Docker_Commands.md

How to Install Docker

• First, update your existing list of packages:

  ->sudo apt update

• Next, install a few prerequisite packages which let apt use packages over HTTPS:

  ->sudo apt install apt-transport-https ca-certificates curl software-properties-common

• Then add the GPG key for the official Docker repository to your system:

  ->curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -

• Add the Docker repository to APT sources:

  ->sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu bionic stable"

• Next, update the package database with the Docker packages from the newly added repo:

  ->sudo apt-get update

• Make sure you are about to install from the Docker repo instead of the default Ubuntu repo:

  ->apt-cache policy docker-ce

• You’ll see output like this, although the version number for Docker may be different:

docker-ce:
  Installed: (none)
  Candidate: 18.03.1~ce~3-0~ubuntu
  Version table:
     18.03.1~ce~3-0~ubuntu 500
        500 https://download.docker.com/linux/ubuntu bionic/stable amd64 Packages

Finally, install Docker:

->sudo apt install docker-ce

• Docker should now be installed, the daemon started, and the process enabled to start on boot. Check that it’s running:

Output
● docker.service - Docker Application Container Engine
   Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
   Active: active (running) since Thu 2018-07-05 15:08:39 UTC; 2min 55s ago
     Docs: https://docs.docker.com
 Main PID: 10096 (dockerd)
    Tasks: 16
   CGroup: /system.slice/docker.service
           ├─10096 /usr/bin/dockerd -H fd://
           └─10113 docker-containerd --config /var/run/docker/containerd/containerd.toml

Executing the Docker Command Without Sudo (Optional)

• If you want to avoid typing sudo whenever you run the docker command, add your username to the docker group:

  ->sudo usermod -aG docker ${USER}

• To apply the new group membership, log out of the server and back in, or type the following:

  ->su - ${USER}

• You will be prompted to enter your user’s password to continue.

• Confirm that your user is now added to the docker group by typing:

  ->id -nG

Output
<Your Username> sudo docker

• If you need to add a user to the docker group that you’re not logged in as, declare that username explicitly using:

  ->sudo usermod -aG docker username

How to use Docker

• To build Docker image

  -> docker build -t <application_name> .

• To Check Docker Images

  -> docker images

• To create and run docker at once

  -> docker run -i -t <Image_ID || Image_name> /bin/bash

• Another method to create container

  -> docker create --name <give_name_of_container> <Image_Name>

• To start Docker

  ->docker start <container_name || container_ID>

• To run conatiner if crteated container using above command

  ->docker exec -it <container_name> bash

• Remove a Docker image

  -> docker rmi <docker_image_id>

• Remove a Docker container

  -> docker rm <container_name || container ID>

• Show Running Containers

  -> docker ps

• Show all Running Containers

  -> docker ps -a

• Stop Container

  -> docker stop <container_id>