oracular (8) dockerd.8.gz

Provided by: docker.io_26.1.3-0ubuntu1.1_amd64 bug

NAME

       dockerd - Enable daemon mode

SYNOPSIS

       dockerd   [--add-runtime[=[]]]  [--allow-nondistributable-artifacts[=[]]]  [--api-cors-header=[=API-CORS-
       HEADER]]  [--authorization-plugin[=[]]]   [-b|--bridge[=BRIDGE]]   [--bip[=BIP]]   [--cgroup-parent[=[]]]
       [--config-file[=path]]    [--containerd[=SOCKET-PATH]]    [--data-root[=/var/lib/docker]]    [-D|--debug]
       [--default-cgroupns-mode[=host]]  [--default-gateway[=DEFAULT-GATEWAY]]   [--default-gateway-v6[=DEFAULT-
       GATEWAY-V6]]  [--default-address-pool[=DEFAULT-ADDRESS-POOL]]  [--default-network-opt[=DRIVER=OPT=VALUE]]
       [--default-runtime[=runc]] [--default-ipc-mode=MODE] [--default-shm-size[=64MiB]] [--default-ulimit[=[]]]
       [--dns[=[]]]   [--dns-opt[=[]]]   [--dns-search[=[]]]  [--exec-opt[=[]]]  [--exec-root[=/var/run/docker]]
       [--experimental[=false]]          [--fixed-cidr[=FIXED-CIDR]]           [--fixed-cidr-v6[=FIXED-CIDR-V6]]
       [-G|--group[=docker]]  [-H|--host[=[]]]  [--help]  [--http-proxy[""]]  [--https-proxy[""]] [--icc[=true]]
       [--init[=false]]  [--init-path[=""]]  [--insecure-registry[=[]]]  [--ip[=0.0.0.0]]  [--ip-forward[=true]]
       [--ip-masq[=true]]    [--iptables[=true]]    [--ipv6]   [--isolation[=default]]   [-l|--log-level[=info]]
       [--label[=[]]]  [--live-restore[=false]]   [--log-driver[=json-file]]   [--log-opt[=map[]]]   [--mtu[=0]]
       [--max-concurrent-downloads[=3]]   [--max-concurrent-uploads[=5]]   [--max-download-attempts[=5]]  [--no-
       proxy[""]] [--node-generic-resources[=[]]] [-p|--pidfile[=/var/run/docker.pid]] [--raw-logs] [--registry-
       mirror[=[]]]       [-s|--storage-driver[=STORAGE-DRIVER]]      [--seccomp-profile[=SECCOMP-PROFILE-PATH]]
       [--selinux-enabled]    [--shutdown-timeout[=15]]     [--storage-opt[=[]]]     [--swarm-default-advertise-
       addr[=IP|INTERFACE]]     [--tls]     [--tlscacert[=~/.docker/ca.pem]]    [--tlscert[=~/.docker/cert.pem]]
       [--tlskey[=~/.docker/key.pem]]   [--tlsverify]   [--userland-proxy[=true]]   [--userland-proxy-path[=""]]
       [--userns-remap[=default]] [--validate]

DESCRIPTION

       dockerd  is used for starting the Docker daemon (i.e., to command the daemon to manage images, containers
       etc).  So dockerd is a server, as a daemon.

       To run the Docker daemon you can specify dockerd.  You can check the daemon options using dockerd --help.
       Daemon options should be specified after the dockerd keyword in the following format.

       dockerd [OPTIONS]

OPTIONS

       --add-runtime=[]
         Runtimes can be registered with the daemon either via the configuration file or using the --add-runtime
       command line argument.

       The following is an example adding 2 runtimes via the configuration:

       {
            "default-runtime": "runc",
            "runtimes": {
                 "runc": {
                      "path": "runc"
                 },
                 "custom": {
                      "path": "/usr/local/bin/my-runc-replacement",
                      "runtimeArgs": [
                           "--debug"
                      ]
                 }
            }
       }

       This is the same example via the command line:

       $ sudo dockerd --add-runtime runc=runc --add-runtime custom=/usr/local/bin/my-runc-replacement

       Note: defining runtime arguments via the command line is not supported.

       --allow-nondistributable-artifacts=[]
         Push nondistributable artifacts to the specified registries.

