Docker Client Basics

Docker Client Basics

Run a bash shell in temporary Ubuntu Container and install packages

docker pull ubuntu:latest

docker run -it --rm --entrypoint=/bin/bash ubuntu:latest

apt-get update

apt-get install curl -y

exit

Run a bash shell in already started container

docker run --name ubuntu-latest -it --rm --entrypoint=/bin/bash ubuntu:latest

docker exec -it ubuntu-latest /bin/bash

Passing environment variable from host system to docker container

Passing a value as environment variable

docker run -it --rm --env MY_VALUE=123456 --entrypoint=/bin/bash ubuntu:latest

Passing an environment variable which is already defined in the host system

docker run -it --rm --env MY_VALUE --entrypoint=/bin/bash ubuntu:latest

Attach a host directory to a docker container

Using absolute path

docker run -it --rm -v /host/machine/sourcecode:/docker_container/sourcecode_directory --entrypoint=/bin/bash ubuntu:latest

Using relative path from current directory

docker run -it --rm -v `pwd`/sourcecode:/docker_container/sourcecode_directory --entrypoint=/bin/bash ubuntu:latest

ls -al

ls -al /docker_container

ls -al /docker_container/sourcecode_directory

Change the default working directory to start at the mounted volume

docker run -it --rm -v `pwd`/sourcecode:/docker_container/sourcecode_directory -w /docker_container/sourcecode_directory --entrypoint=/bin/bash ubuntu:latest

pwd

Run postgres database

Pull postgres server

docker pull postgres:latest

Start postgres server

docker run -it --rm --name postgres_latest_local -e POSTGRES_DB=mypostgresdb -e POSTGRES_USER=mypostgresuser -e POSTGRES_PASSWORD=mypostgrespassword -p 5432:5432 postgres:latest

Connect to postgres server

docker exec -it postgres_latest_local psql -h localhost -U mypostgresuser mypostgresdb

Sample query

select * from pg_catalog.pg_tables;

Define, Start, Attach and follow logs of a container

Define a Container:

docker create --name orientdb-2.0.18 -p 2424:2424 -p 2480:2480 -e ORIENTDB_ROOT_PASSWORD=rootpwd orientdb:2.0.18

Start a Container:

docker start orientdb-2.0.18

Attach to a container:

docker exec -it orientdb-2.0.18 /bin/bash

Follow logs of a container

docker logs --follow orientdb-2.0.18

Stop, Remove a Container and Remove an Image

Stop a Container:

docker stop orientdb-2.0.18

Remove a Container:

docker rm orientdb-2.0.18

Remove an image:

docker rmi orientdb-2.0.18

Check Container Logs:

docker logs -t -f  orientdb-2.0.18

List Container:

docker ps -a

List Images:

docker images

Inspect an image or running container

Inspect an image by tag:

docker inspect ubuntu:latest

Inspect an image by image id:

docker inspect <image-id>

Inspect a running container by id:

docker inspect <container-id>

Extract the config from the inspection result:

This commands highlights some key information like Cmd, Entrypoint, Environment Variable, Volumes etc

docker inspect ubuntu:latest | jq -M -r '.[].Config'

Creating tags:

Create a tag from existing tag

docker tag ubuntu:latest org.example/ubuntu:latest

Create a tag from image id

docker tag <image_id> com.example/ubuntu:latest

Clean up old/dangling volumes:

docker volume ls -qf dangling=true | xargs docker volume rm

Stop all running containers:

docker ps -q | xargs docker stop

Remove all stopped containers:

docker ps -aq | xargs docker rm 

Remove all images:

docker images -aq | xargs docker rmi -f

Monitor docker container CPU and memory usage

docker stats

Cleanup unused data from docker

Interactive mode with confirmation

docker system prune --all --volumes

Non-interactive mode

docker system prune --all --volumes --force

Get docker disk information

docker system df

Get IP address of docker container

docker inspect <container name or id> | grep -oE "\"IPAddress\"\s*:\s*\"\b([0-9]{1,3}\.){3}[0-9]{1,3}\b\""

Networking

List available networks

docker network ls

List containers attached to the network

docker network inspect <<network_name>>

Create a bridge network

docker network create --driver bridge <<network_name>>

Delete a bridge network

docker network rm <<network_name>>

Run multiple standalone containers in a network

docker run -it --rm --network <<network_name>> --name local-pg-server -p 5432:5432 -e POSTGRES_DB=local_pg_server -e POSTGRES_USER=local_user -e POSTGRES_PASSWORD=local_password postgres:11.5-alpine

docker run -it --rm --network <<network_name>> --name local-pg-cli -e PGPASSWORD=local_password postgres:11.5-alpine psql -h local-pg-server -p 5432 -d local_pg_server -U local_user