Olá Habr! Apresento a você a tradução do artigo "Dicas do Docker: Limpe sua máquina local", de Luc Juggery .
Hoje falaremos sobre como o Docker usa o espaço em disco da máquina host e como liberar esse espaço de imagens indesejadas de imagens e contêineres não utilizados.
Consumo total
Docker – , . , , . ( - ) Docker .
, . , , , . , , .
, Docker’, :
$ docker system df
Docker’ :
- (images) – , ;
- (containers) – , ( - );
- (local volumes) – , ;
- (build cache) – , ( BuildKit, Docker 18.09).
, (. .: , ).
/var/lib/docker , :
- /var/lib/docker/containers/ID_ – JSON-. , , , .
- /var/lib/docker/overlay2 – - (overlay2 – Linux). , .
, Docker, . :
$ docker system df
TYPE TOTAL ACTIVE SIZE RECLAIMABLE
Images 0 0 0B 0B
Containers 0 0 0B 0B
Local Volumes 0 0 0B 0B
Build Cache 0 0 0B 0B
- , , NGINX:
$ docker container run --name www -d -p 8000:80 nginx:1.16
:
- (images) 126 , NGINX, ;
- (containers) 2 .
$ docker system df
TYPE TOTAL ACTIVE SIZE RECLAIMABLE
Images 1 1 126M 0B (0%)
Containers 1 1 2B 0B (0%)
Local Volumes 0 0 0B 0B
Build Cache 0 0 0B 0B
, , . 2 , , NGINX - 100 test.img .
$ docker exec -ti www \
dd if=/dev/zero of=test.img bs=1024 count=0 seek=$[1024*100]
. , (containers) 100 .
$ docker system df
TYPE TOTAL ACTIVE SIZE RECLAIMABLE
Images 1 1 126M 0B (0%)
Containers 1 1 104.9MB 0B (0%)
Local Volumes 0 0 0B 0B
Build Cache 0 0 0B 0B
, , test.img. :
$ find /var/lib/docker -type f -name test.img
/var/lib/docker/overlay2/83f177...630078/merged/test.img
/var/lib/docker/overlay2/83f177...630078/diff/test.img
, test.img -, overlay2. , , , , :
# Stopping the www container
$ docker stop www
# Visualizing the impact on the disk usage
$ docker system df
TYPE TOTAL ACTIVE SIZE RECLAIMABLE
Images 1 1 126M 0B (0%)
Containers 1 0 104.9MB 104.9MB (100%)
Local Volumes 0 0 0B 0B
Build Cache 0 0 0B 0B
? , -.
- :
$ docker container prune
WARNING! This will remove all stopped containers.
Are you sure you want to continue? [y/N] y
Deleted Containers:
5e7f8e5097ace9ef5518ebf0c6fc2062ff024efb495f11ccc89df21ec9b4dcc2
Total reclaimed space: 104.9MB
, 104,9 . , :
$ docker system df
TYPE TOTAL ACTIVE SIZE RECLAIMABLE
Images 1 0 126M 126M (100%)
Containers 0 0 0B 0B
Local Volumes 0 0 0B 0B
Build Cache 0 0 0B 0B
: , , .
prune, , . , , :
# Historical command
$ docker rm -f $(docker ps –aq)
# More recent command
$ docker container rm -f $(docker container ls -aq)
: --rm, , .
: Ubuntu 600 , Microsoft .Net – . , . – – , , .
, :
- intermediate , – , «» ;
- dangling – intermediate , – .
- dangling :
$ docker image ls -f dangling=true
REPOSITORY TAG IMAGE ID CREATED SIZE
none none 21e658fe5351 12 minutes ago 71.3MB
:
$ docker image rm $(docker image ls -f dangling=true -q)
prune:
$ docker image prune
WARNING! This will remove all dangling images.
