镜像加速：docker 镜像加速CentOS7详细介绍

$ sudo docker daemon -h
Usage: docker daemon [OPTIONS]
Enable daemon mode
 --add-registry=[]          Registry to query before a public one
 --api-cors-header=          Set CORS headers in the remote API
 -b, --bridge=            Attach containers to a network bridge
 --bip=                Specify network bridge IP
 --block-registry=[]         Don't contact given registry
 --cluster-advertise=         Address or interface name to advertise
 --cluster-store=           Set the cluster store
 --cluster-store-opt=map[]      Set cluster store options
 --confirm-def-push=true       Confirm a push to default registry
 -D, --debug=false          Enable debug mode
 --default-gateway=          Container default gateway IPv4 address
 --default-gateway-v6=        Container default gateway IPv6 address
 --default-ulimit=[]         Set default ulimits for containers
 --disable-legacy-registry=false   Do not contact legacy registries
 --dns=[]               DNS server to use
 --dns-opt=[]             DNS options to use
 --dns-search=[]           DNS search domains to use
 -e, --exec-driver=native       Exec driver to use
 --exec-opt=[]            Set exec driver options
 --exec-root=/var/run/docker     Root of the Docker execdriver
 --fixed-cidr=            IPv4 subnet for fixed IPs
 --fixed-cidr-v6=           IPv6 subnet for fixed IPs
 -G, --group=docker          Group for the unix socket
 -g, --graph=/var/lib/docker     Root of the Docker runtime
 -H, --host=[]            Daemon socket(s) to connect to
 --help=false             Print usage
 --icc=true              Enable inter-container communication
 --insecure-registry=[]        Enable insecure registry communication
 --ip=0.0.0.0             Default IP when binding container ports
 --ip-forward=true          Enable net.ipv4.ip_forward
 --ip-masq=true            Enable IP masquerading
 --iptables=true           Enable addition of iptables rules
 --ipv6=false             Enable IPv6 networking
 -l, --log-level=info         Set the logging level
 --label=[]              Set key=value labels to the daemon
 --log-driver=json-file        Default driver for container logs
 --log-opt=map[]           Set log driver options
 --mtu=0               Set the containers network MTU
 -p, --pidfile=/var/run/docker.pid  Path to use for daemon PID file
 --registry-mirror=[]         Preferred Docker registry mirror
 -s, --storage-driver=        Storage driver to use
 --selinux-enabled=false       Enable selinux support
 --storage-opt=[]           Set storage driver options
 --tls=false             Use TLS; implied by --tlsverify
 --tlscacert=~/.docker/ca.pem     Trust certs signed only by this CA
 --tlscert=~/.docker/cert.pem     Path to TLS certificate file
 --tlskey=~/.docker/key.pem      Path to TLS key file
 --tlsverify=false          Use TLS and verify the remote
 --userland-proxy=true        Use userland proxy for loopback traffic

sudo systemctl daemon-reload 
sudo service docker restart