       List can contain elements with CIDR notation to specify a whole subnet.

       This option is useful when pushing images containing nondistributable
         artifacts to a registry on an air-gapped network so hosts on that network can
         pull the images without connecting to another server.

       Warning: Nondistributable artifacts typically have restrictions on how
         and where they can be distributed and shared. Only use this feature to push
         artifacts to private registries and ensure that you are in compliance with
         any terms that cover redistributing nondistributable artifacts.

       --api-cors-header=""
         Set CORS headers in the Engine API. Default is cors disabled. Give urls like
         "http://foo, http://bar, ...". Give "*" to allow all.

       --authorization-plugin=""
         Set authorization plugins to load

       -b, --bridge=""
         Attach containers to a pre-existing network bridge; use 'none' to disable
         container networking

       --bip=""
         Use the provided CIDR notation address for the dynamically created bridge
         (docker0); Mutually exclusive of -b

       --cgroup-parent=""
         Set parent cgroup for all containers. Default is "/docker" for fs cgroup
         driver and "system.slice" for systemd cgroup driver.

       --config-file="/etc/docker/daemon.json"
         Specifies the JSON file path to load the configuration from. Default is
         /etc/docker/daemon.json.

       --containerd=""
         Path to containerd socket.

       --data-root=""
         Path to the directory used to store persisted Docker data such as
         configuration for resources, swarm cluster state, and filesystem data for
         images, containers, and local volumes. Default is /var/lib/docker.

       -D, --debug=true|false
         Enable debug mode. Default is false.

       --default-cgroupns-mode="host|private"
         Set the default cgroup namespace mode for newly created containers. The argument
         can either be host or private. If unset, this defaults to host on cgroup v1,
         or private on cgroup v2.

       --default-gateway=""
         IPv4 address of the container default gateway; this address must be part of
         the bridge subnet (which is defined by -b or --bip)

       --default-gateway-v6=""
         IPv6 address of the container default gateway

       --default-address-pool=""
         Default address pool from which IPAM driver selects a subnet for the networks.
         Example: base=172.30.0.0/16,size=24 will set the default
         address pools for the selected scope networks to {172.30.[0-255].0/24}

       --default-network-opt=DRIVER=OPT=VALUE
         Default network driver options

       --default-runtime="runtime"
         Set default runtime if there're more than one specified by --add-runtime.

       --default-ipc-mode="private|shareable"
         Set the default IPC mode for newly created containers. The argument
         can either be private or shareable.

       --default-shm-size=size
         Set the daemon-wide default shm size for containers. Default is 64MiB.

       --default-ulimit=[]
         Default ulimits for containers.

       --dns=""
         Force Docker to use specific DNS servers.

       --dns-opt=""
         DNS options to use.

       --dns-search=[]
         DNS search domains to use.

       --exec-opt=[]
         Set runtime execution options. See RUNTIME EXECUTION OPTIONS.

       --exec-root=""
         Path to use as the root of the Docker execution state files. Default is
         /var/run/docker.

       --experimental=""
         Enable the daemon experimental features.

       --fixed-cidr=""
         IPv4 subnet for fixed IPs (e.g., 10.20.0.0/16); this subnet must be nested in
         the bridge subnet (which is defined by -b or --bip).

       --fixed-cidr-v6=""
         IPv6 subnet for global IPv6 addresses (e.g., 2a00:1450::/64)

       -G, --group=""
         Group to assign the unix socket specified by -H when running in daemon mode.
         use '' (the empty string) to disable setting of a group. Default is docker.

       -H, --host=[unix:///var/run/docker.sock]: tcp://[host:port] to bind or unix://[/path/to/socket] to use.
         The socket(s) to bind to in daemon mode specified using one or more
         tcp://host:port, unix:///path/to/socket, fd://* or fd://socketfd.

       --help
         Print usage statement

       --http-proxy""
         Proxy URL for HTTP requests unless overridden by NoProxy.

       --https-proxy""
         Proxy URL for HTTPS requests unless overridden by NoProxy.

       --icc=true|false
         Allow unrestricted inter-container and Docker daemon host communication. If
         disabled, containers can still be linked together using the --link option
         (see docker-run(1)). Default is true.

