CLI Machines Docker Df

`ed machines docker df`

Reports docker's disk usage by object type, and how much of it is reclaimable.

ed machines docker df [--json] <machine>

Arguments

Name	Type / values	Default	What it does
`<machine>`	machine name, ssh alias, id, or any unambiguous prefix	required	Which machine to ask.

Options

Name	Type / values	Default	What it does
`--json`	flag	off	Emit JSON on stdout instead of the table.
`--help`, `-h`	flag	off	Print the help for this command on stdout and exit 0.

$ ed machines tuf docker df
TYPE           TOTAL  ACTIVE  SIZE     RECLAIMABLE
Images         12     5       11.3 GB  3.6 GB
Containers     5      0       462 MB   462 MB
Local Volumes  10     4       11.7 GB  273 MB
Build Cache    0      0       0 B      0 B

`--json` shape

[
  {
    "active": 5,
    "reclaimableBytes": 3585000000,
    "sizeBytes": 11310000000,
    "total": 12,
    "type": "Images"
  },
  {
    "active": 4,
    "reclaimableBytes": 272700000,
    "sizeBytes": 11730000000,
    "total": 10,
    "type": "Local Volumes"
  }
]

type is docker's own label: Images, Containers, Local Volumes and Build Cache, capitalised and spaced exactly like that.
total is docker's TotalCount and active is how many of them are in use.
sizeBytes and reclaimableBytes are parsed from docker's decimal strings. Docker prints reclaimable as 3.585GB (31%); the percentage is dropped and only the size is kept.

This is the report to read before pruning. reclaimableBytes for Images is what prune images would free, and the Local Volumes row is what prune volumes would free, which is data rather than cache.

Examples

ed machines tuf docker df
ed machines tuf docker df --json | jq -r '.[] | "\(.type) \(.reclaimableBytes)"'
ed machines tuf docker df --json | jq 'map(.reclaimableBytes) | add'

Behaviour notes

Read only, 45 second ceiling, docker system df --format '{{json .}}'. On a busy daemon this is the slowest of the read commands, because docker walks the image and volume trees to answer it.