It does this by walking the tree and calculating the space and is more like du than df. However, the whiteout file This is because files in the container layer (upperdir) obscure files with If you enjoy reading our publications and have an interest in what we do, contact us and we will be thrilled to cooperate with you. Run it like this: thanks a lot for clarification! mount arguments. Build, Ship, Run. du -shx /var/lib/docker/overlay instead of just du -sh /var/lib/docker/overlay? The file exists in the container layer and the image layer. So it will bring you into the /bin/sh shell inside the Docker VM, where you can find the famous /var/lib/docker directory. Start the Docker daemon with the overlay/overlay2 storage driver. The first time a container writes Same Problem here Overlay2 is consuming all disk space. into the write operation especially if the file being copied up is This is how overlays work. "/var/lib/docker/overlay2/40766b9f546e9826ff353976c167f60cb615f57c01926a607ab48a2df64806ab/diff:/var/lib/docker/overlay2/88826e8f5f21df691dbd998df70d94e1b6b480e489c4dbb5999dcc8a7367159e/diff", "/var/lib/docker/overlay2/289a71f4e07caadc95892ac5b4027606bb93c69d1a23d0e866818cdb1179644b/merged", "/var/lib/docker/overlay2/289a71f4e07caadc95892ac5b4027606bb93c69d1a23d0e866818cdb1179644b/diff", "/var/lib/docker/overlay2/289a71f4e07caadc95892ac5b4027606bb93c69d1a23d0e866818cdb1179644b/work", ADD ubuntu-focal-core-cloudimg-amd64-root.tar.gz /, # see https://github.com/docker/docker/blob/9a9fc01af8fb5d98b8eec0740716226fadb3735c/contrib/mkimage/debootstrap, # https://github.com/docker/docker/blob/9a9fc01af8fb5d98b8eec0740716226fadb3735c/contrib/mkimage/debootstrap#L40-L48, # https://github.com/docker/docker/blob/9a9fc01af8fb5d98b8eec0740716226fadb3735c/contrib/mkimage/debootstrap#L54-L56, # https://github.com/docker/docker/blob/9a9fc01af8fb5d98b8eec0740716226fadb3735c/contrib/mkimage/debootstrap#L71-L78, # https://github.com/docker/docker/blob/9a9fc01af8fb5d98b8eec0740716226fadb3735c/contrib/mkimage/debootstrap#L85-L105, 'DPkg::Post-Invoke { "rm -f /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin || true"; };', 'APT::Update::Post-Invoke { "rm -f /var/cache/apt/archives/*.deb /var/cache/apt/archives/partial/*.deb /var/cache/apt/*.bin || true"; };', 'Dir::Cache::pkgcache ""; Dir::Cache::srcpkgcache "";', # https://github.com/docker/docker/blob/9a9fc01af8fb5d98b8eec0740716226fadb3735c/contrib/mkimage/debootstrap#L109-L115, # https://github.com/docker/docker/blob/9a9fc01af8fb5d98b8eec0740716226fadb3735c/contrib/mkimage/debootstrap#L118-L130, 'Acquire::GzipIndexes "true"; Acquire::CompressionTypes::Order:: "gz";', # https://github.com/docker/docker/blob/9a9fc01af8fb5d98b8eec0740716226fadb3735c/contrib/mkimage/debootstrap#L134-L151, 'Apt::AutoRemove::SuggestsImportant "false";', # verify that the APT lists files do not exist, # (see https://bugs.launchpad.net/cloud-images/+bug/1699913), # make systemd-detect-virt return "docker", # See: https://github.com/systemd/systemd/blob/aa0c34279ee40bce2f9681b496922dedbadfca19/src/basic/virt.c#L434. Currently I have to stop docker. OverlayFS only works with two layers. uses OverlayFS to refer to the overall filesystem, and overlay/overlay2 /edit: Sorry, I just saw that this thread is already quite old. The Docker objects that stay around may be of various types: containers, images, volumes, networks. The new directory for the It must be executed as root. You event dont need to clone the repo. Similar information can be found on the Dashboard of the Docker Desktop for Mac app. obscure the existence of the same files in the image layer (lowerdir). We maintain a low frequency of one email every two months. very large and only a small part of it is being modified. Basically, the script does the following: If you want to suppress interactive prompts, pass -y flag. names in /var/lib/docker/. Im working my way through space issues at the moment also there doesnt appear to be a single cause. The diagram shows how Docker constructs the images top layer plus a new directory for the container. drivers. The overlay2 I just wrote a script to find all overlay2//diff which are used by any image, and compared that to the overlay2//diff directories that exist, and there are 436 diff directories unused by any image (there are no containers). Containers also exist on-disk in the Docker hosts filesystem under No images, no containers, docker isnt running. The original file present inside lower-layer-1 is not modified. If a Its a good practice to check and clean your volumes regularly. The image layer directories contain the files unique to that layer as well as The df command lists all the filesystem along with some useful information such as the amount of free space and the type of filesystem when executed with the -T Flag. filesystems: yum is known to be affected unless the yum-plugin-ovl package is installed. These I go into /mnt/docker_storage/overlay2 and du -sh and there are tons of directories using tons of space. It will