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Docker - Hands On

Make your hands dirty with some docker related exercises.

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By Sakharam Shinde
4 min read
Docker - Hands On

Docker - Hands On

Docker Version

  1. Check the docker version installed on your machine

    • Command:
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     docker version
    • Output:
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     Client:
   Version:           27.2.0
   API version:       1.47
   Go version:        go1.21.13
   Git commit:        3ab4256
   Built:             Tue Aug 27 14:17:17 2024
   OS/Arch:           windows/amd64
   Context:           desktop-linux

 Server: Docker Desktop 4.34.2 (167172)
 Engine:
   Version:          27.2.0
   API version:      1.47 (minimum version 1.24)
   Go version:       go1.21.13
   Git commit:       3ab5c7d
   Built:            Tue Aug 27 14:15:15 2024
   OS/Arch:          linux/amd64
   Experimental:     false
 containerd:
   Version:          1.7.20
   GitCommit:        8fc6bcff51318944179630522a095cc9dbf9f353
 runc:
   Version:          1.1.13
   GitCommit:        v1.1.13-0-g58aa920
 docker-init:
   Version:          0.19.0
   GitCommit:        de40ad0
    • Docker uses a client-server architecture, so the docker client and docker server can run independently.
    • Docker uses containerd container engine and runc as a container runtime.
    • containerd
      • A container runtime that manages the entire container lifecycle from image transfer to storage, execution, and supervision.
      • Role in Docker:
        • Acts as an abstraction layer between Docker’s CLI/API and the lower-level runtimes (like runc).
        • Responsible for pulling images, managing container snapshots, and interacting with the underlying runtime.
      • Key Features:
        • Supports container creation and management.
        • Handles container storage and networking.
        • Provides advanced features like checkpoint/restore for containers.
      • Relation to Docker:
        • Docker relies on containerd to manage the high-level container lifecycle processes.
        • It ensures efficient and seamless interaction between the Docker engine and the OS-level runtime.
    • runc
      • A lightweight, low-level container runtime that implements the Open Container Initiative (OCI) Runtime Specification.
      • Role in Docker:
        • Directly interacts with the Linux kernel to create and run containers.
        • Configures namespaces, cgroups, and other Linux primitives required for container isolation and resource management.
      • Key Features:
        • Executes container processes in isolated environments.
        • Provides minimal overhead, improving performance.
        • Compatible with OCI standards, ensuring interoperability across tools.
      • Relation to Docker:
        • When you execute a docker run command, Docker:
        • Invokes containerd to manage the container lifecycle.
        • containerd calls runc to perform the actual setup and execution of the container on the system.
    • How do containerd and runc work together in Docker’s Architecture:
      • Docker CLI/Daemon interacts with containerd for high-level container operations (e.g., creating, starting, and stopping containers).
      • containerd delegates the low-level container runtime tasks to runc, which handles the kernel-level operations for container isolation and execution.

  2. Check the configuration information about Docker

  • Command:

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      docker info

  • Output:

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      Client:
    Version:    27.2.0
    Context:    desktop-linux
    Debug Mode: false
    Plugins:
      buildx: Docker Buildx (Docker Inc.)
        Version:  v0.16.2-desktop.1
        Path:     C:\Program Files\Docker\cli-plugins\docker-buildx.exe
      compose: Docker Compose (Docker Inc.)
        Version:  v2.29.2-desktop.2
        Path:     C:\Program Files\Docker\cli-plugins\docker-compose.exe
      debug: Get a shell into any image or container (Docker Inc.)
        Version:  0.0.34
        Path:     C:\Program Files\Docker\cli-plugins\docker-debug.exe
      desktop: Docker Desktop commands (Alpha) (Docker Inc.)
        Version:  v0.0.15
        Path:     C:\Program Files\Docker\cli-plugins\docker-desktop.exe
      dev: Docker Dev Environments (Docker Inc.)
        Version:  v0.1.2
        Path:     C:\Program Files\Docker\cli-plugins\docker-dev.exe
      extension: Manages Docker extensions (Docker Inc.)
        Version:  v0.2.25
        Path:     C:\Program Files\Docker\cli-plugins\docker-extension.exe
      feedback: Provide feedback, right in your terminal! (Docker Inc.)
        Version:  v1.0.5
        Path:     C:\Program Files\Docker\cli-plugins\docker-feedback.exe
      init: Creates Docker-related starter files for your project (Docker Inc.)
        Version:  v1.3.0
        Path:     C:\Program Files\Docker\cli-plugins\docker-init.exe
      sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
        Version:  0.6.0
        Path:     C:\Program Files\Docker\cli-plugins\docker-sbom.exe
      scout: Docker Scout (Docker Inc.)
        Version:  v1.13.0
        Path:     C:\Program Files\Docker\cli-plugins\docker-scout.exe

  Server:
    Containers: 3
      Running: 1
      Paused: 0
      Stopped: 2
    Images: 8
    Server Version: 27.2.0
      Storage Driver: overlayfs
      driver-type: io.containerd.snapshotter.v1
    Logging Driver: json-file
    Cgroup Driver: cgroupfs
    Cgroup Version: 1
    Plugins:
      Volume: local
      Network: bridge host ipvlan macvlan null overlay
      Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
    Swarm: inactive
    Runtimes: nvidia runc io.containerd.runc.v2
    Default Runtime: runc
    Init Binary: docker-init
    containerd version: 8fc6bcff51318944179630522a095cc9dbf9f353
    runc version: v1.1.13-0-g58aa920
    init version: de40ad0
    Security Options:
      seccomp
      Profile: unconfined
    Kernel Version: 5.15.153.1-microsoft-standard-WSL2
    Operating System: Docker Desktop
    OSType: linux
    Architecture: x86_64
    CPUs: 12
    Total Memory: 7.607GiB
    Name: docker-desktop
    ID: bdca1064-96c9-4253-b78a-a55e08270f42
    Docker Root Dir: /var/lib/docker
    Debug Mode: false
    HTTP Proxy: http.docker.internal:3128
    HTTPS Proxy: http.docker.internal:3128
    No Proxy: hubproxy.docker.internal
    Labels:
      com.docker.desktop.address=npipe://\\.\pipe\docker_cli
    Experimental: false
    Insecure Registries:
      hubproxy.docker.internal:5555
      127.0.0.0/8
    Live Restore Enabled: false

Running Containers

  1. Run a ubuntu container using interactive terminal

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     docker run -it ubuntu bash

  2. Run a ubuntu container and get the output of file /etc/os-release and remove the container

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     docker run --rm ubuntu cat /etc/os-release

  3. Run a nginx container in background and remove it when stopped

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     docker run -d --rm nginx

  4. Run a nginxcontainer in the background and expose the port

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     docker run -d --rm -P nginx

  5. Run a nginx container in the background with a specific port

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     docker run -d --rm -p 12334:80 nginx

  6. Run a nginx container in the background in interactive mode and mount a volumne containing local folder. Make change to a the file and check if they are reflect on the nginx home page

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     cd C:\Users\Sakharam.Shinde
 mkdir homepage
 echo "Hello Nginx from Sakharam" > homepage/index.html
 docker run -d --rm -p 12334:80 -v C:/Users/Sakharam.Shinde/homepage:/usr/share/nginx/html nginx
 curl localhost:12334
 echo "Shinde" >> homepage/index.html
 curl localhost:12334
devops, orchestration, docker
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This post is licensed under CC BY 4.0 by the author.