": "172.17.0.3", and you can check the http with lynx 172.17.0.3

start/stop/restart

docker start|stop|restart [OPTIONS] CONTAINER [CONTAINER...] Options:

1
2
3
4
5

Options:
  -a, --attach               Attach STDOUT/STDERR and forward signals
      --detach-keys string   Override the key sequence for detaching a container
  -i, --interactive          Attach container's STDIN

Note: You can not re-run a container image again. You have to start/stop/restart your container. container run only can be used for start a new container

login into docker hub and push the image

docker login -u rayx1 docker push rayx1/httpd-busybox

note you can also login into other docker image registry. e.g to login into aliyun docker docker login -u rayx1 registry.cn-beijing.aliyuncs.com and push docker push registry.cn-beijing.aliyuncs.com/rayx1/httpd-busybox:v0.2

Export and import (save/load) your local docker image (without push to server)

If you’d like to distribute your images to your teammate without push to a server (maybe, for testing purpose)

Export

docker save [OPTIONS] IMAGE [IMAGE...] e.g pack http-busybox into httpd.gz docker save -o httpd.gz rayx1/httpd-busybox:v0.2 or multiple image into a file docker save -o httpd.gz rayx1/httpd-busybox:v0.2 rayx1/busybox

import

docker load -i httpd.gz

FEATURED TAGS
Docker
FRIENDS