docker--shell和Exec格式

shell格式

RUN apt-get install -y vim

CMD echo "docker so easy"

ENTRYPOINT echo "docker so easy"

Exec格式

RUN ["apt-get","install","-y","vim"]

CMD ["echo","docker so easy"]

ENTRYPOINT ["echo","docker so easy"]

通过两个dockerfile来对比

[root@localhost test]# cat dockerfile1/Dockerfile 
from centos
ENV name Docker
ENTRYPOINT echo "$name so easy"
[root@localhost test]# cat dockerfile2/Dockerfile 
from centos
ENV name Docker
ENTRYPOINT ["/bin/echo","$name so easy"]

[root@localhost test]# pwd
/test
[root@localhost test]# mkdir dockerfile1
[root@localhost test]# mkdir dockerfile2
[root@localhost test]# vim dockerfile1/Dockerfile
[root@localhost test]# cp dockerfile1/Dockerfile dockerfile2/
[root@localhost test]# vim dockerfile2/Dockerfile 
[root@localhost test]# cat dockerfile1/Dockerfile 
from centos
ENV name Docker
ENTRYPOINT echo "$name so easy"
[root@localhost test]# cat dockerfile2/Dockerfile 
from centos
ENV name Docker
ENTRYPOINT ["/bin/echo","$name so easy"]
[root@localhost test]# docker build -t bigni/centos_shell ./dockerfile1/
Sending build context to Docker daemon  2.048kB
Step 1/3 : from centos
 ---> 9f38484d220f
Step 2/3 : ENV name Docker
 ---> Running in 556fd0d58c0f
Removing intermediate container 556fd0d58c0f
 ---> 43e2ff86b0c7
Step 3/3 : ENTRYPOINT echo "$name so easy"
 ---> Running in d50a776a6a3a
Removing intermediate container d50a776a6a3a
 ---> fc84f5de7f3b
Successfully built fc84f5de7f3b
Successfully tagged bigni/centos_shell:latest
[root@localhost test]# docker build -t bigni/centos_exec ./dockerfile2/
Sending build context to Docker daemon  2.048kB
Step 1/3 : from centos
 ---> 9f38484d220f
Step 2/3 : ENV name Docker
 ---> Using cache
 ---> 43e2ff86b0c7
Step 3/3 : ENTRYPOINT ["/bin/echo","$name so easy"]
 ---> Running in 4c226e9e7459
Removing intermediate container 4c226e9e7459
 ---> 350ad6186f0b
Successfully built 350ad6186f0b
Successfully tagged bigni/centos_exec:latest
[root@localhost test]# docker image ls -a
REPOSITORY           TAG                 IMAGE ID            CREATED             SIZE
bigni/centos_exec    latest              350ad6186f0b        10 seconds ago      202MB
bigni/centos_shell   latest              fc84f5de7f3b        41 seconds ago      202MB
<none>               <none>              43e2ff86b0c7        42 seconds ago      202MB
bigni/centos_vim     latest              f853f2a3f901        2 hours ago         362MB
<none>               <none>              3ec8199c2855        26 hours ago        861kB
bigni/test1          latest              f5620b92331c        26 hours ago        861kB
ubuntu               14.04               2c5e00d77a67        7 weeks ago         188MB
centos               latest              9f38484d220f        3 months ago        202MB
hello-world          latest              fce289e99eb9        6 months ago        1.84kB
[root@localhost test]# docker run bigni/centos_shell
Docker so easy
[root@localhost test]# docker run bigni/centos_exec
$name so easy
[root@localhost test]# vim dockerfile2/Dockerfile 
[root@localhost test]# cat dockerfile2/Dockerfile 
from centos
ENV name Docker
ENTRYPOINT ["/bin/bash","-c","/bin/echo $name so easy"]
[root@localhost test]# docker build -t bigni/centos_exec_new ./dockerfile2/
Sending build context to Docker daemon  2.048kB
Step 1/3 : from centos
 ---> 9f38484d220f
Step 2/3 : ENV name Docker
 ---> Using cache
 ---> 43e2ff86b0c7
Step 3/3 : ENTRYPOINT ["/bin/bash","-c","/bin/echo $name so easy"]
 ---> Running in c64527904495
Removing intermediate container c64527904495
 ---> 6713eb2d0b46
Successfully built 6713eb2d0b46
Successfully tagged bigni/centos_exec_new:latest
[root@localhost test]# docker run bigni/centos_exec_new
Docker so easy
[root@localhost test]#