docker 配置文件：/etc/docker/daemon.json

/etc/docker/daemon.json 是 docker 的配置文件，默认是没有的，需要我们手动创建，可配置项如下：

[root@localhost ~]$ vim /etc/docker/daemon.json
{
    "authorization-plugins": [],
    "data-root": "",   # 设置docker运行时的根目录
    "dns": [],         # 设置容器的DNS地址
    "dns-opts": [],    # 设置容器的/etc/resolv.conf文件
    "dns-search": [],
    "exec-opts": [],
    "exec-root": "",
    "experimental": false,
    "features": {},
    "storage-driver": "",
    "storage-opts": [],
    "labels": [],
    "live-restore": true,
    "log-driver": "json-file",
    "log-opts": {
        "max-size": "10m",
        "max-files":"5",
        "labels": "somelabel",
        "env": "os,customer"
    },
    "mtu": 0,
    "pidfile": "",    # 设置docker守护进程的PID文件
    "cluster-store": "", 
    "cluster-store-opts": {},
    "cluster-advertise": "",
    "max-concurrent-downloads": 3,
    "max-concurrent-uploads": 5,
    "default-shm-size": "64M",
    "shutdown-timeout": 15,
    "debug": true,    # 是否以debug模式启动docker
    "hosts": [],      # 设置容器的hosts
    "log-level": "",
    "tls": true,
    "tlsverify": true,
    "tlscacert": "",
    "tlscert": "",
    "tlskey": "",
    "swarm-default-advertise-addr": "",
    "api-cors-header": "",
    "selinux-enabled": false,    # 设置是否支持SELinux
    "userns-remap": "",
    "group": "",
    "cgroup-parent": "",
    "default-ulimits": {
        "nofile": {
            "Name": "nofile",
            "Hard": 64000,
            "Soft": 64000
        }
    },
    "init": false,
    "init-path": "/usr/libexec/docker-init",
    "