docker container stats

内容説明	Display a live stream of container(s) resource usage statistics
利用方法	`docker container stats [OPTIONS] [CONTAINER...]`
エイリアス	`docker stats`

内容説明

The docker stats command returns a live data stream for running containers. To limit data to one or more specific containers, specify a list of container names or ids separated by a space. You can specify a stopped container but stopped containers do not return any data.

If you need more detailed information about a container's resource usage, use the /containers/(id)/stats API endpoint.

メモ
On Linux, the Docker CLI reports memory usage by subtracting cache usage from the total memory usage. The API does not perform such a calculation but rather provides the total memory usage and the amount from the cache so that clients can use the data as needed. The cache usage is defined as the value of total_inactive_file field in the memory.stat file on cgroup v1 hosts.
On Docker 19.03 and older, the cache usage was defined as the value of cache field. On cgroup v2 hosts, the cache usage is defined as the value of inactive_file field.

メモ
The PIDS column contains the number of processes and kernel threads created by that container. Threads is the term used by Linux kernel. Other equivalent terms are "lightweight process" or "kernel task", etc. A large number in the PIDS column combined with a small number of processes (as reported by ps or top) may indicate that something in the container is creating many threads.

オプション

オプション	デフォルト	内容説明
`-a, --all`		Show all containers (default shows just running)
`--format`		Format output using a custom template: 'table': Print output in table format with column headers (default) 'table TEMPLATE': Print output in table format using the given Go template 'json': Print in JSON format 'TEMPLATE': Print output using the given Go template. Refer to https://docs.docker.com/go/formatting/ for more information about formatting output with templates
`--no-stream`		Disable streaming stats and only pull the first result
`--no-trunc`		Do not truncate output

利用例

Running docker stats on all running containers against a Linux daemon.

$ docker stats

CONTAINER ID        NAME                                    CPU %               MEM USAGE / LIMIT     MEM %               NET I/O             BLOCK I/O           PIDS
b95a83497c91        awesome_brattain                        0.28%               5.629MiB / 1.952GiB   0.28%               916B / 0B           147kB / 0B          9
67b2525d8ad1        foobar                                  0.00%               1.727MiB / 1.952GiB   0.09%               2.48kB / 0B         4.11MB / 0B         2
e5c383697914        test-1951.1.kay7x1lh1twk9c0oig50sd5tr   0.00%               196KiB / 1.952GiB     0.01%               71.2kB / 0B         770kB / 0B          1
4bda148efbc0        random.1.vnc8on831idyr42slu578u3cr      0.00%               1.672MiB / 1.952GiB   0.08%               110kB / 0B          578kB / 0B          2

If you don't specify a format string using --format, the following columns are shown.

Column name	Description
`CONTAINER ID` and `Name`	the ID and name of the container
`CPU %` and `MEM %`	the percentage of the host's CPU and memory the container is using
`MEM USAGE / LIMIT`	the total memory the container is using, and the total amount of memory it is allowed to use
`NET I/O`	The amount of data the container has received and sent over its network interface
`BLOCK I/O`	The amount of data the container has written to and read from block devices on the host
`PIDs`	the number of processes or threads the container has created

Running docker stats on multiple containers by name and id against a Linux daemon.

$ docker stats awesome_brattain 67b2525d8ad1

CONTAINER ID        NAME                CPU %               MEM USAGE / LIMIT     MEM %               NET I/O             BLOCK I/O           PIDS
b95a83497c91        awesome_brattain    0.28%               5.629MiB / 1.952GiB   0.28%               916B / 0B           147kB / 0B          9
67b2525d8ad1        foobar              0.00%               1.727MiB / 1.952GiB   0.09%               2.48kB / 0B         4.11MB / 0B         2

Running docker stats on container with name nginx and getting output in json format.

$ docker stats nginx --no-stream --format "{{ json . }}"
{"BlockIO":"0B / 13.3kB","CPUPerc":"0.03%","Container":"nginx","ID":"ed37317fbf42","MemPerc":"0.24%","MemUsage":"2.352MiB / 982.5MiB","Name":"nginx","NetIO":"539kB / 606kB","PIDs":"2"}

Running docker stats with customized format on all (running and stopped) containers.