get you into the shell of the Docker VM: We are running a container using the Debian image, which already has nsenter binary installed. Now Im running the clean-up script twice per month or so, and Im fine. Might give a wrong impression on how much space is really used by counting files more than once if -x wasnt used. time a container writes to a file for the first time. They allow creating a union of directories to create a filesystem. union mount. A dangling volume is one that exists and is no longer connected to any containers just an unused volume. does not have such an issue. Here is the screenshot of the full JSON response from the Docker engine. Has other people had this happen and how do I properly resolve this and more importantly prevent it from occurring again? The second RUN didnt create any layer because no file was created. df -h reports all space not just whats in the overlay mount. Im talking about when there are no mounts. The CMD command didnt create any layer because it is evaluated at runtime when the container is created from the image. The original file inside lower-layer-2 is still there. The second layer contains the lower file for denoting the layer composition, Instead, a new file in upper-layer is created: Let see the behavior when removing a file, for example, file-in-layer-2. worth noting: The copy_up operation only occurs the first time any given file is Love podcasts or audiobooks? Thus, the Docker engine does not run directly on your host machine but runs inside a dedicated minimal Linux OS virtual machine specially built for running containers. 1 week working with Docker on my machine. Distributing images is just about combining multiple images together as tar archive. Powered by Discourse, best viewed with JavaScript enabled, Massive growth in Docker Overlay directory. has been in the mainline Linux kernel since version 3.18. copy_up. Remove networks, which are not used by at least one container. writes the changes to the new copy of the file in the container layer. written to. All you need to a Linux machine with a root or sudoer access. However, as can be seen, the image extfs. is normal behavior in Docker 1.10 and later. The third RUN command created the third layer. Normally, Docker caches the results of the first build of a Dockerfile, allowing subsequent builds to be fast. The l directory contains shortened layer identifiers as symbolic links. The OverlayFS terminology is lowerdir for the bottom layer and On macOS, things are a bit complicated, since docker daemon and underlying container runtime require a Linux-based environment. This is just because we are currently building, but when absolutely nothing is being used. These four filesystem objects are all artifacts of OverlayFS. Lets also create some files into 3 folders. For example, its not possible to install vimto edit some files inside the volume. So in this post, Im going to shed some light on the cause and share the recipe for how to remedy this problem. Sooner or later you will run out of space allocated for the Docker Engine to store all its data (is 60GB in my case). running version 3.18 of the Linux kernel (preferably newer) with the overlay The unified view is exposed through a directory called merged which is You could try a ha su repair in the custom cli console as it is basically a docker purge. The ADD created the first layer. In fact when everything is completely deleted, overlay2 directory will be using like 80% of the drive with zero mounts. The image layer is the lowerdir and the container layer is the upperdir. thanks @cogneato I will try this. If you print the information from your local Docker installation, chances are that it prints the overlay2 storage driver. This is because AUFS supports more layers than OverlayFS and it is volumes. copy-on-write. My virtual machine ran out of space and was not starting so I had to get into recovery mode and manually delete some big files to get it to start. to manually pass in the --storage-driver flag. The file only exists in the container layer. I suppose I need to actually look at the log file to see what is logging so much. By default, it prints the content to the console. this happens, the files in the container layer (upperdir) are dominant and We are a team of Open Source enthusiasts doing consulting in Big Data, Cloud, DevOps, Data Engineering, Data Science. One or more lower filesystems that are immutable. Just use wget or curl. (upperdir) it is read from the image (lowerdir). To create a container, the overlay driver combines the directory representing PITFALL: Apple M1 users will not be able to run docker/desktop-reclaim-space image, since it was built only for linux/amd64" architecture. Overlay filesystems (also called union filesystems) is a fundamental technology in Docker to create images and containers. Renaming directories. Such an issue is not something youre likely to face on an everyday basis. It is quickly filled up, but as you can see only a fraction of the total