       --init
         Run an init process inside containers for signal forwarding and process
         reaping.

       --init-path
         Path to the docker-init binary.

       --insecure-registry=[]
         Enable insecure registry communication, i.e., enable un-encrypted and/or
         untrusted communication.

       List of insecure registries can contain an element with CIDR notation to
         specify a whole subnet. Insecure registries accept HTTP and/or accept HTTPS
         with certificates from unknown CAs.

       Enabling --insecure-registry is useful when running a local registry.
         However, because its use creates security vulnerabilities it should ONLY be
         enabled for testing purposes.  For increased security, users should add their
         CA to their system's list of trusted CAs instead of using
         --insecure-registry.

       --ip=""
         Default IP address to use when binding container ports. Default is 0.0.0.0.

       --ip-forward=true|false
         Enables IP forwarding on the Docker host. The default is true. This flag
         interacts with the IP forwarding setting on your host system's kernel. If
         your system has IP forwarding disabled, this setting enables it. If your
         system has IP forwarding enabled, setting this flag to false
         has no effect.

       This setting will also enable IPv6 forwarding if you have both
         --ip-forward=true and --fixed-cidr-v6 set. Note that this may reject
         Router Advertisements and interfere with the host's existing IPv6
         configuration. For more information, please consult the documentation about
         "Advanced Networking - IPv6".

       --ip-masq=true|false
         Enable IP masquerading for bridge's IP range. Default is true.

       --iptables=true|false
         Enable Docker's addition of iptables rules. Default is true.

       --ipv6=true|false
         Enable IPv6 support. Default is false. Docker will create an IPv6-enabled
         bridge with address fe80::1 which will allow you to create IPv6-enabled
         containers. Use together with --fixed-cidr-v6 to provide globally routable
         IPv6 addresses. IPv6 forwarding will be enabled if not used with
         --ip-forward=false. This may collide with your host's current IPv6
         settings. For more information please consult the documentation about
         "Advanced Networking - IPv6".

       --isolation="default"
          Isolation specifies the type of isolation technology used by containers.
          Note that the default on Windows server is process, and the default on
          Windows client is hyperv. Linux only supports default.

       -l, --log-level="debug|info|warn|error|fatal"
         Set the logging level. Default is info.

       --label="[]"
         Set key=value labels to the daemon (displayed in docker info)

       --live-restore=false
         Enable live restore of running containers when the daemon starts so that they
         are not restarted. This option is applicable only for docker daemon running
         on Linux host.

       --log-driver="json-file|syslog|journald|gelf|fluentd|awslogs|splunk|etwlogs|gcplogs|none"
         Default driver for container logs. Default is json-file.
         Warning: docker logs command works only for json-file logging driver.

       --log-opt=[]
         Logging driver specific options.

       --mtu=0
         Set the containers network mtu. Default is 0.

       --max-concurrent-downloads=3
         Set the max concurrent downloads. Default is 3.

       --max-concurrent-uploads=5
         Set the max concurrent uploads. Default is 5.

       --max-download-attempts=5
         Set the max download attempts for each pull. Default is 5.

       --no-proxy="""
         Comma-separated values specifying hosts that should be excluded from proxying.

       --node-generic-resources=[]
         Advertise user-defined resource. Default is [].
         Use this if your swarm cluster has some nodes with custom
         resources (e.g: NVIDIA GPU, SSD, ...) and you need your services to land on
         nodes advertising these resources.
         Usage example: --node-generic-resources "NVIDIA-GPU=UUID1"
         --node-generic-resources "NVIDIA-GPU=UUID2"

       -p, --pidfile="path"
         Path to use for daemon PID file. Default is /var/run/docker.pid.

       --raw-logs
         Output daemon logs in full timestamp format without ANSI coloring. If this
         flag is not set, the daemon outputs condensed, colorized logs if a terminal
         is detected, or full ("raw") output otherwise.

       --registry-mirror=://
         Prepend a registry mirror to be used for image pulls. May be specified
         multiple times.

       -s, --storage-driver=""
         Force the Docker runtime to use a specific storage driver.

       --seccomp-profile=""
         Path to seccomp profile.

       --selinux-enabled=true|false
         Enable selinux support. Default is false.

