Daemon proxy configuration

Table of contents

If your organization uses a proxy server to connect to the internet, you may need to configure the Docker daemon to use the proxy server. The daemon uses a proxy server to access images stored on Docker Hub and other registries, and to reach other nodes in a Docker swarm.

This page describes how to configure a proxy for the Docker daemon. For instructions on configuring proxy settings for the Docker CLI, see Configure Docker CLI to use a proxy server.

Important

Proxy configurations specified in the daemon.json are ignored by Docker Desktop. If you use Docker Desktop, you can configure proxies using the Docker Desktop settings.

There are two ways you can configure these settings:

Configuring the daemon directly takes precedence over environment variables.

Daemon configuration

You may configure proxy behavior for the daemon in the daemon.json file, or using CLI flags for the --http-proxy or --https-proxy flags for the dockerd command. Configuration using daemon.json is recommended.

{
  "proxies": {
    "http-proxy": "http://proxy.example.com:3128",
    "https-proxy": "https://proxy.example.com:3129",
    "no-proxy": "*.test.example.com,.example.org,127.0.0.0/8"
  }
}

After changing the configuration file, restart the daemon for the proxy configuration to take effect:

$ sudo systemctl restart docker

Environment variables

The Docker daemon checks the following environment variables in its start-up environment to configure HTTP or HTTPS proxy behavior:

  • HTTP_PROXY
  • http_proxy
  • HTTPS_PROXY
  • https_proxy
  • NO_PROXY
  • no_proxy

systemd unit file

If you're running the Docker daemon as a systemd service, you can create a systemd drop-in file that sets the variables for the docker service.

Note for rootless mode

The location of systemd configuration files are different when running Docker in rootless mode. When running in rootless mode, Docker is started as a user-mode systemd service, and uses files stored in each users' home directory in ~/.config/systemd/<user>/docker.service.d/. In addition, systemctl must be executed without sudo and with the --user flag. Select the "Rootless mode" tab if you are running Docker in rootless mode.

  1. Create a systemd drop-in directory for the docker service:

    $ sudo mkdir -p /etc/systemd/system/docker.service.d

  2. Create a file named /etc/systemd/system/docker.service.d/http-proxy.conf that adds the HTTP_PROXY environment variable:

    [Service]
Environment="HTTP_PROXY=http://proxy.example.com:3128"

    If you are behind an HTTPS proxy server, set the HTTPS_PROXY environment variable:

    [Service]
Environment="HTTPS_PROXY=https://proxy.example.com:3129"

    Multiple environment variables can be set; to set both a non-HTTPS and a HTTPs proxy;

    [Service]
Environment="HTTP_PROXY=http://proxy.example.com:3128"
Environment="HTTPS_PROXY=https://proxy.example.com:3129"

    Note

    Special characters in the proxy value, such as #?!()[]{}, must be double escaped using %%. For example:

    [Service]
Environment="HTTP_PROXY=http://domain%%5Cuser:complex%%23pass@proxy.example.com:3128/"

  3. If you have internal Docker registries that you need to contact without proxying, you can specify them via the NO_PROXY environment variable.

    The NO_PROXY variable specifies a string that contains comma-separated values for hosts that should be excluded from proxying. These are the options you can specify to exclude hosts:

    • IP address prefix (1.2.3.4)
    • Domain name, or a special DNS label (*)
    • A domain name matches that name and all subdomains. A domain name with a leading "." matches subdomains only. For example, given the domains foo.example.com and example.com:
      • example.com matches example.com and foo.example.com, and
      • .example.com matches only foo.example.com
    • A single asterisk (*) indicates that no proxying should be done
    • Literal port numbers are accepted by IP address prefixes (1.2.3.4:80) and domain names (foo.example.com:80)

    Example:

    [Service]
Environment="HTTP_PROXY=http://proxy.example.com:3128"
Environment="HTTPS_PROXY=https://proxy.example.com:3129"
Environment="NO_PROXY=localhost,127.0.0.1,docker-registry.example.com,.corp"

  4. Flush changes and restart Docker

    $ sudo systemctl daemon-reload
$ sudo systemctl restart docker

  5. Verify that the configuration has been loaded and matches the changes you made, for example:

    $ sudo systemctl show --property=Environment docker

Environment=HTTP_PROXY=http://proxy.example.com:3128 HTTPS_PROXY=https://proxy.example.com:3129 NO_PROXY=localhost,127.0.0.1,docker-registry.example.com,.corp

  1. Create a systemd drop-in directory for the docker service:

    $ mkdir -p ~/.config/systemd/user/docker.service.d

  2. Create a file named ~/.config/systemd/user/docker.service.d/http-proxy.conf that adds the HTTP_PROXY environment variable:

    [Service]
Environment="HTTP_PROXY=http://proxy.example.com:3128"

    If you are behind an HTTPS proxy server, set the HTTPS_PROXY environment variable:

    [Service]
Environment="HTTPS_PROXY=https://proxy.example.com:3129"

    Multiple environment variables can be set; to set both a non-HTTPS and a HTTPs proxy;

    [Service]
Environment="HTTP_PROXY=http://proxy.example.com:3128"
Environment="HTTPS_PROXY=https://proxy.example.com:3129"

    Note

    Special characters in the proxy value, such as #?!()[]{}, must be double escaped using %%. For example:

    [Service]
Environment="HTTP_PROXY=http://domain%%5Cuser:complex%%23pass@proxy.example.com:3128/"

  3. If you have internal Docker registries that you need to contact without proxying, you can specify them via the NO_PROXY environment variable.

    The NO_PROXY variable specifies a string that contains comma-separated values for hosts that should be excluded from proxying. These are the options you can specify to exclude hosts:

    • IP address prefix (1.2.3.4)
    • Domain name, or a special DNS label (*)
    • A domain name matches that name and all subdomains. A domain name with a leading "." matches subdomains only. For example, given the domains foo.example.com and example.com:
      • example.com matches example.com and foo.example.com, and
      • .example.com matches only foo.example.com
    • A single asterisk (*) indicates that no proxying should be done
    • Literal port numbers are accepted by IP address prefixes (1.2.3.4:80) and domain names (foo.example.com:80)

    Example:

    [Service]
Environment="HTTP_PROXY=http://proxy.example.com:3128"
Environment="HTTPS_PROXY=https://proxy.example.com:3129"
Environment="NO_PROXY=localhost,127.0.0.1,docker-registry.example.com,.corp"

  4. Flush changes and restart Docker

    $ systemctl --user daemon-reload
$ systemctl --user restart docker

  5. Verify that the configuration has been loaded and matches the changes you made, for example:

    $ systemctl --user show --property=Environment docker

Environment=HTTP_PROXY=http://proxy.example.com:3128 HTTPS_PROXY=https://proxy.example.com:3129 NO_PROXY=localhost,127.0.0.1,docker-registry.example.com,.corp