Docker

Docker is a container platform. This page covers installing Docker Engine on Ubuntu from an apt repository and configuring Docker to use a proxy.

Installation#

Add one Docker apt repository, then install the Docker packages. Run the commands below in a root shell.

Add the official apt repository#

Add Docker's official GPG key and repository:

# Add Docker's official GPG key:apt updateapt install ca-certificates curlinstall -m 0755 -d /etc/apt/keyringscurl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.ascchmod a+r /etc/apt/keyrings/docker.asc
# Add the repository to Apt sources:tee /etc/apt/sources.list.d/docker.sources <<EOFTypes: debURIs: https://download.docker.com/linux/ubuntuSuites: $(. /etc/os-release && echo "${UBUNTU_CODENAME:-$VERSION_CODENAME}")Components: stableSigned-By: /etc/apt/keyrings/docker.ascEOFapt update

Add the Alibaba Cloud public mirror repository#

To use the Alibaba Cloud public mirror, run these commands instead:

# Add Docker's official GPG key:apt updateapt install ca-certificates curlinstall -m 0755 -d /etc/apt/keyringscurl -fsSL https://mirrors.aliyun.com/docker-ce/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.ascchmod a+r /etc/apt/keyrings/docker.asc
# Add the repository to Apt sources:tee /etc/apt/sources.list.d/docker.sources <<EOFTypes: debURIs: https://mirrors.aliyun.com/docker-ce/linux/ubuntuSuites: $(. /etc/os-release && echo "${UBUNTU_CODENAME:-$VERSION_CODENAME}")Components: stableSigned-By: /etc/apt/keyrings/docker.ascEOFapt update

Add the Alibaba Cloud ECS VPC mirror repository#

On Alibaba Cloud ECS, you can use the VPC internal mirror instead:

# Add Docker's official GPG key:apt updateapt install ca-certificates curlinstall -m 0755 -d /etc/apt/keyringscurl -fsSL http://mirrors.cloud.aliyuncs.com/docker-ce/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.ascchmod a+r /etc/apt/keyrings/docker.asc
# Add the repository to Apt sources:tee /etc/apt/sources.list.d/docker.sources <<EOFTypes: debURIs: http://mirrors.cloud.aliyuncs.com/docker-ce/linux/ubuntuSuites: $(. /etc/os-release && echo "${UBUNTU_CODENAME:-$VERSION_CODENAME}")Components: stableSigned-By: /etc/apt/keyrings/docker.ascEOFapt update

Install Docker packages#

After adding a repository, install Docker Engine and its plugins:

apt install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

Configuration#

Requests such as docker pull and docker push are made by Docker Engine (dockerd), so configure the proxy on dockerd. Use any one of the methods below. They apply to Docker Engine on Linux with systemd. Docker Desktop does not use the daemon.json proxy settings described here.

Include internal domains, private registries, localhost, and 127.0.0.1 in NO_PROXY.

Configure a pull proxy in daemon.json#

Docker Engine 23.0+ supports proxy settings in daemon.json. Proxy settings in daemon.json take precedence over environment variables.

1. Add the following to /etc/docker/daemon.json:

   json

   {  "proxies": {    "http-proxy": "http://127.0.0.1:7890",    "https-proxy": "http://127.0.0.1:7890",    "no-proxy": "localhost,127.0.0.1,.local,.corp"  }}

2. Restart Docker:

   sh

   systemctl restart docker

Configure a pull proxy with systemd#

Add proxy environment variables to docker.service. If the proxy URL contains special characters such as #?!()[]{}, escape them as described in the Docker docs.

1. In a root shell, write the configuration and restart Docker:

   sh

   mkdir -p /etc/systemd/system/docker.service.dtee /etc/systemd/system/docker.service.d/http-proxy.conf <<'EOF'[Service]Environment="HTTP_PROXY=http://127.0.0.1:7890"Environment="HTTPS_PROXY=http://127.0.0.1:7890"Environment="NO_PROXY=localhost,127.0.0.1,.local,.corp"EOFsystemctl daemon-reloadsystemctl restart docker

2. Verify that the variables were loaded:

   sh

   systemctl show --property=Environment docker

Configure a pull proxy for rootless Docker#

For rootless Docker, the systemd configuration lives in the current user's directory. Run as that user:

mkdir -p ~/.config/systemd/user/docker.service.dtee ~/.config/systemd/user/docker.service.d/http-proxy.conf <<'EOF'[Service]Environment="HTTP_PROXY=http://127.0.0.1:7890"Environment="HTTPS_PROXY=http://127.0.0.1:7890"Environment="NO_PROXY=localhost,127.0.0.1,.local,.corp"EOFsystemctl --user daemon-reloadsystemctl --user restart docker

Usage#

The dockerd proxy only covers requests made by the daemon itself. For network access inside containers, or for dependencies downloaded during docker build, pass the proxy on the command line.

Run a container with a proxy#

Pass the proxy variables with -e:

docker run --rm \  -e HTTP_PROXY=http://127.0.0.1:7890 \  -e HTTPS_PROXY=http://127.0.0.1:7890 \  -e NO_PROXY=localhost,127.0.0.1,.local,.corp \  alpine env | grep -i _PROXY

Build an image with a proxy#

Pass the proxy with --build-arg. Do not put proxy settings in ENV instructions in the Dockerfile:

docker build \  --build-arg HTTP_PROXY=http://127.0.0.1:7890 \  --build-arg HTTPS_PROXY=http://127.0.0.1:7890 \  --build-arg NO_PROXY=localhost,127.0.0.1,.local,.corp \  .

Proxy URLs may contain credentials. Do not commit them to a repository.

References#

• Alibaba Cloud Container Registry console: get and configure an Alibaba Cloud registry mirror accelerator.