Docker Container

Show help

docker help <command>

Show processes in container

docker top <container>

Execute command in container

docker exec -it<container_name> <command>

Example

docker exec -it my_xenial /bin/bash

Download of Docker container

docker pull <image_name>:<version>

Start Docker Container

docker run [<options>] <image_name>[:<tag>] '[<command>] [<args>...]

Example

docker run hello-world

Start interactive

docker run -i -t ubuntu /bin/bash

Starts ubuntu container in interactive mode, prompt in terminal

Detached start (Background)

docker run --name hello_docker -d skimpytoo/hello-docker

Set environmentvariables

Docker run -e VARIABLE1=VAL1 -e VARIABLE2=VAL2

Start explicit version

docker run <image_name>:<version-tag>

Example

docker run ubuntu:xenial
docker pull ubuntu:xenial

Port forwarding

docker run –name <name> -d -p 8080:80 <image_name>

ContainerPort 80-> Port on outside 8080

Example

 docker run --name test-nginx -d -p 8080:80 nginx

Remove Container after exit

docker run --name hello_docker -d -rm skimpytoo/hello-docker

Mount Volume

--v | --volume [<VOLUME_NAME >]:<mount_path>[:<options>]
or
--mount <key>=<value> [,<key>=<value> [,…]]

Example

docker run -i -t --name=voltest --mount source=test-vol,target=/test_data ubuntu /bin/bash
docker run -i -t --name=voltest2 -v test-vol:/test_data ubuntu /bin/bash

Use defined network

docker container run -d --name nginx --network test_net nginx

List containers

docker container ls [<optionen>]

Examples

docker container ls     List all running containers
docker container ls -all  List running and stopped containers

Connect terminal with container

docker container attach [<OPTIONEN>] <CONTAINER>

Stop container

docker stop <container_name>

Example

docker stop hello-docker

Restart container

docker restart <container_name>

Kill container

docker kill [<optionen>] <container> [<container> …]

Example

docker kill hello-docker

Remove container

docker container rm <container_name>

Example

docker container rm hello-docker

List running container

docker container ls

Images

Download images

docker image pull <image_name>:<version>

List downloaded images

docker image ls

Search image

docker search <image name>

Example

docker search hello-world

Create own images

docker build -t skimpytoo/hello-docker .

DockerFile:
FROM ubuntu:latest
CMD [“/bin/bash”]

Publish in dockerhub

Login

docker login

Push to dockerhub

docker push [OPTIONS] NAME[:TAG]

Examples

docker push <DOCKER_ID>/hello-docker

Volumes

Create volume

docker volume create <volume_name>

List volumes

docker volume ls

Get detailinformationen

docker volume inspect <volume_name>

Volume löschen

docker volume rm <volume_name>

Logs

Show logs

docker logs <container_name>

Options

-f, --follow      Add new incoming loglines
--tail <number>   Number of loglines
--details         Additional information
--timestamp, -t   With timestamp

Change log driver

docker run --name example_app --log-driver none -d -p 8808:80 test/example-app

Persist log entries

docker run --name example_app -d -p 8808:80 -v volumename:/var/log test/example-app

Network

List networks

docker network ls

Standard: none, host, bridge
‚overlay‘ Network that can connect multiple networks
```cmd

## Network details
```cmd
Docker network inspect <network>

Show networks

docker network create [<OPTIONEN>] <NAME>

Examples

docker network create –d bridge test_net

Neues Netzwerk, basierend auf bridge

Connect container with network

docker network connect [<OPTIONEN>] <NETZWERK> <CONTAINER>

Example

docker network connect demo_net nginx

RemoveContainer von Netzwerk trennen

docker network disconnect [<OPTIONS>] <NETZWERK> <CONTAINER>

Example

docker network disconnect test_net nginx

Docker Compose

Searches per default for

• ./docker-compose.yml
• ./docker-compose.yaml

Start

docker-compose up -d

Stop

docker-compose down

Logs

docker-compose logs

Prints the logs of all containers

Scale

docker-compose up --scale redis-master=3 –d

or inside docker-compose.yml
scale: 3 Unter Service

Environmentvariables

Searches by default in

.env

You can use the variables in docker-compose.yaml like

${VARIABLEN_NAME}

Example

.env:
NGINX_VERSION=1.17.7
docker-compose.yaml:
services:
my_web:
image: "nginx:${NGINX_VERSION}"

