In today’s post we’ll look at Docker containers. Containers are lightweight application virtualization platforms that are isolated, but contrary to virtual machines, they share resources with the host OS. They are faster and less resource intensive than traditional VMs.
docker --help
Usage: docker COMMAND
A self-sufficient runtime for containers
Options:
--config string Location of client config files (default "/root/.docker")
-D, --debug Enable debug mode
-H, --host list Daemon socket(s) to connect to
-l, --log-level string Set the logging level ("debug"|"info"|"warn"|"error"|"fatal") (default "info")
--tls Use TLS; implied by --tlsverify
--tlscacert string Trust certs signed only by this CA (default "/root/.docker/ca.pem")
--tlscert string Path to TLS certificate file (default "/root/.docker/cert.pem")
--tlskey string Path to TLS key file (default "/root/.docker/key.pem")
--tlsverify Use TLS and verify the remote
-v, --version Print version information and quit
Management Commands:
config Manage Docker configs
container Manage containers
image Manage images
network Manage networks
node Manage Swarm nodes
plugin Manage plugins
secret Manage Docker secrets
service Manage services
swarm Manage Swarm
system Manage Docker
trust Manage trust on Docker images
volume Manage volumes
Commands:
attach Attach local standard input, output, and error streams 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 to files or directories 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 Docker objects
kill Kill one or more running containers
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
pause Pause all processes within one or more containers
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 one or more containers
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 (streamed to STDOUT by default)
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 one or more running containers
tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
top Display the running processes of a container
unpause Unpause all processes within one or more containers
update Update configuration of one or more containers
version Show the Docker version information
wait Block until one or more containers stop, then print their exit codes
Run 'docker COMMAND --help' for more information on a command.
docker search hello
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
hello-world Hello World! (an example of minimal Dockeriz… 495 [OK]
Pull the image:
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docker pull hello-world
Using default tag: latest
latest: Pulling from library/hello-world
9bb5a5d4561a: Pull complete
Digest: sha256:f5233545e43561214ca4891fd1157e1c3c563316ed8e237750d59bde73361e77
Status: Downloaded newer image for hello-world:latest
Run the demo image:
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docker run hello-world
Hello from Docker!
This message shows that your installation appears to be working correctly.
To generate this message, Docker took the following steps:
1. The Docker client contacted the Docker daemon.
2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
(amd64)
3. The Docker daemon created a new container from that image which runs the
executable that produces the output you are currently reading.
4. The Docker daemon streamed that output to the Docker client, which sent it
to your terminal.
To try something more ambitious, you can run an Ubuntu container with:
$ docker run -it ubuntu bash
Share images, automate workflows, and more with a free Docker ID:
https://hub.docker.com/
For more examples and ideas, visit:
https://docs.docker.com/engine/userguide/
The Docker default storage is at /var/lib/docker. Now let’s go beyond the basics and get an Ubuntu image:
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu latest c9d990395902 9 days ago 113MB
hello-world latest e38bc07ac18e 10 days ago 1.85kB
Run a command inside the Ubuntu container:
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docker run ubuntu uname -a
Linux 05f2f247622a 3.10.0-693.17.1.el7.x86_64 #1 SMP Thu Jan 25 20:13:58 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
Check all containers:
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docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
05f2f247622a ubuntu "uname -a" About a minute ago Exited (0) About a minute ago naughty_fermi
db7d3fcd06a7 hello-world "/hello" 10 minutes ago Exited (0) 9 minutes ago trusting_mirzakh
Take note of the container ID if you want to start a specific container:
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docker start 05f2f247622a
05f2f247622a
To start an interactive session in the container with an allocated TTY, do the following:
Here we’ve run the bash shell inside the container. To return to the host, type exit
We’ve only scratched the surface, but we can see how powerful and versatile Docker containers can be.
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/ Be free and open and breezy! Enjoy! \
| Things won't get any better so get used |
\ to it. /
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\ ^__^
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