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| -rw-r--r-- | docker.html.markdown | 90 |
1 files changed, 89 insertions, 1 deletions
diff --git a/docker.html.markdown b/docker.html.markdown index f69dbddb..e18db5c9 100644 --- a/docker.html.markdown +++ b/docker.html.markdown @@ -187,7 +187,95 @@ $ docker exec -it 7b272 bash # directory. Here 7b272 was our ubuntu container and the above command would
# help us interact with the container by opening a bash session.
-$ docker compose
+$docker logs <container-id>
+# Displays the information logged by the specified container
+# root@7b27222e4bb7:/# whoami
+# root
+# root@7b27222e4bb7:/# pwd
+# /
+# root@7b27222e4bb7:/# ls
+# bin boot dev etc home lib lib32 lib64 libx3 srv sys tmp usr var
+# root@7b27222e4bb7:/# exit
+# exit
# More commands can be found at https://docs.docker.com/engine/reference/commandline/docker/
```
+## The Dockerfile
+The Dockerfile is a blueprint of a Docker image. We can mention the artifacts
+from our application along with their configurations into this file in the
+specific syntax to let anyone create a Docker image of our application.
+
+### A few things to keep in mind:
+* It is always strictly named `Dockerfile` without any extensions
+* We have to build our custom image on top of some already available Docker base
+image. (there is an empty image called `scratch` which literally lets you build
+an image from scratch)
+* All capitalised commands are part of the syntax, they are not case-sensitive
+but used like a convention
+* Below is a sample Dockerfile but you can read in depth from the [official docs](https://docs.docker.com/engine/reference/builder/).
+
+```Dockerfile
+FROM <base-image>
+# define base image
+
+ENV USERNAME='admin'\
+ PWD='****'
+# optionally define environmental variables
+
+RUN apt-get update
+# run linux commands inside container env, does not affect host env
+# This executes during the time of image creation
+
+COPY <src> <target>
+# executes on the host, copies files from src (usually on the host) to target
+# on the container
+
+ENTRYPOINT ["some-script.sh"]
+# executes an entire script as an entrypoint
+
+CMD [<args>,...]
+# always part of dockerfile, introduces entry point linux command e.g.
+# `CMD node server.js`
+# This executes after image creation only when the container from the image
+# is running.
+```
+### Build your images
+Use the `docker build` command after wrapping your application into a Docker
+image to run ( or build) it.
+
+```bash
+
+$docker build <path-to-dockerfile>
+# used to build an image from the specified Dockerfile
+# instead of path we could also specify a URL
+# -t tag is optional and used to name and tag your images for e.g.
+# `$docker build -t my-image:0.1 ./home/app`
+# rebuild images everytime you make changes in the dockerfile
+```
+
+## Push your image to DockerHub
+If you want your application's Docker image to be made publically available for
+any Docker user, you might wanna push it to the [Docker Hub](https://hub.docker.com/) which is a
+registry of Docker images. Make sure you have an account with a username and
+password on Docker Hub.
+
+When pushing an image to Docker Hub, we must specify our Docker Hub username
+as part of the source image name. We need to create the target image with the
+tag name of username/image-name much like GitHub repositories.
+
+```bash
+$docker login
+# to login to Docker Hub using your username and password
+
+$docker tag <src-image>[:<src-tag>] <target-image>[:<target-tag>]
+# this tags a local src-image to a public target-image
+# e.g. `docker tag my-sample-app:1.0.0 akshitadixit/my-sample-app`
+# if tags are not specified, they're defaulted to `latest`
+
+$docker push <target-image>[:<target-tag>]
+# uploads our image to Docker Hub
+# e.g. `docker push akshitadixit/my-sample-app`
+# this image will be accessible under your profile's repositories as
+# `https://hub.docker.com/r/username/image-name`
+
+```
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