创建容器时添加参数 --restart=always 后，当 docker 重启时，容器自动启动。

使用方法：

docker container update --restart=always 容器名字

操作实例如下：

[root@localhost mnt]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED              STATUS              PORTS               NAMES
46cdfc60b7a6        nginx               "nginx -g 'daemon ..."   About a minute ago   Up 42 seconds       80/tcp              n3
79d55a734c26        nginx               "nginx -g 'daemon ..."   About a minute ago   Up 42 seconds       80/tcp              n2
f7b2206c019d        nginx               "nginx -g 'daemon ..."   About a minute ago   Up 46 seconds       80/tcp              n1
[root@localhost mnt]# docker container update --restart=always n1
n1
[root@localhost mnt]# systemctl restart docker 
[root@localhost mnt]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                     PORTS               NAMES
46cdfc60b7a6        nginx               "nginx -g 'daemon ..."   2 minutes ago       Exited (0) 5 seconds ago                       n3
79d55a734c26        nginx               "nginx -g 'daemon ..."   2 minutes ago       Exited (0) 5 seconds ago                       n2
f7b2206c019d        nginx               "nginx -g 'daemon ..."   2 minutes ago       Up 2 seconds               80/tcp              n1