How to use the Docker on Ubuntu 16.04

First, the use of Docker hub

Docker Hub is the official Docker maintenance warehouse, which already contains a lot of mirrors, generally our needs directly in the official warehouse search can be resolved. In the official public warehouse we can search and download images without having to log in.

Search by Docker Search command

Docker pull command to download

Search Image Command Detailed usage: Docker search [OPTIONS] Term

[Email protected]:~# sudo docker pull Ubuntu
Using default Tag:latest
Latest:pulling from Library/ubuntu
Af49a5ceb2a5:pull Complete
8f9757b472e7:pull Complete
E931b117db38:pull Complete
47b5e16c0811:pull Complete
9332eaf1a55b:pull Complete
Digest:sha256:3b64c309deae7ab0f7dbdd42b6b326261ccd6261da5d88396439353162703fb5
status:downloaded newer image for Ubuntu:latest

Once you're done, you can use the image at any time, such as creating a container to run the Bash app.

$ sudo docker run -t -i ubuntu /bin/bash[email protected]:/#

Docker images list mirrors

$ sudo docker imagesREPOSITORY       TAG      IMAGE ID      CREATED      VIRTUAL SIZEubuntu           latest   99ec81b80c55  4 weeks ago  266 MB

In the listing information, you can see several field information

• from which warehouse, such as Ubuntu
• Mirrored tags, such as 14.04
• It's ID number (unique)
• Creation time
• Mirror size

Where the mirrors ID uniquely identify the mirror, notice ubuntu:14.04 and ubuntu:trusty have the same image ID , stating that they are actually the same mirror.

TAGInformation is used to mark different images from the same warehouse. For example, ubuntu there are multiple mirrors in the warehouse, and information is available TAG to differentiate the distribution, for example,,,, 10.04 , and 12.04 12.10 13.04 14.04 so on. For example, the following command specifies that mirroring is used ubuntu:14.04 to start a container.

$ sudo docker run -t -i ubuntu /bin/bash

If you do not specify a specific tag, the tag information is used by default latest .

REPOSITORY TAG IMAGE ID CREATED SIZE
Ubuntu latest 4CA3A192FF2A 2 weeks ago 128.2 MB

The Docker commit command to submit the updated copy.

$ sudo docker commit -m "Added json gem" -a "Docker Newbee" 0b2616b0e5a8 ouruser/sinatra:v24f177bd27a9ff0f6dc2a830403925b5360bfe0b93d476f7fc3231110e7f71b1c

Where -m you specify the descriptive information for the submission, like the version Control tool we use, -a you can specify updated user information, then the ID of the container used to create the mirror, and finally specify the warehouse name and tag information for the target image. The ID information for this image is returned when the creation is successful.

Use docker images to view the newly created image.

$ sudo docker imagesREPOSITORY          TAG     IMAGE ID       CREATED       VIRTUAL SIZEubuntu              latest   99ec81b80c55  4 weeks ago   266 MBouruser/sinatra     v2      3c59e02ddd1a   10 hours ago  446.7 MB

After that, you can use the new mirror to start the container

$ sudo docker run -t -i ouruser/sinatra:v2 /bin/bash[email protected]:/#

Docker Save and Docker load Import export Image

If you want to export the image to a local file, you can use the docker save command.

$ sudo docker imagesREPOSITORY          TAG                 IMAGE ID            CREATED             VIRTUAL SIZEubuntu              latest              c4ff7513909d        5 weeks ago         225.4 MB...$sudo docker save -o ubuntu.tar ubuntu

You can use the docker load local file from the export to import to the local mirror library, for example

$ sudo docker load --input ubuntu.tar

Or

$ sudo docker load < ubuntu.tar

This imports the image and its associated metadata information (including tags, and so on).

Docker rmi Remove Mirror

$ sudo docker rmi ouruser/sinatra:v2Untagged: ouruser/sinatra:v2Deleted: 5bc342fa0b91cabf65246837015197eecfa24b2213ed6a51a8974ae250fedd8dDeleted: ed0fffdcdae5eb2c3a55549857a8be7fc8bc4241fb19ad714364cbfd7a56b22fDeleted: 5c58979d73ae448df5af1d8142436d81116187a7633082650549c52c3a2418f0

* Note: Delete docker rm all containers that depend on this image before deleting the image.

container of the 5.Docker Command (container)Docker run boot container

There are two ways to start a container, one is to create a new container based on the mirror and start, and the other is to restart the container in the terminating state (stopped).

Because Docker containers are too lightweight, many times users are deleting and creating new containers at any time.

New and started

The required commands are mainly for docker run .

For example, the following command outputs a "Hello world" and then terminates the container.

$ sudo docker run ubuntu /bin/echo ‘Hello world‘Hello world

This is almost indistinguishable from local direct execution /bin/echo ‘hello world‘ .

The following command launches a bash terminal that allows the user to interact.

$ sudo docker run -t -i ubuntu /bin/bash[email protected]:/#

Where the -t option allows Docker to assign a pseudo terminal (Pseudo-tty) and bind to the container's standard input, leave -i the container's standard input open.

