19.3.4 Info CLI Command

docker info (also invokable as docker system info) displays detailed system-wide information about the Docker installation and the host machine. While docker version focuses on software versions, docker info provides operational context: resource counts, storage configuration, networking, security settings, and host hardware. It is the primary command for understanding the state and configuration of a Docker host.

Running the Command

docker info

docker system info

Both commands produce identical output.

Output Sections

The output is a long, unstructured text block covering many aspects of the Docker installation:

Client:
 Context:    default
 Debug Mode: false

Server:
 Containers: 11
  Running: 3
  Paused: 0
  Stopped: 8
 Images: 14
 Server Version: 25.0.3
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: systemd
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: runc io.containerd.runc.v2
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 7c3aca7a610df76212171d200ca3811ff6096eb8
 runc version: v1.1.12-0-g51d5e946
 init version: de40ad0
 Security Options:
  apparmor
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.1.0-21-amd64
 Operating System: Debian GNU/Linux 12 (bookworm)
 OSType: linux
 Architecture: x86_64
 CPUs: 4
 Total Memory: 7.692GiB
 Name: my-docker-host
 ID: a1b2c3d4-e5f6-7890-abcd-ef1234567890
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Username: myuser
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false

Container Counts

Containers: 11
 Running: 3
 Paused: 0
 Stopped: 8

These counts show the total number of containers on the host with a breakdown by state. This gives an immediate picture of container utilization — how many are active versus how many are stopped and potentially eligible for cleanup.

Images

Images: 14

The total number of image layers stored locally, including both tagged and untagged (dangling) images.

Storage Driver

Storage Driver: overlay2
 Backing Filesystem: extfs
 Supports d_type: true

The storage driver determines how Docker stores container filesystem layers. overlay2 is the default and recommended driver for modern Linux kernels. Other drivers include devicemapper, btrfs, zfs, and vfs.

• Backing Filesystem: The filesystem type of the Docker data root directory. extfs is ext4; xfs is also common.
• Supports d_type: Whether the filesystem supports the d_type (directory entry type) field, which is required for overlay2.

Logging Driver

Logging Driver: json-file

The default logging driver applied to all containers unless overridden at runtime. json-file writes logs to JSON files on the host. Other common options are journald, syslog, fluentd, awslogs, and none.

Cgroup Configuration

Cgroup Driver: systemd
Cgroup Version: 2

• Cgroup Driver: How Docker interacts with the Linux Control Groups subsystem. systemd delegates cgroup management to systemd; cgroupfs manages cgroups directly. Modern Linux distributions using systemd prefer the systemd driver.
• Cgroup Version: Cgroup v2 is the modern unified hierarchy. Cgroup v1 is the legacy split hierarchy. Cgroup v2 provides better resource accounting and is required for certain features like rootless Docker and memory.swap limits.

Plugins

Plugins:
 Volume: local
 Network: bridge host ipvlan macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog

Lists the installed plugins for each category. Third-party volume plugins (for cloud storage, network filesystems) appear here after installation.

Swarm Status

Swarm: inactive

Indicates whether this Docker host is participating in a Docker Swarm cluster. Values are inactive, active, or pending. If active, additional details about the node role (manager or worker), cluster ID, and manager addresses are shown.

Security Options

Security Options:
 apparmor
 seccomp
  Profile: builtin
 cgroupns

Lists the kernel security modules and isolation mechanisms active for containers:

• apparmor: AppArmor mandatory access control is active. Container processes are confined by AppArmor profiles.
• seccomp: Syscall filtering is active. The built-in Docker seccomp profile blocks calls that containers do not need.
• cgroupns: Cgroup namespace isolation is enabled, so containers see a scoped view of the cgroup hierarchy.

Host Hardware Information

Kernel Version: 6.1.0-21-amd64
Operating System: Debian GNU/Linux 12 (bookworm)
OSType: linux
Architecture: x86_64
CPUs: 4
Total Memory: 7.692GiB
Name: my-docker-host

This section is essential when diagnosing compatibility issues with certain images or when verifying that resource-constrained hosts have the necessary CPU and memory for the containers they are expected to run.

Docker Root Directory

Docker Root Dir: /var/lib/docker

The directory where Docker stores all its data: image layers, container writable layers, volumes, build cache, and network configuration. On systems with limited disk space on the root filesystem, this path can be changed in the daemon configuration.

Extracting Specific Fields

Use --format with Go templates to extract individual fields:

docker info --format "{{.DockerRootDir}}"
docker info --format "{{.Driver}}"
docker info --format "{{.Containers}}"
docker info --format "{{.MemTotal}}"
docker info --format "{{.NCPU}}"
docker info --format "{{.KernelVersion}}"
docker info --format "{{.OperatingSystem}}"

These are useful in scripts that need to check host configuration before running Docker operations.