weixin_39865440
weixin_39865440
2021-01-09 08:13

Allow specifying the arch of the image to pull

Description

Add a flag to buildah from/buildah pull to select the arch of the tag to pull.

This is useful to manipulate cross-platform containers (eg, aarch64 on amd64), either for builds that don't use buildah run or by also setting up qemu+binfmt.

Output of rpm -q buildah or apt list buildah:


🐚 apt list buildah                                                                                              
Listing... Done
buildah/unknown,now 1.14.9~1 amd64 [installed]
buildah/unknown 1.14.9~1 arm64
buildah/unknown 1.14.9~1 armhf
buildah/testing 1.11.6-1 i386
buildah/unknown 1.14.9~1 ppc64el

Output of buildah version:


Version:         1.14.9
Go Version:      go1.14.2
Image Spec:      1.0.1-dev
Runtime Spec:    1.0.1-dev
CNI Spec:        0.4.0
libcni Version:  
image Version:   5.4.3
Git Commit:      
Built:           Sun May 17 12:12:33 2020
OS/Arch:         linux/amd64

Output of cat /etc/*release:


🐚 cat /etc/*release                                                                                             
PRETTY_NAME="Debian GNU/Linux bullseye/sid"
NAME="Debian GNU/Linux"
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"

Output of uname -a:


(paste your output here)

Output of cat /etc/containers/storage.conf:


# This file is is the configuration file for all tools
# that use the containers/storage library.
# See man 5 containers-storage.conf for more information
# The "container storage" table contains all of the server options.
[storage]

# Default Storage Driver
driver = ""

# Temporary storage location
runroot = "/var/run/containers/storage"

# Primary Read/Write location of container storage
graphroot = "/var/lib/containers/storage"

# Storage path for rootless users
#
# rootless_storage_path = "$HOME/.local/share/containers/storage"

[storage.options]
# Storage options to be passed to underlying storage drivers

# AdditionalImageStores is used to pass paths to additional Read/Only image stores
# Must be comma separated list.
additionalimagestores = [
]

# Remap-UIDs/GIDs is the mapping from UIDs/GIDs as they should appear inside of
# a container, to the UIDs/GIDs as they should appear outside of the container,
# and the length of the range of UIDs/GIDs.  Additional mapped sets can be
# listed and will be heeded by libraries, but there are limits to the number of
# mappings which the kernel will allow when you later attempt to run a
# container.
#
# remap-uids = 0:1668442479:65536
# remap-gids = 0:1668442479:65536

# Remap-User/Group is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid or /etc/subgid file.  Mappings are set up starting
# with an in-container ID of 0 and then a host-level ID taken from the lowest
# range that matches the specified name, and using the length of that range.
# Additional ranges are then assigned, using the ranges which specify the
# lowest host-level IDs first, to the lowest not-yet-mapped in-container ID,
# until all of the entries have been used for maps.
#
# remap-user = "containers"
# remap-group = "containers"

# Root-auto-userns-user is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid and /etc/subgid file.  These ranges will be partioned
# to containers configured to create automatically a user namespace.  Containers
# configured to automatically create a user namespace can still overlap with containers
# having an explicit mapping set.
# This setting is ignored when running as rootless.
# root-auto-userns-user = "storage"
#
# Auto-userns-min-size is the minimum size for a user namespace created automatically.
# auto-userns-min-size=1024
#
# Auto-userns-max-size is the minimum size for a user namespace created automatically.
# auto-userns-max-size=65536

[storage.options.overlay]
# ignore_chown_errors can be set to allow a non privileged user running with
# a single UID within a user namespace to run containers. The user can pull
# and use any image even those with multiple uids.  Note multiple UIDs will be
# squashed down to the default uid in the container.  These images will have no
# separation between the users in the container. Only supported for the overlay
# and vfs drivers.
#ignore_chown_errors = false

# Path to an helper program to use for mounting the file system instead of mounting it
# directly.
#mount_program = "/usr/bin/fuse-overlayfs"

# mountopt specifies comma separated list of extra mount options
mountopt = "nodev"

# Size is used to set a maximum size of the container image.
# size = ""

[storage.options.thinpool]
# Storage Options for thinpool

# autoextend_percent determines the amount by which pool needs to be
# grown. This is specified in terms of % of pool size. So a value of 20 means
# that when threshold is hit, pool will be grown by 20% of existing
# pool size.
# autoextend_percent = "20"

# autoextend_threshold determines the pool extension threshold in terms
# of percentage of pool size. For example, if threshold is 60, that means when
# pool is 60% full, threshold has been hit.
# autoextend_threshold = "80"

# basesize specifies the size to use when creating the base device, which
# limits the size of images and containers.
# basesize = "10G"

# blocksize specifies a custom blocksize to use for the thin pool.
# blocksize="64k"

# directlvm_device specifies a custom block storage device to use for the
# thin pool. Required if you setup devicemapper.
# directlvm_device = ""