Are you sure you want to continue? [y/N] y
Deleted Images:
deleted: sha256:143407a3cb7efa6e95761b8cd6cea25e3f41455be6d5e7cda
deleted: sha256:738010bda9dd34896bac9bbc77b2d60addd7738ad1a95e5cc
deleted: sha256:fa4f0194a1eb829523ecf3bad04b4a7bdce089c8361e2c347
deleted: sha256:c5041938bcb46f78bf2f2a7f0a0df0eea74c4555097cc9197
deleted: sha256:5945bb6e12888cf320828e0fd00728947104da82e3eb4452f
Total reclaimed space: 12.9kB
( dangling) , :
$ docker image rm $(docker image ls -q)
(volumes) . , - , - . .
MongoDB, , ( bck.json):
# Running a mongo container
$ docker run --name db -v $PWD:/tmp -p 27017:27017 -d mongo:4.0
# Importing an existing backup (from a huge bck.json file)
$ docker exec -ti db mongoimport \
--db 'test' \
--collection 'demo' \
--file /tmp/bck.json \
--jsonArray
/var/lib/docker/volumes. - ? Dockerfile MongoDB /data/db ( MongoDB ) (volume).
: , , (volumes) .
MongoDB ( ) , . , :
$ docker volume rm $(docker volume ls -q)
prune:
$ docker volume prune
WARNING! This will remove all local volumes not used by at least one container.
Are you sure you want to continue? [y/N] y
Deleted Volumes:
d50b6402eb75d09ec17a5f57df4ed7b520c448429f70725fc5707334e5ded4d5
8f7a16e1cf117cdfddb6a38d1f4f02b18d21a485b49037e2670753fa34d115fc
599c3dd48d529b2e105eec38537cd16dac1ae6f899a123e2a62ffac6168b2f5f
...
732e610e435c24f6acae827cd340a60ce4132387cfc512452994bc0728dd66df
9a3f39cc8bd0f9ce54dea3421193f752bda4b8846841b6d36f8ee24358a85bae
045a9b534259ec6c0318cb162b7b4fca75b553d4e86fc93faafd0e7c77c79799
c6283fe9f8d2ca105d30ecaad31868410e809aba0909b3e60d68a26e92a094da
Total reclaimed space: 25.82GB
luc@saturn:~$
Docker 18.09 BuildKit. , . , , .
, Node.Js:
- index.js HTTP , :
- package.json , expressjs HTTP :
$ cat index.js
var express = require('express');
var util = require('util');
var app = express();
app.get('/', function(req, res) {
res.setHeader('Content-Type', 'text/plain');
res.end(util.format("%s - %s", new Date(), 'Got Request'));
});
app.listen(process.env.PORT || 80);
$ cat package.json
{
"name": "testnode",
"version": "0.0.1",
"main": "index.js",
"scripts": {
"start": "node index.js"
},
"dependencies": {
"express": "^4.14.0"
}
}
Dockerfile :
FROM node:13-alpine
COPY package.json /app/package.json
RUN cd /app && npm install
COPY . /app/
WORKDIR /app
EXPOSE 80
CMD ["npm", "start"]
, BuildKit:
$ docker build -t app:1.0 .
, , (node:13-alpine) (app:1.0):
TYPE TOTAL ACTIVE SIZE RECLAIMABLE
Images 2 0 109.3MB 109.3MB (100%)
Containers 0 0 0B 0B
Local Volumes 0 0 0B 0B
Build Cache 0 0 0B 0B
, BuildKit. DOCKER_BUILDKIT 1:
$ DOCKER_BUILDKIT=1 docker build -t app:2.0 .
, , (buid-cache):
$ docker system df
TYPE TOTAL ACTIVE SIZE RECLAIMABLE
Images 2 0 109.3MB 109.3MB (100%)
Containers 0 0 0B 0B
Local Volumes 0 0 0B 0B
Build Cache 11 0 8.949kB 8.949kB
:
$ docker builder prune
WARNING! This will remove all dangling build cache.
Are you sure you want to continue? [y/N] y
Deleted build cache objects:
rffq7b06h9t09xe584rn4f91e
ztexgsz949ci8mx8p5tzgdzhe
3z9jeoqbbmj3eftltawvkiayi
Total reclaimed space: 8.949kB
!
, , , . prune. docker, , :
$ docker system prune
WARNING! This will remove:
- all stopped containers
- all networks not used by at least one container
- all dangling images
- all dangling build cache
Are you sure you want to continue? [y/N]
- Docker, .