Once compiled, these packages are superfluous and should be removed in order to reduce the image size. In some cases images that were more than 1. The following use case does not represent a real world scenario, but provides an example of this use case.
It works to remove a directory when the remove command is defined in the same layer as the creation of the folder:. The problem is that there is not dir in the current directory, because you're already cd ed into it. And since you've added the -f flag, the command doesn't produce an error. This is one of the reasons why you shouldn't use force flags without being very sure you need them. Thus, the next line executes in the original working directory, where it tries to mkdir dir but, as we've previously discussed, that directory still exists with the wgetted contents inside it.
Building on Xiong Chiamiov's answer, which correctly identified the root cause of the problem - the dir reference by relative path when attempting to empty or delete that directory depends on the working directory at the time, which was not correctly set in the cases mentioned in the OP. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. How to remove directories and files in another layer using Docker? Asked 3 years ago.
Active 8 months ago. Viewed 71k times. Why this question?
Sending build context to Docker daemon 1. You most certainly can have multiple RUN statements in your Dockerfile. Check your Dockerfile. Looks like you copy pasted the same line twice.
If you look at step 2 and 3 they are both executing the same code.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
Already on GitHub? Sign in to your account. Unfortunately, the current possibilities for this are suboptimal:. The context contains a lot of directories A A10 and a directory B. A10 have one destination, B has another:. The names A A10, B were fake. There are a couple of options I admit, but I think that all of them are awkward.
I mentioned three in my original posting. A fourth option is to rearrange my source code permanently so that A A10 are moved in a new directory A. I was hoping that this was not necessary because an additional nesting level is not something to wish for, and my current tools needed to special-case my dockerised projects then.
BTW, following symlinks would help in this case. But apparently, this is no option either. Maybe duglin can have a look. I looked and didn't notice some kind of excludes option on 'cp' so I'm not sure how you would solve this outside of a 'docker build' either.
It's still a mild maintenance problem because I would have to think of that line if I added an "A11" directory. But that would be acceptable. Besides, cp does not need excludes, because copying everything and removing the unwanted parts has almost no performance impact beyond the copying itself.
As for doing a RUN rm If you see a cache miss due to it let me know, I don't think you should. It works like rsync with a slash appended to the src directory. Therefore, the four instructions. Fair enough. Thank you for your time! I regularly regret that COPY doesn't mirror rsync's trailing slash semantics.
It means you can't COPY multiple directories in a single statement, leading to layer proliferation. I regularly encounter a case where I want to copy many directories except for one which will be copied later, because I want it to have different layer-invalidation effectsso --exclude would be useful, as well. But I have also encountered this problem in projects that I am not at liberty to rearrange quite so easily.
The main problem is that Go's filepath. Match doesn't allow much creativity compared to regular expressions i.Get the latest tutorials on SysAdmin and open source topics. Write for DigitalOcean You get paid, we donate to tech non-profits.
DigitalOcean Meetups Find and meet other developers in your city. Become an author. In general, Docker containers are ephemeral, running just as long as it takes for the command issued in the container to complete.
By default, any data created inside the container is only available from within the container and only while the container is running. Docker volumes can be used to share files between a host system and the Docker container. Note: Even though the Prerequisites give instructions for installing Docker on Ubuntu Note: The -v flag is very flexible. It can bindmount or name a volume with just a slight adjustment in syntax. You should see:. In this tutorial we demonstrated how to create a Docker data volume to share information between a container and the host file system.
This is helpful in development environments, where it is necessary to have access to logs for debugging. To learn more about sharing persistent data between containers, take a look at How To Share Data between Docker Containers.
Sometimes, however, applications need to share access to data or persist data after a container is deleted. In this article, we'll look at four different ways to share data between containers. Ampache is an open-source music streaming server that allows you to host and manage your digital music collection on your own server. Ampache can stream your music to your computer, smartphone, tablet, or smart TV.
In this tutorial, you will install and configure the Apache webserver and PHP that will serve your Ampache instance. You'll store users and encrypted passwords in the MySQL database and test that you can use those users to log in. The Apache web server uses virtual hosts to manage multiple domains on a single instance. Twitter Facebook Hacker News.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.
If nothing happens, download GitHub Desktop and try again. If nothing happens, download Xcode and try again. If nothing happens, download the GitHub extension for Visual Studio and try again.
Have a copy running in about 30 minutes! This kernel setting needs to be increased on the host or else the Elasticsearch container will refuse to run.
It contains the vital files that Docker will need to get the site running. Run Docker Compose so we can build all the required images, pull the GOG Games website source code and install required dependencies.
Important : Only use letters and numbers for these values. Triple check that you edited these values correctly and remember them as the next steps will require it.
Refer back to config.
Dockerfile: ADD vs COPY
You now need your own. Use Scallion to generate it along with the private key. Continue once have an address and private key. If everything went successfully, you now should be able to visit your copy of GOG Games at your onion address in Tor browser! This is how you resolve it. Copy the ID number of the game. Then go to the admin section of your site and enter the number into the blank box under Add game via Product ID: then click Add.
A popup with the name of the game will appear. Configure a systemd service so the containers thus your site will automatically start on system boot with Docker Compose.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. I find this really useful. You can see some of many usecases clicking at link provided.
As you can see many of subscribers consider it as really useful feature instead of "antipattern". Perhaps I provided wrong link Mainly this will be some combination of host-local and container-contained files. In fact any container can be considered useless without any configuration or initialization.
