# Docker

### connect to running container
```bash
docker exec -it <container-name> bash
```
### start stopped container. See <stopped-container-name> with docker ps -a

```bash
docker start <stopped-container-name>
```

### pytorch; standard container

```bash
docker run -it --gpus all pytorch/pytorch:latest bash
docker run -d --gpus all pytorch/pytorch:latest   # run as deamon
```
docker logs -f

### docker ipaddress or running container

docker inspect <containernameorid>| grep '"IPAddress"' | head -n 1</containernameorid>

### run iterative python program directly

docker run --rm -v $(pwd):/src --rm python:latest python /src/hello-world.py

### run iterative python shell

docker run --rm -it -v $(pwd):/src --rm python:latest python

### run bash inside python container

docker run --rm -it -v $(pwd):/src --rm python:latest /bin/bash

### run a daemon with option -d

```bash
docker run --rm --name my-postgres -e POSTGRES_PASSWORD=qw12aap -d postgres:latest
docker exec -it my-postgres   psql -h localhost -U postgres -d postgres
```

### docker files

```dockerfile
FROM python:latest
RUN pip3 install numpy
CMD python3 /src/hello-world.py
```

### docker networks

Usage: docker network COMMAND

Commands:
connect Connect a container to a network
create Create a network
disconnect Disconnect a container from a network
inspect Display detailed information on one or more networks
ls List networks
prune Remove all unused networks
rm Remove one or more networks

```bash
docker network create net_1
docker run --rm -d --net net_1 --name my_py -v $(pwd):/src  python:latest python3 /src/run.py
docker run --rm -it --net net_1 alpine:latest /bin/bash

docker network create net_2
docker run --rm --name my-postgres --network net_2 -e POSTGRES_PASSWORD=qw12aap -d postgres:latest
docker run -it --rm --name my_postgre2 --network net_2  postgres:latest /bin/bash
```

inside: psql -U postgres -h my-postgres

### Docker Compose

```docker-compose
version: '3'
services:
     python:
             image: python:latest
             container_name: my_py
             volumes:
                     - .:/src
             command: python3 /src/run.py
             restart: always
     postgres:
             image: postgres:latest
             container_name: my_post
             environment:
                     - e POSTGRES_PASSWORD=qw12aap
             restart: always
     alpine:
             image: alpine:latest
             command: echo "hello from alpine"
             restart: always
```

[How To Remove Docker Images, Containers, and Volumes](https://www.digitalocean.com/community/tutorials/how-to-remove-docker-images-containers-and-volumes)

[How to Troubleshoot “Cannot Connect to the Docker Daemon” Errors](https://www.howtogeek.com/devops/how-to-troubleshoot-cannot-connect-to-the-docker-daemon-errors/)