Docker Volume

Volume gerenciado pelo Docker

Volume não nomeado

Edição do arquivo compose.yaml:

~/compose$ vim compose.yaml

Arquivo compose.yaml com a inserção das linhas de volumes:

version: "3.8"

services:
  postgre:
    image: postgres:13.16
    ports:
      - 5432:5432
    environment:
      POSTGRES_PASSWORD: kubenews
      POSTGRES_USER: kubenews
      POSTGRES_DB: kubenews
    volumes:
      - postgre-docker-vol:/var/lib/postgresql/data

volumes:
  postgre-docker-vol:

Destaque para:

    volumes:
      - postgre-docker-vol:/var/lib/postgresql/data

volumes:
  postgre-docker-vol:

Derrubar o Compose Docker em execução:

~/compose$ docker compose down
WARN[0000] /home/marcelo/compose/compose.yaml: the attribute `version` is obsolete, 
it will be ignored, please remove it to avoid potential confusion
[+] Running 2/2
 ✔ Container compose-postgre-1  Removed                                       0.5s
 ✔ Network compose_default      Removed                                       0.8s

Remover o diretório do volume:

~/compose$ ls
compose.yaml  postgre-vol
~/compose$ sudo rm -rf postgre-vol/

Subir novamente o Compose Docker com os volumes especificados:

~/compose$ docker compose up -d
WARN[0000] /home/marcelo/compose/compose.yaml: the attribute `version` is obsolete, 
it will be ignored, please remove it to avoid potential confusion
[+] Running 3/3
 ✔ Network compose_default              Created                                 0.1s
 ✔ Volume "compose_postgre-docker-vol"  Created                                 0.0s
 ✔ Container compose-postgre-1          Started                                 0.3s

Lista o container e volume criado, e inspeção do container com o volume montado:

~/compose$ docker container ls
CONTAINER ID   IMAGE            COMMAND                  CREATED              STATUS              PORTS
                      NAMES
7d30f5d42acf   postgres:13.16   "docker-entrypoint.s…"   About a minute ago   Up About a minute   0.0.0.0:5432->5432/tcp, :::5432->5432/tcp   compose-postgre-1

~/compose$ docker volume ls
DRIVER    VOLUME NAME
local     compose_postgre-docker-vol

~/compose$ docker container inspect 7d30f5d42acf | grep -Ei -C 5 "volume"

        "Mounts": [
            {
                "Type": "volume",
                "Name": "compose_postgre-docker-vol",
                "Source": "/var/lib/docker/volumes/compose_postgre-docker-vol/_data",
                "Destination": "/var/lib/postgresql/data",
                "Driver": "local",
                "Mode": "z",
                "RW": true,
                "Propagation": ""
--

 "Volumes": {
                "/var/lib/postgresql/data": {}
            },

Volume nomeado

Derrubar o Compose Docker em execução

~/compose$ docker compose down
WARN[0000] /home/marcelo/compose/compose.yaml: the attribute `version` is obsolete, 
it will be ignored, please remove it to avoid potential confusion
[+] Running 2/2
 ✔ Container compose-postgre-1  Removed                                   0.5s
 ✔ Network compose_default      Removed                                   0.7s

Verificar os containers e volumes existentes:

~/compose$ docker container ls -a
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES

~/compose$ docker volume ls
DRIVER    VOLUME NAME
local     compose_postgre-docker-vol

Remover o volume existente:

~/compose$ docker volume rm compose_postgre-docker-vol

Editar o arquivo compose.yaml para inserir "name: postgre-vol":

~/compose$ vim compose.yaml

version: "3.8"

services:
  postgre:
    image: postgres:13.16
    ports:
      - 5432:5432
    environment:
      POSTGRES_PASSWORD: kubenews
      POSTGRES_USER: kubenews
      POSTGRES_DB: kubenews
    volumes:
      - postgre-docker-vol:/var/lib/postgresql/data

volumes:
  postgre-docker-vol:
    name: postgre-vol

Subida do Docker Compose:

~/compose$ docker compose up -d
WARN[0000] /home/marcelo/compose/compose.yaml: the attribute `version` is obsolete, 
it will be ignored, please remove it to avoid potential confusion
[+] Running 3/3
 ✔ Network compose_default      Created                                   0.1s
 ✔ Volume "postgre-vol"         Created                                   0.0s
 ✔ Container compose-postgre-1  Started                                   0.3s