# directlvm_device_force wipes device even if device already has a filesystem.
# directlvm_device_force = "True"

# fs specifies the filesystem type to use for the base device.
# fs="xfs"

# log_level sets the log level of devicemapper.
# 0: LogLevelSuppress 0 (Default)
# 2: LogLevelFatal
# 3: LogLevelErr
# 4: LogLevelWarn
# 5: LogLevelNotice
# 6: LogLevelInfo
# 7: LogLevelDebug
# log_level = "7"

# min_free_space specifies the min free space percent in a thin pool require for
# new device creation to succeed. Valid values are from 0% - 99%.
# Value 0% disables
# min_free_space = "10%"

# mkfsarg specifies extra mkfs arguments to be used when creating the base
# device.
# mkfsarg = ""

# Size is used to set a maximum size of the container image.
# size = ""

# use_deferred_removal marks devicemapper block device for deferred removal.
# If the thinpool is in use when the driver attempts to remove it, the driver
# tells the kernel to remove it as soon as possible. Note this does not free
# up the disk space, use deferred deletion to fully remove the thinpool.
# use_deferred_removal = "True"

# use_deferred_deletion marks thinpool device for deferred deletion.
# If the device is busy when the driver attempts to delete it, the driver
# will attempt to delete device every 30 seconds until successful.
# If the program using the driver exits, the driver will continue attempting
# to cleanup the next time the driver is used. Deferred deletion permanently
# deletes the device and all data stored in device will be lost.
# use_deferred_deletion = "True"

# xfs_nospace_max_retries specifies the maximum number of retries XFS should
# attempt to complete IO when ENOSPC (no space) error is returned by
# underlying storage device.
# xfs_nospace_max_retries = "0"

该提问来源于开源项目:containers/buildah

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9条回答

  • weixin_39945816 weixin_39945816 4月前

    Hi ,

    this is already supported via $ buildah pull --override-arch=arm. However, the flag is hidden and I don't quite understand the reasoning for that.

    PTAL

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  • weixin_39998795 weixin_39998795 4月前

    Mainly, that there could be some bugs there.

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  • weixin_39961943 weixin_39961943 4月前

    I think we should expose it and document it. Although I would prefer the flag to be --arch.

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  • weixin_39865440 weixin_39865440 4月前

    Also maybe add the same flag to from? If you have multiple images with the same tag but different arches, querying for the right one will be annoying. (Or however it works? Tbh I don't really fully understand how multi-image tags work.)

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  • weixin_39998795 weixin_39998795 4月前

    Image names aren't related to the architecture of the images, and there should only ever be one image with a given name in local storage. If an image's name is specified as a base for a working container or for a Dockerfile-based build, we don't mind if the image we have with that name is for a non-default architecture, and I could see the result of that being surprising.

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  • weixin_39540315 weixin_39540315 4月前

    Any news on this? I'm creating multiarch images in a loop and the only known way to do that right now (assuming my builds are bases on another multiarch manifest) is this:

    buildah rmi --all --force IMAGE_ID=$(buildah pull --override-arch=$BUILDARCH alpine:latest) container=$(buildah from $IMAGE_ID) buildah config --arch $BUILDARCH $container

    The --arch $BUILDARCH actually does nothing as the wrong image would already have been pulled/reused. The --override-arch=$BUILDARCH also does nothing if there is already another arch downloaded

    So the only way this is working at all is to purge everything with buildah rmi --all --force

    Deleting all local containers so that I no longer have a name clash and buildah is still using the old image (despite using --override-arch) is more than a hack.

    I could reference different tags like alpine:arm64 or so but not all images have different tags for multiple archs and also that would be hard to automate.

    I would need something like --force-redownload and --store-with-different-name-or-id or something like that.

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  • weixin_39865440 weixin_39865440 4月前

    Image names aren't related to the architecture of the images, and there should only ever be one image with a given name in local storage. If an image's name is specified as a base for a working container or for a Dockerfile-based build, we don't mind if the image we have with that name is for a non-default architecture, and I could see the result of that being surprising.

    aiui, most container clients won't pull non-compatible images unless specifically told to.

    I think generally, those of us doing multi-arch shenanigans don't mind passing in the extra arg to pull and from.

    We just want the flag so we can more predictably and easily get the image we're looking for.

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  • weixin_39961943 weixin_39961943 4月前

    PTAL

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  • weixin_39922929 weixin_39922929 4月前

    buildah rmi --all --force IMAGE_ID=$(buildah pull --override-arch=$BUILDARCH alpine:latest) … The --override-arch=$BUILDARCH also does nothing if there is already another arch downloaded

    I guess we are recording the manifest-list RepoTag/RepoDigest value, and detecting that a local image matching that is already present? It is a bug, but it’s also a fairly obscure corner case, and it would require changing the image store. I’m afraid I’m still not intimately familiar with the manifest list copy code… one of these years with nothing to do…

    I would need something like --force-redownload and --store-with-different-name-or-id or something like that.

    I’d expect some kind of buildah rmi to allow untagging the relevant images individually, although that might require extra logic to determine the right digest values.

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