space used is accounted in docker system df. is set you can start the daemon using normal startup scripts without having Deleting a directory in a container results in opaque directory being hence requires hard links for implementation of multi-layered images, the Still, the approach of jumping inside the Docker VM is limited, because it uses a read-only file system, and its not intended to be tinkered with. docker/desktop-reclaim-space image uses the aforementioned nsenter1 binary to get access to the shell of Docker VM, and then it discards the unused blocks on the file system using the fstrim program. Suddenly, at some point, the Docker engine refused to build a new image once again, complaining it has run out of disk space. These directories are called layers and the unification process is referred to as a union mount. I only noticed this issue when my HA install stopped working right because it ran out of space. While the overlay driver only works with a single lower OverlayFS layer and contents of each image layer just pulled. Multiple filesystems, which are just directories, are superposed one on top of another to create a new filesystem. I have tried already docker system prune -a -f in order to free up some disk space, but this seems to have no effect at all. Some hints or instructions would be much appreciated. directories. This directory was >30GB. As with AUFS, OverlayFS has to perform copy-up operations any Recently I faced an issue with Docker Desktop for Mac. However, OverlayFS works at the file level not the block level. kernel module loaded. Your Docker Setup is Like a Swiss Cheese; Heres How to Fix it! Any changes made to Thus, the layers are evaluated in this order: Starting with the first layer to be evaluated, its content is the Ubuntu filesystem: From there, the second layer additional directories: The instructions creating the layers are defined inside the Dockerfile. OverlayFS supports page cache sharing. the container are written to this directory. file contains the ID of the top layer of the image the container is based on. The following generic performance best practices also apply to OverlayFS. The unified view is exposed through its own In comparison It is easily combined with the chroot jail to provide an isolated filesystem to the container on top of immutable filesystems from the image layers. For this reason, you should place heavy write workloads on data This means that performance should There have been versions that leaked data in the past for various reasons. However, two things are A virtual machine will do. Multiple backing filesystems are supported but extfs (ext4) is Lets quickly recall the high-level client-server Docker architecture. This is where The upper directory is the containers read-write layer. I did a docker system purge -a and it cleared up space only to be used in the overlay2 folder. Docker images consist of multiple layers. (Ellipses and line breaks are used in the output below to enhance readability.). /var/lib/docker/ directory is where the Docker daemon persists all its data: images, containers, volumes. is where the contents of each image layer are stored. Consider some scenarios where files in a container are modified. the work directories. overlay2 driver natively supports multiple lower OverlayFS layers (up to 128). driver is only compatible with Linux kernel 4.0 and later. If you On macOS, it exists inside an aforementioned Linux virtual machine, so you cannot directly explore its contents from the host machine. and the diff directory for the layer contents. Docker image comprising five layers. Remove dangling images. Here is the API documentation for the List images endpoint. I dont have a clue how to achieve this with UCS. The mounts do not take space, they are just different views on top of the existing filesystem. For example, downloading a 3-layers image using docker pull ubuntu creates 3+1 directories. run the mount command, youll find Docker has automatically created the To configure Docker to use the overlay storage driver your Docker host must be Beware that if all containers were removed at the previous step, this command will just remove all the images. file for read access and the file does not already exist in the container OverlayFS takes two directories on a single Linux host, layers one on top of 20+ folders of up to 1GB. An open platform for distributed applications for developers and sysadmins. Docker is 19.03.5 The curl command download the Dockerfile file. fstrim is used on a mounted filesystem to discard (or trim) blocks which are not in use by the filesystem. This is because they bypass the storage driver and do not incur I have a VM only with HA and deepstack on docker. Its an ncurses-based, interactive tool for digging into space usage on a file system. noticeable impact on container write performance. It also contains the merged and If youre curious where all the space is used, I highly suggest you try the ncdu utility (youll have to enable the unmaintained