Lista do volume criado:

$ docker volume ls
DRIVER    VOLUME NAME
local     postgre-vol

Lista e inspeção do container com o volume montado:

~/compose$ docker container ls
CONTAINER ID   IMAGE            COMMAND                  CREATED              STATUS              PORTS                                       NAMES
90b7b387d3ad   postgres:13.16   "docker-entrypoint.s…"   About a minute ago   Up About a minute   0.0.0.0:5432->5432/tcp, :::5432->5432/tcp   compose-postgre-1

~/compose$ docker container inspect 90b7b387d3ad | grep -Ei -C 5 "volume"

            "Mounts": [
                {
                    "Type": "volume",
                    "Source": "postgre-vol",
                    "Target": "/var/lib/postgresql/data",
                    "VolumeOptions": {}
                }
            ],
            
--      

              "Mounts": [
              {
                "Type": "volume",
                "Name": "postgre-vol",
                "Source": "/var/lib/docker/volumes/postgre-vol/_data",
                "Destination": "/var/lib/postgresql/data",
                "Driver": "local",
                "Mode": "z",
                "RW": true,
                "Propagation": ""    
--

            "Volumes": {
                "/var/lib/postgresql/data": {}
            },                                    

Volume externo

Derruba o Docker Compose em execução

~/compose$ docker compose down
WARN[0000] /home/marcelo/compose/compose.yaml: the attribute `version` is obsolete, 
it will be ignored, please remove it to avoid potential confusion
[+] Running 2/2
 ✔ Container compose-postgre-1  Removed                                        0.5s
 ✔ Network compose_default      Removed                                        0.7s

Lista e removo os volumes existente:

~/compose$ docker volume ls
DRIVER    VOLUME NAME
local     postgre-vol

~/compose$ docker volume rm postgre-vol
postgre-vol

Criação de volume para simular o volume externo:

~/compose$ docker volume create volume-externo
volume-externo

~/compose$ docker volume ls
DRIVER    VOLUME NAME
local     volume-externo

Edição do arquivo compose.yaml para utilizar "name: volume-externo" e "external:true":

~/compose$ vim compose.yaml

version: "3.8"

services:
  postgre:
    image: postgres:13.16
    ports:
      - 5432:5432
    environment:
      POSTGRES_PASSWORD: kubenews
      POSTGRES_USER: kubenews
      POSTGRES_DB: kubenews
    volumes:
      - postgre-docker-vol:/var/lib/postgresql/data

volumes:
  postgre-docker-vol:
    name: volume-externo
    external: true

Para "external: true" o volume deve existir, e para "external: false" o volume não pode existir. Caso contrário serão exibidos erros de "volume não encontrado" e "volume já existente", respectivamente.

Subida do Docker Compose:

~/compose$ docker compose up -d
WARN[0000] /home/marcelo/compose/compose.yaml: the attribute `version` is obsolete, 
it will be ignored, please remove it to avoid potential confusion
[+] Running 2/2
 ✔ Network compose_default      Created                                     0.1s
 ✔ Container compose-postgre-1  Started                                     0.4s

Lista e inspeção do container criado com o volume externo montado:

~/compose$ docker container ls
CONTAINER ID   IMAGE            COMMAND                  CREATED          STATUS          PORTS                                       NAMES
0975a117c23f   postgres:13.16   "docker-entrypoint.s…"   36 seconds ago   Up 35 seconds   0.0.0.0:5432->5432/tcp, :::5432->5432/tcp   compose-postgre-1

~/compose$ docker container inspect 0975a117c23f | grep -Ei -C 5 "volume"

            "Mounts": [
                {
                    "Type": "volume",
                    "Source": "volume-externo",
                    "Target": "/var/lib/postgresql/data",
                    "VolumeOptions": {}
                }
            ],
            
--  

        "Mounts": [
            {
                "Type": "volume",
                "Name": "volume-externo",
                "Source": "/var/lib/docker/volumes/volume-externo/_data",
                "Destination": "/var/lib/postgresql/data",
                "Driver": "local",
                "Mode": "z",
                "RW": true,
                "Propagation": ""   
--

            "Volumes": {
                "/var/lib/postgresql/data": {}
            },