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Docker Days - Docker community blog from DBAref.com

Flocker is an open-source container data volume manager for your Dockerized applications.
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Codefresh lets you instantly build and test Docker images and compositions.You can start by going to our Getting Started Guide or watching this short video on how to build your first Docker image.

Starting, stopping, restarting docker container

posted May 8, 2016, 5:28 PM by Sachchida Ojha

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1. docker start <container name>
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PS C:\Program Files\Docker Toolbox> docker start --help

Usage:  docker start [OPTIONS] CONTAINER [CONTAINER...]

Start one or more stopped containers

  -a, --attach         Attach STDOUT/STDERR and forward signals
  --detach-keys        Override the key sequence for detaching a container
  --help               Print usage
  -i, --interactive    Attach container's STDIN
PS C:\Program Files\Docker Toolbox>

2. docker stop <container name>
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PS C:\Program Files\Docker Toolbox> docker stop --help

Usage:  docker stop [OPTIONS] CONTAINER [CONTAINER...]

Stop a running container.
Sending SIGTERM and then SIGKILL after a grace period

  --help             Print usage
  -t, --time=10      Seconds to wait for stop before killing it

3. docker start <container name>
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PS C:\Program Files\Docker Toolbox> docker restart --help

Usage:  docker restart [OPTIONS] CONTAINER [CONTAINER...]

Restart a container

  --help             Print usage
  -t, --time=10      Seconds to wait for stop before killing the container
PS C:\Program Files\Docker Toolbox>
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Docker Elements

posted May 7, 2016, 4:20 PM by Sachchida Ojha   [ updated May 7, 2016, 4:48 PM ]

1. Docker Containers: Docker containers wrap up a piece of software in a complete file system that contains everything it needs to run: code, runtime, system tools, system libraries – anything you can install on a server. This guarantees that it will always run the same, regardless of the environment it is running in. A container is basically the actual directory on a computer which contains everything in the docker application which you are going to launch. A container is an active (or inactive if exited) stateful instantiation of an image.

2. Docker Images: Basically snapshot of a container which contains base operating systems and all iterative changes made. An image is an ordered collection of root file system changes and the corresponding execution parameters for use within a container runtime. Images are read-only.

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Images are frozen immutable snapshots of live containers. Containers are running (or stopped) instances of some image. Answering from a Java developer perspective, difference between a Docker Image and a Docker Container is the same as that of difference between a Java Class and an Object. In practice, Object is the runtime instance of a Class. Similarly, Container is the runtime instance of an Image. Object gets created only once it is instantiated. Similarly Container can be running or stopped. And containers are created out of an image. When using docker, we start with a base image. We boot it up, do changes and the changes are saved in layers forming another image. So eventually I have an image for my postgres and an image for my web app, changes to which keep on being persisted. Images are created with the build command, and they'll produce a container when started with run. Images are stored in a Docker registry such as registry.hub.docker.com. Because they can become quite large, images are designed to be composed of layers of other images, allowing a miminal amount of data to be sent when transferring images over the network.
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3. Docker Files: Docker files are scripts that automates the build process for creating an image. Docker can build images automatically by reading the instructions from a Dockerfile. A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. Using docker build users can create an automated build that executes several command-line instructions in succession.

Best practices for writing Dockerfiles

Docker can build images automatically by reading the instructions from a Dockerfile, a text file that contains all the commands, in order, needed to build a given image. Dockerfiles adhere to a specific format and use a specific set of instructions. You can learn the basics on the Dockerfile Reference page. If you’re new to writing Dockerfiles, you should start there.

Docker parts

posted May 7, 2016, 4:07 PM by Sachchida Ojha   [ updated May 7, 2016, 4:18 PM ]

1. Docker Daemon: The Docker daemon is the persistent process that manages containers. Docker uses the same binary for both the daemon and client.

2. Docker CLI (command line interface):

PS C:\Program Files\Docker Toolbox> docker
Usage: docker [OPTIONS] COMMAND [arg...]
       docker daemon [ --help | ... ]
       docker [ --help | -v | --version ]

A self-sufficient runtime for containers.

Options:

  -b, --bridge                                                         Attach containers to a virtual switch
  --config=%USERPROFILE%\.docker                                       Location of client config files
  -D, --debug                                                          Enable debug mode
  -H, --host=[]                                                        Daemon socket(s) to connect to
  -h, --help                                                           Print usage
  -l, --log-level=info                                                 Set the logging level
  --tls                                                                Use TLS; implied by --tlsverify
  --tlscacert=%USERPROFILE%\.docker\machine\machines\default\ca.pem    Trust certs signed only by this CA
  --tlscert=%USERPROFILE%\.docker\machine\machines\default\cert.pem    Path to TLS certificate file
  --tlskey=%USERPROFILE%\.docker\machine\machines\default\key.pem      Path to TLS key file
  --tlsverify=true                                                     Use TLS and verify the remote
  -v, --version                                                        Print version information and quit

Commands:
    attach    Attach to a running container
    build     Build an image from a Dockerfile
    commit    Create a new image from a container's changes
    cp        Copy files/folders between a container and the local filesystem
    create    Create a new container
    diff      Inspect changes on a container's filesystem
    events    Get real time events from the server
    exec      Run a command in a running container
    export    Export a container's filesystem as a tar archive
    history   Show the history of an image
    images    List images
    import    Import the contents from a tarball to create a filesystem image
    info      Display system-wide information
    inspect   Return low-level information on a container or image
    kill      Kill a running container
    load      Load an image from a tar archive or STDIN
    login     Log in to a Docker registry
    logout    Log out from a Docker registry
    logs      Fetch the logs of a container
    network   Manage Docker networks
    pause     Pause all processes within a container
    port      List port mappings or a specific mapping for the CONTAINER
    ps        List containers
    pull      Pull an image or a repository from a registry
    push      Push an image or a repository to a registry
    rename    Rename a container
    restart   Restart a container
    rm        Remove one or more containers
    rmi       Remove one or more images
    run       Run a command in a new container
    save      Save one or more images to a tar archive
    search    Search the Docker Hub for images
    start     Start one or more stopped containers
    stats     Display a live stream of container(s) resource usage statistics
    stop      Stop a running container
    tag       Tag an image into a repository
    top       Display the running processes of a container
    unpause   Unpause all processes within a container
    update    Update configuration of one or more containers
    version   Show the Docker version information
    volume    Manage Docker volumes
    wait      Block until a container stops, then print its exit code

Run 'docker COMMAND --help' for more information on a command.
PS C:\Program Files\Docker Toolbox>


3. Docker Image Index 

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