$ docker stats --all --format "table {{.Container}}\t{{.CPUPerc}}\t{{.MemUsage}}" fervent_panini 5acfcb1b4fd1 humble_visvesvaraya big_heisenberg

CONTAINER                CPU %               MEM USAGE / LIMIT
fervent_panini           0.00%               56KiB / 15.57GiB
5acfcb1b4fd1             0.07%               32.86MiB / 15.57GiB
humble_visvesvaraya      0.00%               0B / 0B
big_heisenberg           0.00%               0B / 0B

humble_visvesvaraya and big_heisenberg are stopped containers in the above example.

Running docker stats on all running containers against a Windows daemon.

PS E:\> docker stats
CONTAINER ID        CPU %               PRIV WORKING SET    NET I/O             BLOCK I/O
09d3bb5b1604        6.61%               38.21 MiB           17.1 kB / 7.73 kB   10.7 MB / 3.57 MB
9db7aa4d986d        9.19%               38.26 MiB           15.2 kB / 7.65 kB   10.6 MB / 3.3 MB
3f214c61ad1d        0.00%               28.64 MiB           64 kB / 6.84 kB     4.42 MB / 6.93 MB

Running docker stats on multiple containers by name and id against a Windows daemon.

PS E:\> docker ps -a
CONTAINER ID        NAME                IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
3f214c61ad1d        awesome_brattain    nanoserver          "cmd"               2 minutes ago       Up 2 minutes                            big_minsky
9db7aa4d986d        mad_wilson          windowsservercore   "cmd"               2 minutes ago       Up 2 minutes                            mad_wilson
09d3bb5b1604        fervent_panini      windowsservercore   "cmd"               2 minutes ago       Up 2 minutes                            affectionate_easley

PS E:\> docker stats 3f214c61ad1d mad_wilson
CONTAINER ID        NAME                CPU %               PRIV WORKING SET    NET I/O             BLOCK I/O
3f214c61ad1d        awesome_brattain    0.00%               46.25 MiB           76.3 kB / 7.92 kB   10.3 MB / 14.7 MB
9db7aa4d986d        mad_wilson          9.59%               40.09 MiB           27.6 kB / 8.81 kB   17 MB / 20.1 MB

Format the output (--format)

The formatting option (--format) pretty prints container output using a Go template.

Valid placeholders for the Go template are listed below:

Placeholder	Description
`.Container`	Container name or ID (user input)
`.Name`	Container name
`.ID`	Container ID
`.CPUPerc`	CPU percentage
`.MemUsage`	Memory usage
`.NetIO`	Network IO
`.BlockIO`	Block IO
`.MemPerc`	Memory percentage (Not available on Windows)
`.PIDs`	Number of PIDs (Not available on Windows)

When using the --format option, the stats command either outputs the data exactly as the template declares or, when using the table directive, includes column headers as well.

The following example uses a template without headers and outputs the Container and CPUPerc entries separated by a colon (:) for all images:

$ docker stats --format "{{.Container}}: {{.CPUPerc}}"

09d3bb5b1604: 6.61%
9db7aa4d986d: 9.19%
3f214c61ad1d: 0.00%

To list all containers statistics with their name, CPU percentage and memory usage in a table format you can use:

$ docker stats --format "table {{.Container}}\t{{.CPUPerc}}\t{{.MemUsage}}"

CONTAINER           CPU %               PRIV WORKING SET
1285939c1fd3        0.07%               796 KiB / 64 MiB
9c76f7834ae2        0.07%               2.746 MiB / 64 MiB
d1ea048f04e4        0.03%               4.583 MiB / 64 MiB

The default format is as follows:

On Linux:

"table {{.ID}}\t{{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.MemPerc}}\t{{.NetIO}}\t{{.BlockIO}}\t{{.PIDs}}"

On Windows:

"table {{.ID}}\t{{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.NetIO}}\t{{.BlockIO}}"