A container is a runtime instance of an image.
docker info | grep -i rootcommand to findout:
CMD ["executable","param1","param2"](exec form, this is the preferred form)
CMD ["param1","param2"](as default parameters to ENTRYPOINT)
CMD command param1 param2(shell form)
CMDinstruction in a
Dockerfile. If you list more than one
CMDthen only the last
CMDwill take effect.
.as the build context which means the current directory. If you put the Dockerfile inside another directory like /src/Dockerfile, then the context will be
./src. The build process may take some time to finish:
Successfully built fc32da11d651at the end. This random string is the image id and not container id. try
docker image inspect <image id>to get information about this image , also to see layers which our image includes try
docker image history <image id>:
docker imageswhich is deprecated somehow.
docker pull :
docker imagescommand to locate the ID of the images you want to remove. When you’ve located the images you want to delete, you can pass their ID or tag to
-fwith a value of
docker imagescommand. When you’re sure you want to delete them, you can use the
docker images purgecommand:
docker image prune -awill remove all images with out at least one container associate with them, the good news about this is that if you have images that are being used by containers those images won't be deleted.
f1477ec11d12. It’s just a way of referring to your image. A good analogy is how Git tags refer to a particular commit in your history.
.at the end does). Next, we tell the Docker daemon to build the image and give it the specified tag.
If you need to push your image to a registry use
docker build -t username/image_name:tag_name .:[[email protected]arth sandbox]# docker build -t borosan/myapp:final .Sending build context to Docker daemon 14.85kBStep 1/3 : FROM ubuntu---> adafef2e596eStep 2/3 : LABEL Description="test image" Vendor="ACME Products"---> Using cache---> bdeb04e9a931Step 3/3 : RUN apt-get update && apt-get install -y nginx openssh-server---> Using cache---> fc32da11d651Successfully built fc32da11d651Successfully tagged borosan/myapp:finalREPOSITORY TAG IMAGE ID CREATED SIZEborosan/myapp final fc32da11d651 23 minutes ago 233MBmyapp final fc32da11d651 23 minutes ago 233MBredis latest 50541622f4f1 4 days ago 104MBubuntu latest adafef2e596e 2 weeks ago 73.9MBnginx latest 9beeba249f3e 2 months ago 127MBhello-world latest bf756fb1ae65 6 months ago 13.3kB
TARGET_IMAGEthat refers to the
SOURCE_IMAGE.That’s all it does. It’s like assigning an existing image another name to refer to it. Notice how the tag is specified as optional here as well, by the
docker login localhost:5000.
docker searchcommand does for us:
--limitflag limits the maximum number of results returned by a search.
docker savecommand. For example, lets save a local copy of the
myappdocker image we made: