$ sudo systemctl start docker
Configuration
I am on a low bandwith thing, so needed to add max-concurrent-uploads to the /etc/docket/daemon.json, otherwise I got connection timeouts. (default is 5)
{
"experimental": false,
"max-concurrent-uploads": 1,
"data-root": "/mnt/docker"
}
I've since moved the docker data directory ("data-root") to a separate mount ("/mnt/docker"), as it takes up a deal of space.
See reference 1.
Basics
- docker pull dockerimageurl
- downloads a particular image, probably from Docker Hub
- docker images
- can show you all the images the docker has at its disposal
- docker container create
- creates a new container based on an image
- docker run --rm -i -t -p portext:portint dockerimageurl
- start running a new container (-d is detached, -p is portmap, -i keep STDIN open even if not attached , -t allocates a pseudo-TTY, --rm removes container on exit
), basically does all of the previous steps if necessary
Administration
- docker inspect dockerimageurl
- shows low level information on the running container
- docker exec <container-id> cat /data.txt
- run a single command on the container, can be run as long as the master process (pid 1) is running
- docker ls [-a]
- seems to be exactly the same as ps
- docker ps [-a]
- list docker containers (-a for aboth started and stopped)
- docker attach <the-container-id>
- stttach to a running docker container with the ID from docker ps. Convenient if you've run it "detatched".
- docker stop <the-container-id>
- stop docker container with the ID from docker ps
- docker rm <the-container-id>
- remove docker container
- docker rmi <the-image-id>
- removes an image
Examples
Simply running an image can be done with:
docker run --rm -i -t -p 80:8080 -p 443:8181 --name jelasticgraaljdk17 jelastic/javaengine:graalvm-21.0.0.2
"--name" is a nice option to prevent docker from assigning meaningless auto-generated names to your containers.
It will help tremendously if we could look at how an original image was made. This is possible with the history command.
docker history jelastic/javaengine:graalvm-21.0.0.2
Add --no-trunc to show entire command lines.
For example in the example, it will show the following:
| IMAGE | CREATED | CREATED BY | SIZE |
|---|
| 72627645230f | 12 days ago | | 24.4MB |
| <missing> | 12 days ago | /bin/sh -c #(nop) WORKDIR /etc/init.d | 0B |
| <missing> | 12 days ago | /bin/sh -c #(nop) LABEL actions=webAccess a… | 0B |
| <missing> | 12 days ago | /bin/sh -c #(nop) EXPOSE 21 22 25 80 8080 | 0B |
Added 443 8743 to the exposed ports in my new image.
Creating your own image
- docker build
- build a new container image based on a Dockerfile. (-t is tag)
- docker commit c16378f943fe rhel-httpd:latest
- docker login -u YOUR-USER-NAME
- logging into the Docker hub
- docker tag c16378f943fe YOUR-USER-NAME/name
- tag your image appropriately before pushing it to the repo
- docker push imagename:tag
- pushes an image to a remote Docker repository. If you do not provide a tag, it will automatically become "latest".
Examples
cd ../graalvm
docker build -t maartenl22/jelasticgraaljdk11:latest -t maartenl22/jelasticgraaljdk11:v0.1 .
cd ../karchan
docker build -t maartenl22/karchan:latest -t maartenl22/karchan:v2.0.8 .
Check that this worked by running:
docker run --name graalvm --rm -i -t -p 8080:8080 -p 8743:8743 maartenl22/jelasticgraaljdk11:latest
docker run --name karchan --rm -i -t -p 8080:8080 -p 8743:8743 maartenl22/karchan:latest
Pushing your image to Docker Hub
Examples
docker build -t maartenl22/jelasticgraaljdk11 .
docker build -t maartenl22/karchan .
docker image ls
First do this, just to make sure:
docker logout
docker login
docker push maartenl22/jelasticgraaljdk11
docker push maartenl22/karchan
You should see both jelasticgraaljdk11 and registry-host:5000/maartenl22/jelasticgraaljdk11 listed.
You should see both karchan and registry-host:5000/maartenl22/karchan listed.
docker run --name karchan -cap-add=NET_ADMIN --rm -i -t -p 8080:8080 -p 8743:8743 jelasticgraaljdk11:latest
The -cap-add=NET_ADMIN is necessary to see the iptables configuration.
cd /home/jelastic
java -jar payara-micro-5.2021.1.jar --port 80 --sslport 443 jakartaee-8-project.war
Portainer
Portainer is a docker image containing a simple server that interfaces with the Docker deamon. With it you can get a good view of what Docker is running and what containers and images are available and all that.
Also attaching a terminal via de website is possible. Very nice.
docker volume create portainer_dataa
docker run -d -p 8000:8000 -p 9000:9000 --name=portainer --restart=always -v /var/run/docker.sock:/var/run/docker.sock -v portainer_dataa:/data portainer/portainer-ce
When starting it for the first time, and surfing to localhost:9000, you can add an administrator user.
It works great to get a good overview about what's going on.
Hello, world.
References
- [1] GuguWeb - HOW TO MOVE DOCKER DATA DIRECTORY TO ANOTHER LOCATION ON UBUNTU
- https://www.guguweb.com/2019/02/07/how-to-move-docker-data-directory-to-another-location-on-ubuntu/
- Jelastic - Build software stack container image for private PaaS
- https://jelastic.com/blog/build-software-stack-container-image-private-paas/
- Jelastic - Building custom containers
- https://docs.jelastic.com/building-custom-container/
- Docker - Custom container deployment
- https://docs.jelastic.com/custom-containers-deployment/
- Docker - Installing fedora
- https://docs.docker.com/engine/install/fedora/
- Docker - Reference manuals
- https://docs.docker.com/reference/
- Portainer
- https://www.portainer.io/
- Youtube - Intro to Docker [with Java Examples]
- https://youtu.be/FzwIs2jMESM
- Dockerhub - my jelastic graal with jdk 11 docker image
- https://hub.docker.com/r/maartenl22/jelasticgraaljdk11
- Github - Docker file
- https://github.com/maartenl/jelasticgraaljdk11
