Docker daemon 启动的时候可以有很多的命令行选项，这些选项也可以写到一个配置文件中，默认位置： /etc/docker/daemon.json ，key、value都和命令行一一对应，基本一样，但就是有些key在daemon.json中是复数形式，如： insecure-registries、storage-opts
|
1 2 3 4 5 6 |
{ "live-restore": true, "insecure-registries": ["docker-registry.i.bbtfax.com:5000"], "graph":"/data3/docker", "storage-opts":["dm.basesize=50G", "dm.loopdatasize=600G"] } |
docker-1.12 中 dm.basesize 默认10G， docker-1.9.11中默认 100G
storage-opts相关配置： https://docs.docker.com/engine/reference/commandline/dockerd/#/storage-driver-options
dm.fs 容器文件系统类型，目前支持ext4和xfs， 默认xfs
dm.loopdatasize 修改配置后，重启生效，只能改大，不能改小
dm.basesize 每次启动daemon都参考，一旦设置，无法修改，除非把daemon数据都删除重来；如果已经创建了容器了，不管该容器是死了、还是活着的、还是已删除，dm.basesize 都不能修改
有一些docker配置选项可以在不重启daemon的时候修改并生效，直接kill -HUP PID_OF_DAEMON 就可以，这种配置不多：
The list of currently supported options that can be reconfigured is this:
debug: it changes the daemon to debug mode when set to true.cluster-store: it reloads the discovery store with the new address.cluster-store-opts: it uses the new options to reload the discovery store.cluster-advertise: it modifies the address advertised after reloading.labels: it replaces the daemon labels with a new set of labels.live-restore: Enables keeping containers alive during daemon downtime.max-concurrent-downloads: it updates the max concurrent downloads for each pull.max-concurrent-uploads: it updates the max concurrent uploads for each push.default-runtime: it updates the runtime to be used if not is specified at container creation. It defaults to “default” which is the runtime shipped with the official docker packages.runtimes: it updates the list of available OCI runtimes that can be used to run containers
有些配置重启daemon都不能生效
参考： https://docs.docker.com/engine/reference/commandline/dockerd/#/configuration-reloading