Docker Config Reference (docker volume / docker wait)

Examples of the Docker Volume Command

The docker volume command manages Docker volumes, which are persistent storage mechanisms independent of containers. It includes subcommands for creation, listing, inspection, pruning, and removal, enabling efficient data persistence and sharing across container lifecycles. Below are 10 unique examples, each demonstrating a distinct subcommand or option combination for varied use cases.

docker volume create myvolume

This command creates a new named volume called "myvolume" using the default local driver. It allocates a dedicated storage area on the host filesystem (typically under /var/lib/docker/volumes/) that can be mounted into containers for data persistence. This volume remains independent of any container's lifecycle, ensuring data survival even after container deletion, and is ideal for initializing storage for databases or configuration files where default settings suffice.

docker volume ls

This command lists all existing volumes on the Docker host, displaying their driver type and names in a tabular format. It provides a comprehensive inventory for auditing storage resources, identifying unused volumes, or verifying the presence of specific ones before attaching them to containers, thereby supporting resource management and preventing naming conflicts.

docker volume inspect myvolume

This command inspects the specified volume "myvolume", outputting detailed metadata in JSON format, including its creation timestamp, mount point on the host, driver, labels, and scope. It enables in-depth analysis for troubleshooting mount issues or confirming configuration details, such as whether the volume is local or uses a plugin driver for remote storage.

docker volume rm myvolume

This command removes the unused volume "myvolume" from the host, deleting its associated data and freeing disk space. It requires the volume to not be in use by any containers; if referenced, the command fails to prevent data loss, making it a safe mechanism for cleanup after application decommissioning.

docker volume prune

This command removes all unused local volumes not referenced by any containers, prompting for confirmation unless forced. It scans the system for dangling volumes and reclaims storage, which is crucial for preventing disk exhaustion in environments with frequent container turnover, while preserving volumes actively in use.

docker volume create --driver local --opt type=nfs --opt o=addr=192.168.1.100 --opt device=:/nfs/share nfsvolume

This command creates a volume "nfsvolume" using the local driver with NFS options, mounting a remote NFS share from IP 192.168.1.100. It configures network-attached storage for shared access across hosts, ideal for distributed systems where data needs to be accessible from multiple nodes without relying on cloud-specific plugins.

docker volume ls --quiet

With the --quiet flag, this command lists only the names of all volumes, suppressing headers and additional details. It produces minimal output suitable for scripting, such as piping into loops for batch operations like inspections or removals, enhancing automation in CI/CD pipelines.

docker volume inspect --format '{{ .Mountpoint }}' myvolume

This command inspects "myvolume" and uses a Go template to output only its host mount point. It extracts specific attributes for programmatic use, such as in scripts verifying file paths or integrating with backup tools, providing precise control over volume metadata retrieval.

docker volume prune --force

This command forcibly prunes all unused volumes without prompting for confirmation, removing dangling storage entities. It automates aggressive cleanup in non-interactive environments like servers or containers, but requires caution to avoid accidental deletion of unreferenced but valuable data.

docker volume rm -f oldvolume1 oldvolume2

With the -f or --force flag, this command removes multiple volumes "oldvolume1" and "oldvolume2", even if they are in use by containers (after stopping references if possible). It overrides safety checks for urgent cleanups, though it risks data loss if volumes contain critical information, making it suitable for testing or disposable environments.

Examples of the Docker Wait Command

The docker wait command blocks execution until one or more specified containers stop, then outputs their exit codes. It is useful for scripting synchronization, such as waiting for a task to complete before proceeding, supporting sequential workflows in automation.

docker wait mycontainer

This command pauses the terminal until "mycontainer" stops, then prints its exit code (e.g., 0 for success). It synchronizes scripts with container completion, ideal for batch jobs where subsequent steps depend on the outcome, such as processing results after a computation finishes.

docker wait container1 container2

This command waits for both "container1" and "container2" to stop, outputting their exit codes in the order specified. It enables parallel task coordination in multi-container scenarios, ensuring all processes complete before advancing, useful in testing suites or data pipelines.

docker wait --help

This command displays the help documentation for docker wait, including usage, options, and descriptions. It provides a reference for understanding the command's behavior, such as its non-interactive nature and support for multiple arguments, aiding in proper integration into scripts.

docker wait taskcontainer > exitcode.txt

This command waits for "taskcontainer" to stop and redirects its exit code to a file "exitcode.txt". It captures outcomes for logging or conditional scripting, enabling error handling based on success (0) or failure (non-zero) in automated workflows.

docker wait longrunningjob && echo "Job completed"

This command waits for "longrunningjob" to stop and, upon success (exit code 0), executes the subsequent echo statement. It chains commands for dependent actions, such as notifications or cleanups, in shell scripts where synchronization is required without polling.