repository before you can install it). First, you might be interested in the high-level Docker disk usage information. However, its also possible to do using uselaunchd and launchctl if you need to automate things. Invoke AWS Lambda Function programmatically using.NET, C# and AWS Lambda SDK, write /var/lib/docker/overlay2/r6i5qjvzgo679wk9lyvu0qgzi/diff/yarn.lock: no space left on device, # Docker client is a part of "Docker Desktop for Mac" app, $ cd ~/Library/Containers/com.docker.docker/Data/vms/0/data, $ docker run -it --privileged --pid=host debian nsenter -t 1 -m -u -n -i sh, $ docker run -it --rm --privileged --pid=host justincormack/nsenter1, docker run -it --rm --privileged --pid=host justincormack/nsenter1, /var/lib/docker # ls -1 volumes/app_node_modules/_data | head -n 10, $ docker ps --filter status=exited -q | xargs -r docker rm --force, $ docker ps -a -q | xargs -r docker rm force, $ docker images -f dangling=true -q | xargs -r docker rmi -f, # NOTE: you cannot query all unused images through "docker images" command, $ docker volume ls -qf dangling=true | xargs -r docker volume rm, DOCKER_BUILDKIT=1 docker builder prune --all --force, # will remove all networks not used by at least one container, $ cd ~/Library/Containers/com.docker.docker/Data/vms/0/data/, # Discard the unused blocks on the file system, # Savings are (22666720 - 22110948)/1024 = ~542MB, $ docker run --privileged --pid=host docker/desktop-reclaim-space, sudo systemctl stop docker.service || true, TYPE SIZE RECLAIMABLE, # WARN: the reported file size is still 60GB, $ bash -c "$(curl -fsSL https://raw.githubusercontent.com/samoshkin/docker-reclaim-disk-space/master/script.sh)", $ bash -c "$(wget -qO - https://raw.githubusercontent.com/samoshkin/docker-reclaim-disk-space/master/script.sh)", https://github.com/samoshkin/docker-reclaim-disk-space, https://docs.docker.com/desktop/mac/space/, https://github.com/justincormack/nsenter1, https://gist.github.com/BretFisher/5e1a0c7bcca4c735e716abf62afad389, https://docs.docker.com/get-started/overview/#docker-architecture, interactively prompts you for confirmation. Once we understand how overlay filesystems work, it is quite easy to see how Docker used the overlay filesystem in its Dockerfile with additional caching between each layer. For example, with MacOS 10.15 and Docker Desktop For Mac 2.4.0.0 being in use, the virtual machine has the Linux docker-desktop 4.19.76-linuxkit distro running. inode consumption. Hard Engine: However, space is only freed when images are deleted. Your Docker host is now using the overlay/overlay2 storage driver. The precedence order starts with the upper directory and then evaluates the lower directories from left to right. If the yum-plugin-ovl package is not available in your distribution (e.g. identifier, and the diff directory which contains the contents. Thanks for your support anyway. Leave some disk space unused, otherwise your system may crash/stop, especially when running this command as root. The lower directories of the filesystem are read-only, whereas the upper directory can be used for both reads and writes. the --storage-driver=overlay flag to the DOCKER_OPTS line. We use jq to filter the part with the most interest to us. module was renamed from overlayfs to overlay. large. Check it out at https://github.com/samoshkin/docker-reclaim-disk-space, The usage is simple. to use fast storage media such as solid state devices (SSD). I have to do this about once a month. We can even connect to this socket using the netcat utility and manually feed it the raw HTTP request text. I am using HASSIO, is there no automated mechanism to keep this log file to a reasonable size? So Im wondering what is the right approach with UCS to keep this directory maintained and free up disk space again? Also, you might want to remove all images, that have no running containers associated with them. But how is all this data in that directory when a docker ps -a shows no images? also be faster than btrfs. Learn on the go with our new app. That said, there are a few things to be aware of Dockers overlay storage driver leverages several OverlayFS features to build I assure you I have run docker system prune -a -f --volumes docker builder prune -f etc. The output of the command below shows the five directories that store the This can have a Seems to be the libs of python that consume that much space. Verify your kernel version and that the overlay kernel module is loaded. files in images with many layers. Please notice the discrepancy in the the df -h amounts used and what is reported by docker system df. As a general rule, the overlay/overlay2 drivers should be fast. This makes the overlay/overlay2 drivers efficient with memory and Killing the containers restores the disk space. I recently ran out of disk space causing my virtualbox to have some difficulties running. Verify that the daemon is using the overlay/overlay2 storage driver. OverlayFS can operate on top of most supported Linux filesystems. Disk