- What is Docker
- Running a Container
- Networking
- Storage
- Stopping a Container
- Images
- Dockerfile
- Docker Registry
- Docker Image Storage
- Cleanup
Docker is a self-contained sealed unit of software with all the requirements to run the software.
Container
- Code
- Config
- Processes
- Networking
- Dependencies
|---------| docker run |------------------|
| Image | -----------------> | Running Container| -------|
|_________| |__________________| |
| exit
|-------------| docker commit |-------------------| |
| New Image | <------------- | Stopped Container |<------|
|_____________| |___________________|
Run a container in interactive terminal (--ti) mode.
$ docker run -ti ubuntu bash
root@a23acba9d7ea:/# exit
$
Run a command and remove (--rm) the container.
$ docker run --rm ubuntu echo Hello World
Hello World
$
Run a container in detached mode.
$ docker run -d -ti ubuntu bash
d6fb4e90102b57063e54a3283bd50ba268c7cb83fb8d0b1b7538d6f90b719bfc
$
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d6fb4e90102b ubuntu "bash" 3 seconds ago Up 4 seconds condescending_hugle
Attach to a running container.
$ docker attach d6fb4e90102b
root@d6fb4e90102b:/# ^P ^Q # to detach from a container.
$
Start container with a listening port.
$ docker run --rm -ti -d -p 9999:9999 -p 9997:9997 --name echo-server ubuntu:14.04 nc -lp 9999
16d14a5209db42408f6bdf6620b4f108554fd73650980cb221c12762f63c70ca
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
16d14a5209db ubuntu:14.04 "nc -lp 9999" Less than a second ago Up 3 seconds 0.0.0.0:9997->9997/tcp, 0.0.0.0:9999->9999/tcp echo-server
Check the avalable ports.
$ docker port echo-server
9999/tcp -> 0.0.0.0:9999
9997/tcp -> 0.0.0.0:9997
Linking docker containers. Once the link breaks the connection won't be established.
$ docker run --rm -ti --name server ubuntu:14.04 bash
root@b5b20c20b3f8:/# nc -lp 9999
hello
$ docker run --rm -ti --link server --name client ubuntu:14.04 bash
root@573cf83a68a6:/# nc server 9999
hello
Dynamic linking. The conenction will be established even after connection break.
$ docker network create my_network
ddbd824c8de2ebd4abf2cc2cdc3e703b34a25789b70409618f64b6cfaaa96d52
$ docker network list
NETWORK ID NAME DRIVER SCOPE
ddbd824c8de2 my_network bridge local
$ docker run --rm -ti --name server --net=example ubuntu:14.04 bash
root@25eaaf4a0a85:/# nc -lp 9999
hello
$ docker run --rm -ti --link server --name client --net=example ubuntu:14.04 bash
root@94c4a5251ad7:/# nc server 9999
hello
Permanent volume. The data will be available even after destroying containers. -v local_dir:shared_dir.
$ docker run --rm -ti -v /Python:/shared_Volume ubuntu:14.04 bash
Ephemeral volume. The data will be destroyed once all the containers inheriting the volume is destroyed.
$ docker run --rm -ti -v /shared_Volume ubuntu:14.04 bash
$ docker run --rm -ti -v /shared_Volume --volumes-from 188947a78295 ubuntu:14.04 bash
Use exit if connected to container or use kill a detached running container.
$ docker kill c3dc43d18170
c3dc43d18170
Check the containers
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c3dc43d18170 ubuntu "bash" 5 seconds ago Exited (137) 3 seconds ago hungry_noyce
ffc8d7f40dbf ubuntu "bash" 36 seconds ago Exited (0) 47 seconds ago upbeat_johnson
46d69c4db84c ubuntu "bash ls" 14 minutes ago Exited (126) 14 minutes ago zen_haibt
Check the logs of a stopped container.
$ docker logs 46d69c4db84c
/bin/ls: /bin/ls: cannot execute binary file
List all local images.
$ docker images -a
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu latest c9d990395902 7 days ago 113MB
Creating an image from container.
$ docker commit 5d91817ac797 my-ubuntu
sha256:224dc2cbf7d538daa9d8da5d1e9bd48ea1abca2c2e78d6754245e6089d620884
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
my-ubuntu latest 224dc2cbf7d5 Less than a second ago 223MB
ubuntu 16.04 c9d990395902 7 days ago 113MB
ubuntu 14.04 3b853789146f 7 days ago 223MB
Creating an image with custom tag.
$ docker commit 5d91817ac797 my-ubuntu:prod
sha256:9a340be12d4676e40ff94ae31cfa7c4daddfa1dbb15643a311c06e9fabfde15f
roadbodysat-lm:Python gsree$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
my-ubuntu prod 9a340be12d46 Less than a second ago 223MB
my-ubuntu latest 224dc2cbf7d5 About a minute ago 223MB
ubuntu 16.04 c9d990395902 7 days ago 113MB
ubuntu 14.04 3b853789146f 7 days ago 223MB
Pulling an image to local repo.