The problem with this is that it is incredibly short-sighted hence the term "anti-pattern"as it will force you to repeat the operation every time the containers to be recreated. Not to mention the fact that it scales very poorly what if you have 10 containers? The actual solution to your issue is to include those necessary files in your build Dockerfile and rebuild when an update is needed.Docker - Copy files from Container to hostfile
Everything you need is to pull it from repository and mount yes, in this case mount only node-specific config. And even more, you don't need run docker-compose on each node.
Do not ignore .dockerignore (it’s expensive and potentially dangerous)
I'm running into an issue where copy would come in handy at least as an override. I mostly develop on mac so I almost never see an issue with commands running as root in the container and exporting to a mounted volume.
However, recently using the same workflow on a CentOs has caused some major pain because files owned by the root user are being added to the host via the mounted volume.
I would like in these cases to just be able to copy the host files to the container instead of mounting them. The related issue: I think in my case I can get away with using COPY in the Dockerfile and having multiple docker-compose files one of which uses a volume mount.
Use-case: I want to use directory from read-only file system inside container. Application creates new files in that directory, but because filesystem is read only this cause errors. I can't use rw volume, because filesystem is read only. I can't use ro volume, because effect will be the same. It would be awesome to make writes that are persists only when container runs.
Use case: starting multiple docker containers simultaneously from. If the process inside a container fails or if the ci job is cancelled before the container has cleaned up after itself, the remaining files can't be deleted by gitlab-runner due to lack of permissions.
Now I could copy the files within the container out of the volume into another directory, but that would be an antipattern, wouldn't it? Is this different from volumes:. I am able to copy files from host to container equivalent of COPY this way in my compose file.Do you occasionally share your Linux desktop machine with family members, friends or perhaps with colleagues at your workplace, then you have a reason to hide certain private files as well as folders or directories.
The question is how can you do this? To hide a file or directory from the terminal, simply append a dot. Using GUI method, the same idea applies here, just rename the file by adding a. Once you have renamed it, the file will still be seen, move out of the directory and open it again, it will be hidden thereafter. To view hidden files, run the ls command with the -a flag which enables viewing of all files in a directory or -al flag for long listing.
In order to add a little security to your hidden files, you can compress them with a password and then hide them from a GUI file manager as follows. Make use of the feedback form below to share any thoughts with us. TecMint is the fastest growing and most trusted community site for any kind of Linux Articles, Guides and Books on the web. Millions of people visit TecMint!
If you like what you are reading, please consider buying us a coffee or 2 as a token of appreciation. We are thankful for your never ending support. Tags: Linux Tricks. View all Posts. Aaron Kili is a Linux and F. S enthusiast, an upcoming Linux SysAdmin, web developer, and currently a content creator for TecMint who loves working with computers and strongly believes in sharing knowledge. Your name can also be listed here.
Got a tip? Submit it here to become an TecMint author. Hiding files in Linux was not as easy as it looks. I really like your process to delivering that idea. Appending a. And password protecting a compressed file offers minimal security, as they can still read the file, and try to crac it.We work with Dockerfiles on a daily basis; all the code we run for ourselves and for our customers, we run from a set of Dockerfiles.
For those of you who are Docker experts, a lot of the tips in this article will probably be pretty obvious and will just provoke a lot of head-nodding. But for beginner to intermediate developers, this will be a useful guide that will hopefully help clean and speed up your workflow.
Running apt-get install is one of those things virtually every Dockerfile will have. You will probably need to install some external package in order to run your code.
But using apt-get comes with its fair share of gotchas. The first is running apt-get upgrade. This will update all your packages to their latests versions — which is bad because it prevents your Dockerfile from creating consistent, immutable builds. Another issue is with running apt-get update in a different line than running your apt-get install command.
The reason why this is bad is because a line with only apt-get update will get cached by the build and won't actually run every time you need to run apt-get install.
Instead, make sure you run apt-get update in the same line with all the packages to ensure all are updated correctly. The apt-install in the Golang Dockerfile is a good example of how this should be done:. COPY is the simplest of the two, since it just copies a file or a directory from your host to your image. In order to reduce the complexity of your Dockerfile and prevent some unexpected behavior, it's usually best to always use COPY to copy your files.
Being explicit about what part of your code should be included in your build, and at what time, might be the most important thing you can do to significantly speed up your builds. In most cases including the example abovethis means having to re-install our application dependencies.
Doing those two steps before copying over the rest of your application files which should be done at the latest possible line will enable your changes to be quickly re-built. While simple, using the latest tag for an image means that your build can suddenly break if that image gets updated. To prevent this, just make sure you use a specific tag of an image example: node This will ensure your Dockerfile remains immutable.
Many people forget the difference between building a Docker image and running a Docker container.
9 Common Dockerfile Mistakes
When building an image, Docker reads the commands in your Dockerfile and creates an image from it. Your image should be immutable and reusable until any of your dependencies or your code changes. This process should be completely independent of any other container. Anything that requires interaction with other containers or other services like a database should happen when you run the container. An example of this is running a database migration.
Most people attempt to run these when they are building their image. This has a couple of problems. First, the database might not be available during build time, since it might not be built on the same server that it will be running on. If you bust the cache for them, rebuilding them is almost instantaneous.
You should only ever declare ENV s whenever you need them in your build process.