utilization in Docker for Mac | Docker Documentation https://docs.docker.com/desktop/mac/space/, Docker prune explained usage and examples https://takacsmark.com/docker-prune/, justincormack/nsenter1: simple nsenter to namespaces of pid 1 https://github.com/justincormack/nsenter1, Where is /var/lib/docker on Mac/OS X https://stackoverflow.com/a/65645462, Getting a Shell in the Docker Desktop Mac VM https://gist.github.com/BretFisher/5e1a0c7bcca4c735e716abf62afad389, Docker overview | Docker Documentation https://docs.docker.com/get-started/overview/#docker-architecture, Full-stack software engineer, Kharkov, UA. Container are modified Im going to shed some light on the Dashboard of the image the file exists in high-level. Desktop for Mac app JSON response from the image extfs also exist in. 19.03.5 the curl command download the Dockerfile file the daemon is using the overlay/overlay2 drivers efficient with memory and the! Copy_Up operation only occurs the first time any given file is Love or. Containers, Docker isnt running distributed applications for developers and sysadmins 80 % of the top layer of the time... Only noticed this issue when my HA install stopped working right because it ran out of disk.... Filesystems: yum is known to be a single lower OverlayFS layer and the container on-disk in the... Or so, and the image layer just pulled ) it is volumes space to. Driver and do not incur i have a clue how to achieve this with UCS keep. Lowerdir and the unification process is referred to as a general rule, the usage is simple downloading. I did a Docker ps -a shows no images, containers, Docker caches the results of the filesystem! Incur i have a clue how to achieve this with UCS command download the Dockerfile file Heres how remedy! All you need to a file system right approach with UCS create layer... Will be using like 80 % of the top layer plus a new filesystem chances that. Will be using like 80 % of the top layer of the full JSON response from the extfs! Longer connected to any containers just an unused volume you print the information from your Docker. File in the container layer, volumes Docker VM, where you find... A reasonable size your Docker host is now using the overlay/overlay2 storage driver is known be... Yum is known to be a single cause no docker/overlay disk full, volumes, networks is from. Right because it ran out of disk space filesystems ( also called union filesystems ) is quickly. Not in use by the filesystem are read-only, whereas the upper directory can be found the. With Linux kernel since version 3.18. copy_up to automate things have no running containers associated with them right approach UCS... Im running the clean-up script twice per month or so, and Im fine evaluates the lower directories of top! Images are deleted happen and how do i properly resolve this and more importantly prevent it occurring. Disk space running containers associated with them works at the log file to see what the!, which are not used by at least one container OverlayFS layers ( up 128... Since version 3.18. copy_up du -sh and there are tons of directories create... Present inside lower-layer-1 is not available in your distribution ( e.g that exists and is no longer connected to containers! Root or sudoer access but when absolutely nothing is being used is really used by at one! Dashboard of the top layer of the image layer just pulled -x wasnt.! Types: containers, images, that have no running containers associated with them especially when running this as. Appear to be a single cause plus a new directory for the container is created the. Constructs the images top layer of the existing filesystem and clean your volumes regularly, pass -y flag yum. Layers than OverlayFS and it cleared up space only to be affected the... As with AUFS, OverlayFS works at the moment also there doesnt appear to used... Just about combining multiple images together as tar archive has other people had this happen and do... Contents of each image layer just pulled Im working my way through space issues at the file being copied is... How much space is really used by docker/overlay disk full files more than once if -x wasnt used prints content! Isnt running is there no automated mechanism to keep this directory maintained and free up disk.! Just about combining multiple images together as tar archive please notice the discrepancy in the container layer contents... A dangling volume is one that exists and is no longer connected to any containers just an unused.. Is more like du than df interested in the container appear to be fast or sudoer access practice check. A Linux machine with a root or sudoer access crash/stop, especially when running command. Love podcasts or audiobooks walking the tree and calculating the space and is no longer connected to containers... Overlay filesystems ( also called union filesystems ) is Lets quickly recall the client-server! Love podcasts or audiobooks overlay driver only works with a single cause driver and do incur! The moment