       --shutdown-timeout=seconds
         Set the shutdown timeout value in seconds. Default is 15.

       --storage-opt=[]
         Set storage driver options. See STORAGE DRIVER OPTIONS.

       --swarm-default-advertise-addr=IP|INTERFACE
         Set default address or interface for swarm to advertise as its
         externally-reachable address to other cluster members. This can be a
         hostname, an IP address, or an interface such as eth0. A port cannot be
         specified with this option.

       --tls=true|false
         Use TLS; implied by --tlsverify. Default is false.

       --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=true|false
         Use TLS and verify the remote (daemon: verify client, client: verify daemon).
         Default is false.

       --userland-proxy=true|false
         Rely on a userland proxy implementation for inter-container and
         outside-to-container loopback communications. Default is true.

       --userland-proxy-path=""
         Path to the userland proxy binary.

       --userns-remap=default|uid:gid|user:group|user|uid
         Enable user namespaces for containers on the daemon. Specifying "default"
         will cause a new user and group to be created to handle UID and GID range
         remapping for the user namespace mappings used for contained processes.
         Specifying a user (or uid) and optionally a group (or gid) will cause the
         daemon to lookup the user and group's subordinate ID ranges for use as the
         user namespace mappings for contained processes.

       --validate
         Validate daemon configuration and exit.

STORAGE DRIVER OPTIONS

       Docker uses storage backends (known as "storage drivers" in the  Docker  internals)  to  create  writable
       containers  from  images.   Many  of  these  backends  use operating system level technologies and can be
       configured.

       Specify options to the storage backend with --storage-opt flags. The backends that currently take options
       are zfs and btrfs.  Options for zfs start with zfs., and options for btrfs start with btrfs..

ZFS options

   zfs.fsname
       Set  zfs  filesystem under which docker will create its own datasets.  By default docker will pick up the
       zfs filesystem where docker graph (/var/lib/docker) is located.

       Example use: dockerd -s zfs --storage-opt zfs.fsname=zroot/docker

Btrfs options

   btrfs.min_space
       Specifies the minimum size to use when creating the subvolume which is used for containers. If user  uses
       disk  quota  for btrfs when creating or running a container with --storage-opt size option, docker should
       ensure the size cannot be smaller than btrfs.min_space.

       Example use: docker daemon -s btrfs --storage-opt btrfs.min_space=10G

Access authorization

       Docker's access authorization can be  extended  by  authorization  plugins  that  your  organization  can
       purchase or build themselves. You can install one or more authorization plugins when you start the Docker
       daemon using the --authorization-plugin=PLUGIN_ID option.

       dockerd --authorization-plugin=plugin1 --authorization-plugin=plugin2,...

       The PLUGIN_ID value is either the plugin's name or  a  path  to  its  specification  file.  The  plugin's
       implementation  determines whether you can specify a name or path. Consult with your Docker administrator
       to get information about the plugins available to you.

       Once a plugin is installed, requests made to the daemon through the command line or Docker's  Engine  API
       are allowed or denied by the plugin.  If you have multiple plugins installed, each plugin, in order, must
       allow the request for it to complete.

       For  information  about  how  to  create  an  authorization  plugin,  see  access  authorization   plugin
       ⟨https://docs.docker.com/engine/extend/plugins_authorization/⟩  section  in  the Docker extend section of
       this documentation.

RUNTIME EXECUTION OPTIONS

       You can configure the runtime using options specified with the --exec-opt flag.  All the  flag's  options
       have the native prefix. A single native.cgroupdriver option is available.

       The  native.cgroupdriver option specifies the management of the container's cgroups. You can only specify
       cgroupfs or systemd. If you specify systemd and it is not available, the system errors out. If  you  omit
       the  native.cgroupdriver  option,cgroupfs  is used on cgroup v1 hosts, systemd is used on cgroup v2 hosts
       with systemd available.

       This example sets the cgroupdriver to systemd:

       $ sudo dockerd --exec-opt native.cgroupdriver=systemd

       Setting this option applies to all containers the daemon launches.

HISTORY

       Sept     2015,     Originally     compiled     by     Shishir     Mahajan      shishir.mahajan@redhat.commailto:shishir.mahajan@redhat.com⟩ based on docker.com source material and internal work.