CMD和ENTRYPOINT的区别
CMD # 指定这个容器启动的时候要运行的命令，只有最后一个会生效，可被替代
ENTRYPOINT # 指定这个容器启动的时候要运行的命令，可以追加命令
测试CMD
# 编写 dockerfile文件
[root@localhost dockerfile]# vim DockerFile-cmd
FROM centos
CMD ["ls","-a"]
# 构建镜像
[root@localhost dockerfile]# docker build -f DockerFile-cmd -t cmdtest . [root@localhost dockerfile]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE cmdtest latest 3160b7785cc7 15 seconds ago 209MB
# 运行镜像 [root@localhost dockerfile]# docker run 3160b7785cc7 . .. .dockerenv bin dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var
# 想追加一个命令 -l 即ls -al
[root@localhost dockerfile]# docker run 3160b7785cc7 -l
docker: Error response from daemon: OCI runtime create failed: container_linux.go:380: starting container process caused: exec: "-l": executable file not found in $PATH: unknown.
# cmd的情况下，-l会替代CMD ["ls","-a"]命令，-l不是命令所以报错
测试ENTRYPOINT
[root@localhost dockerfile]# vim DockerFile-ENTRYPOINT
FROM centos
ENTRYPONIT ["ls","-a"]
[root@localhost dockerfile]# docker build -f DockerFile-ENTRYPOINT -t entrypoint-test . Sending build context to Docker daemon 4.096kB Step 1/2 : FROM centos ---> 300e315adb2f Step 2/2 : ENTRYPOINT ["ls","-a"] ---> Running in 4b061853bebd Removing intermediate container 4b061853bebd ---> 6ef0aa48e5e2 Successfully built 6ef0aa48e5e2 Successfully tagged entrypoint-test:latest
[root@localhost dockerfile]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE entrypoint-test latest 6ef0aa48e5e2 11 seconds ago 209MB [root@localhost dockerfile]# docker run 6ef0aa48e5e2 . .. .dockerenv bin dev etc home lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var
# 我们的追加命令，是直接拼在我们的ENTRYPOINT命令的后面 [root@localhost dockerfile]# docker run 6ef0aa48e5e2 -l total 0 drwxr-xr-x. 1 root root 6 Aug 30 07:04 . drwxr-xr-x. 1 root root 6 Aug 30 07:04 .. -rwxr-xr-x. 1 root root 0 Aug 30 07:04 .dockerenv lrwxrwxrwx. 1 root root 7 Nov 3 2020 bin -> usr/bin drwxr-xr-x. 5 root root 340 Aug 30 07:04 dev drwxr-xr-x. 1 root root 66 Aug 30 07:04 etc drwxr-xr-x. 2 root root 6 Nov 3 2020 home lrwxrwxrwx. 1 root root 7 Nov 3 2020 lib -> usr/lib lrwxrwxrwx. 1 root root 9 Nov 3 2020 lib64 -> usr/lib64 drwx------. 2 root root 6 Dec 4 2020 lost+found drwxr-xr-x. 2 root root 6 Nov 3 2020 media drwxr-xr-x. 2 root root 6 Nov 3 2020 mnt drwxr-xr-x. 2 root root 6 Nov 3 2020 opt dr-xr-xr-x. 255 root root 0 Aug 30 07:04 proc dr-xr-x---. 2 root root 162 Dec 4 2020 root drwxr-xr-x. 11 root root 163 Dec 4 2020 run lrwxrwxrwx. 1 root root 8 Nov 3 2020 sbin -> usr/sbin drwxr-xr-x. 2 root root 6 Nov 3 2020 srv dr-xr-xr-x. 13 root root 0 Aug 24 13:01 sys drwxrwxrwt. 7 root root 145 Dec 4 2020 tmp drwxr-xr-x. 12 root root 144 Dec 4 2020 usr drwxr-xr-x. 20 root root 262 Dec 4 2020 var