In interactive mode, users can enter commands through the terminal they create, such as

[email protected]:/# lsbin boot dev etc home lib lib64 media mnt opt proc root run sbin srv sys tmp usr var

More often, you need to let the Docker container run in the background in a daemon (daemonized) mode. At this point, you can add -d parameters to implement.

For example, the following command runs the container in the background.

$ sudo docker run -d ubuntu /bin/sh -c "while true; do echo hello world; sleep 1; done"1e5535038e285177d5214659a068137486f96ee5c2e85a4ac52dc83f2ebe4147

When the container starts, it returns a unique ID, or the docker ps container information can be viewed through a command.

$ sudo docker psCONTAINER ID  IMAGE         COMMAND               CREATED        STATUS       PORTS NAMES1e5535038e28  ubuntu        /bin/sh -c ‘while tr  2 minutes ago  Up 1 minute        insane_babbage

To get the output information for a container, you can pass the docker logs command.

$ sudo docker logs insane_babbagehello worldhello worldhello world. . .

When used docker run to create a container, the standard operations that Docker runs in the background include:

• Checks if there is a specified image locally and does not exist to download from the public repository
• Create and start a container with mirroring
• Assign a file system and mount a layer of read-write layers outside the mirrored layer
• Bridging a virtual interface into a container from the bridge interface configured by the host host
• Configure an IP address from the address pool to the container
• Executing user-specified applications
• Container is terminated when execution is complete

start a terminated container

The command can be used to docker start start a terminated container directly.

The core of the container is the application that is executed, and the resources required are required for the application to run. In addition, there are no other resources. You can use ps or view process information in a pseudo terminal top .

[email protected]:/# ps  PID TTY          TIME CMD    1 ?        00:00:00 bash   11 ?        00:00:00 ps

Visible, only the specified bash app is running in the container. This feature makes Docker highly utilized for resources and is a genuine lightweight virtualization.

Can be used docker stop to terminate a running container.

In addition, the container terminates automatically when the application specified in the Docker container is terminated. For example, in the previous section, only a container for a terminal was started, and when the user exit exits the terminal by command or, the container that is Ctrl+d created terminates immediately.

The container of the terminating state can be seen with the docker ps -a command. For example

sudo docker ps -aCONTAINER ID        IMAGE                    COMMAND                CREATED             STATUS                          PORTSNAMESba267838cc1b        ubuntu                   "/bin/bash"            30 minutes ago      Exited (0) About a minute ago   trusting_newton1e5535038e28        ubuntu                    /bin/sh -c ‘while tr  2 minutes ago       Up 1 minute                     insane_babbage

A container in the terminating state, which can be docker start restarted by command.

In addition, the docker restart command terminates a run-state container and then restarts it.

When using -dparameter, the container starts to enter the background when it is started. There are a number of ways to get into a container at some point, including using docker attach commands or nsenter tools.

docker attachIs the command that comes with Docker. The following example how to use this command.

$ sudo docker run -idt ubuntu243c32535da7d142fb0e6df616a3c3ada0b8ab417937c853a9e1c251f499f550$ sudo docker psCONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES243c32535da7        ubuntu:latest       "/bin/bash"         18 seconds ago      Up 17 seconds                           nostalgic_hypatia$sudo docker attach nostalgic_hypatia[email protected]:/#

An example is given above.

Import and export containers for Docker import and Docker export

If you want to export a local container, you can use the docker export command.

$ sudo docker ps -aCONTAINER ID        IMAGE               COMMAND             CREATED             STATUS                    PORTS               NAMES7691a814370e        ubuntu:14.04        "/bin/bash"         36 hours ago        Exited (0) 21 hours ago                       test$ sudo docker export 7691a814370e > ubuntu.tar

This will export the container snapshot to a local file.

You can use the docker import import from a container snapshot file as a mirror, for example

$ cat ubuntu.tar | sudo docker import - test/ubuntu:v1.0$ sudo docker imagesREPOSITORY          TAG                 IMAGE ID            CREATED              VIRTUAL SIZEtest/ubuntu         v1.0                9d37a6082e97        About a minute ago   171.3 MB

Alternatively, you can import by specifying a URL or a directory, such as

$sudo docker import http://example.com/exampleimage.tgz example/imagerepo

* Note: Users can use both to docker load import a mirrored storage file to a local mirror library, or to docker import import a container snapshot to a local mirror library. The difference between the two is that the container snapshot file discards all history and metadata information (that is, only the snapshot state of the container at that time), while the mirrored storage file will hold the full record and be larger in size. In addition, metadata information such as labels can be re-specified when importing from a container snapshot file.

Delete ContainerDocker RM to delete a container that is in the signaled state. For example

$sudo docker rm  trusting_newtontrusting_newton

If you want to delete a running container, you can add -f parameters. Docker sends a SIGKILL signal to the container.

More commands can be viewed in the terminal input Docker--help.

How to use the Docker on Ubuntu 16.04