Defaultvalues

: after variablename defines the default

Example

image: "nginx:${NGINX_VERSION:-latest}"  – latest, if variable is not set, or empty
image: "nginx:${NGINX_VERSION-latest}" - latest, if variable not set
image: "nginx:${NGINX_VERSION:latest}" - latest, if variable empty

Define environment variable in container

Environment-section in service
services:
ubuntu_ext:
…
environment:

- DATABASE=my_db or DATABASE: my_db
- BRANCH=develop

To use variables from .env, just use the name

environment:

- DATABASE
- BRANCH

Dependent Container

In docker-compose.yml

services:
database:
…
wordpress:
depends_on:

- database

Info

docker info

Docker Swarm

Nodes

Manager Nodes

They assign tasks and ensure that the swarm's status always remains correct. There is always a node leader.

Worker Nodes

Executes the tasks

Initialise

docker swarm init

Creates a manager node on the current node

Token to join manager

docker swarm join-token worker | manager

Add manager node

docker swarm join --token SWMTKN-1-3t516o9d5wo36ao2fyh8w5ma4oqmithampjm87jq163r29ihpd-1fyx2ecncnyd5be99oavt8fl4 192.168.65.3:2377

Options

• --advertise-addr Define address to connect to
• --replicas=5 How many replicas to create

Show nodes

docker node ls

Informationen about node

docker node inspect –pretty a1b3 //a1b3= Teil der Node-Id

Show running tasks in node

Docker node ps [node]

Remove node out of swarm

docker swarm [--force] leave

• Managers should be removed last.
• Managers must be specified with –force, otherwise it will be ignored.

Remove node

docker node rm [node]

Geht erst, wenn der Node aus dem Swarm entfernt ist

Promote to manager node

docker node promote [node]

Degrade/Demote

docker node demote [node]

Services

Create service

docker service create <image>

• -p Portmapping (like docker run)

Show all services

docker service ls

Show tasks in service

docker service ps <node>

Remove service

docker service rm <service>

Update docker service

docker service update <service>

Example

docker service update --replicas=6 my_service
docker service update --replicas=3 --publish-add published=8080,target=80 my_service

Change scaling

docker service scale my_service=4

Undo changes

Docker service rollback my_service

Log services/tasks

docker service logs service|task

Details about service

Docker service inspect <service>

Docker Config

Config files can be created and added to the swarm. They are then available to all nodes (text, binary). Only works with swarm services.

Create config

docker config create <Config_name> <Config-File>
or
docker config create <Config_name> - Liest von StdIn ein

List configs

docker config ls

Show details of config

docker config inspect --pretty <config_name>

Pass config to service

docker service create --name my_redis --config my_config --replicas=3 redis:alpine

Remove config

First remove from all services

docker service update --config-rm my_config my_redis

after that

docker config rm my_config

Docker Secrets

Ähnlich wie config nur verschlüsselt und nur für

Erzeugen eines Secret

docker secret create <secret_name> <Config-File>
or
docker secret create <secret_name> - Liest von StdIn ein

List all secrets

docker secret ls

Show details of secret

docker secret inspect --pretty <secret_name>

Pass secret to service

docker service create --name my_redis --secret my_secret --replicas=3 redis:alpine

Remove secret

First remove from all services

docker service update --secret-rm my_secret my_redis

after that

docker secret rm my_secret

Docker Stack

Similar to docker-compose but for swarm services (definition of services, configs, secrets, replicas,…) in a yaml file