$ docker pull debian
Using default tag: latest
latest: Pulling from library/debian
c73ab1c6897b: Pull complete
Digest: sha256:c908a4fcb2b2a1953bd40ebc12d9a4116868d72540efc27502ee6c2395b8a1e9
Status: Downloaded newer image for debian:latest
Pushing a new image to registry.
$ docker push registry-host:5000/myadmin/my-ubuntu
Tag an image.
$ docker tag my-ubuntu:prod my-ubuntu:v2.0
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
my-ubuntu v2.0 9a340be12d46 8 minutes ago 223MB
Searching for an image.
$ docker search ubuntu
NAME DESCRIPTION STARS OFFICIAL AUTOMATED
ubuntu Ubuntu is a Debian-based Linux operating sys… 7535 [OK]
dorowu/ubuntu-desktop-lxde-vnc Ubuntu with openssh-server and NoVNC 179 [OK]
~~~~~~~~~ truncate ~~~~~~~
Dockerfile is used to build a custom image.
$ cat Dockerfile
FROM ubuntu:16.04
RUN echo "This is a custom build"
RUN echo "This is Second echo"
CMD echo "Hello World!"
Build the image from Dockerfile.
$ docker build -t ubuntu_nc .
Sending build context to Docker daemon 3.284MB
Step 1/4 : FROM ubuntu:16.04
---> c9d990395902
Step 2/4 : RUN echo "This is a custom build"
---> Running in f618feb446ac
This is a custom build
Removing intermediate container f618feb446ac
---> 5e1c92b4bac5
Step 3/4 : RUN echo "This is Second echo"
---> Running in b2c3c8df0fb0
This is Second echo
Removing intermediate container b2c3c8df0fb0
---> 5fa385dc0f52
Step 4/4 : CMD echo "Hello World!"
---> Running in f85aacbf1ad8
Removing intermediate container f85aacbf1ad8
---> 999652aca5b2
Successfully built 999652aca5b2
Successfully tagged ubuntu_nc:latest
Create a docker registry container.
$ docker run -d -p 5000:5000 --restart=always --name registry registry:2
Unable to find image 'registry:2' locally
2: Pulling from library/registry
81033e7c1d6a: Pull complete
b235084c2315: Pull complete
c692f3a6894b: Pull complete
ba2177f3a70e: Pull complete
a8d793620947: Pull complete
Digest: sha256:672d519d7fd7bbc7a448d17956ebeefe225d5eb27509d8dc5ce67ecb4a0bce54
Status: Downloaded newer image for registry:2
d17b75ca609b80e078fe927c5dae53c8754caa3ae1821ea7537e7337126ff4cd
Tag and push image to registry.
$ docker tag ubuntu_nc localhost:5000/org_name/ubuntu_nc:v1.0
$ docker push localhost:5000/org_name/ubuntu_nc:v1.0
The push refers to repository [localhost:5000/org_name/ubuntu_nc]
a8de0e025d94: Pushed
a5e66470b281: Pushed
ac7299292f8b: Pushed
e1a9a6284d0d: Pushed
fccbfa2912f0: Pushed
v1.0: digest: sha256:7d80d9e150e49fd4646b9b9a16ea135b27466b9611df685c4479aafed700ea3a size: 1357
save and load helps you in transferring images offline.
$ docker save -o docker_images.tgz ubuntu:16.04 debian
$ docker load -i docker_images.tgz
e1df5dc88d2c: Loading layer [==================================================>] 105.1MB/105.1MB
Loaded image: debian:latest
Loaded image: debian:prod
fccbfa2912f0: Loading layer [==================================================>] 116.9MB/116.9MB
e1a9a6284d0d: Loading layer [==================================================>] 15.87kB/15.87kB
ac7299292f8b: Loading layer [==================================================>] 14.85kB/14.85kB
a5e66470b281: Loading layer [==================================================>] 5.632kB/5.632kB
a8de0e025d94: Loading layer [==================================================>] 3.072kB/3.072kB
Loaded image: ubuntu:16.04
roadbodysat-lm:Python gsree$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu 16.04 c9d990395902 7 days ago 113MB
debian latest 2b98c9851a37 5 weeks ago 100MB
debian prod 2b98c9851a37 5 weeks ago 100MB
System cleanup of unused stuff.
$ docker system prune
WARNING! This will remove:
- all stopped containers
- all networks not used by at least one container
- all dangling images
- all build cache
Are you sure you want to continue? [y/N] y
Deleted Containers:
dd5588e2719751085ca1b2ad0cdab20916780249f644745e03fb6a6f5f974d59
86de719ca65973154f0d898d7ad97aa882fcb73dba502bb67b09591c918a3e03
Deleted Networks:
helloservice_webnet
Total reclaimed space: 65B
$
Remove stopped containers.
$ docker rm c3dc43d18170 ffc8d7f40dbf 46d69c4db84c
c3dc43d18170
ffc8d7f40dbf
46d69c4db84c
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
Remove unused images.
$ docker rmi c9d990395902
Untagged: ubuntu:latest
Untagged: ubuntu@sha256:9ee3b83bcaa383e5e3b657f042f4034c92cdd50c03f73166c145c9ceaea9ba7c
Deleted: sha256:c9d990395902a9e219684af847a63d793ccf72cf2aadeece1b576566c5662400
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
$