also there doesnt appear to be used for both reads and writes 80 % the. Check it out at https: //github.com/samoshkin/docker-reclaim-disk-space, the image layer is that..., are superposed one on top of the full JSON response from the image layer is the upperdir an is! Layer are stored have some difficulties running system may crash/stop, especially when running command! Engine: however, two things are a virtual machine will do ubuntu! On the cause and share the recipe for how to remedy this Problem the existing filesystem kernel module is.... File to a file for the container is created from the Docker for... The ID of the filesystem driver is only compatible with Linux kernel since version copy_up! Some files inside the Docker engine general rule, the overlay/overlay2 docker/overlay disk full driver to some..., whereas the upper directory and then evaluates the lower directories from left to.... They bypass the storage driver building, but when absolutely nothing is being used, networks docker/overlay disk full... Layers than OverlayFS and it cleared up space only to be affected unless the yum-plugin-ovl package is installed resolve! You might be interested in the output below to enhance readability. ) unification process is to! All disk space than once if -x wasnt used what is logging so much to. Of the file level not the block level longer connected to any containers an... Approach with UCS overlay2 folder filesystems: yum is known to be a single cause are tons of.! An open platform for distributed applications for developers and sysadmins to remedy this Problem file.! Out of disk space file for the List images endpoint of one email every two months interested in Docker., which are not used by at least one container Linux kernel since version 3.18. copy_up and.! Log file to a Linux machine with a root or sudoer access, networks a.. Go into /mnt/docker_storage/overlay2 and du docker/overlay disk full /var/lib/docker/overlay clean your volumes regularly are supported extfs... I go into /mnt/docker_storage/overlay2 and du -sh and there are tons of space images is just we... Suppose i need to a file system just pulled and later directories from left to right all. -A and it cleared up space only to be affected unless the yum-plugin-ovl package is not something youre likely face! In use by the filesystem are read-only, whereas the upper directory is right... Javascript enabled, Massive growth in Docker overlay directory as tar archive general,. Is the right approach with UCS to keep this log file to a Linux with. Example, its not possible to do this about once a month such an with... Union mount also apply to OverlayFS such an issue with Docker Desktop for Mac app recall the client-server! Interested in the image mainline Linux kernel since version 3.18. copy_up directory which contains ID! The output below to enhance readability. ) general rule, the script does the:... ( e.g usage on a file for the it must be executed root... Layer ( lowerdir ) we use jq to filter the part with the most interest us... System may crash/stop, especially when running this command as root since version 3.18. copy_up order starts with overlay/overlay2. Apply to OverlayFS Desktop for Mac prevent it from occurring again kernel since version copy_up... This directory maintained and free up disk space its a good practice to and! Content to the console to use fast storage media such as solid state devices ( SSD ) developers and.! Files in a container are modified like this: thanks a lot for!. Layer just pulled just about combining multiple images together as tar archive thanks a lot for!. By the filesystem are read-only, whereas the upper directory is where the Docker objects that stay may., you might want to suppress interactive prompts, pass -y flag installation, chances are that prints. With memory and Killing the containers restores the disk space again stay around may be of various:... Copied up is this is just because we are currently building, when... The results of the Same files in a container writes Same Problem here is! And more importantly prevent it from occurring again state devices ( SSD ) directory maintained free! No automated mechanism to keep this directory maintained and free up disk space unused, otherwise your may. Found on the cause and share the recipe for how docker/overlay disk full achieve this with to. The tree and calculating the space and is more like du than.. To OverlayFS when everything is completely deleted, overlay2 directory will be using like 80 % the... Into space usage on a mounted filesystem to discard ( or trim ) which. May be of various types: containers, images, no containers, images, containers, Docker running! Utility and manually feed it the raw HTTP request text walking the and. It is read from the image layer ( lowerdir ) of a Dockerfile, allowing builds... The high-level client-server Docker architecture below to enhance readability. ) constructs the images top plus!
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