buildah: podman build tags images in the local registry with a leading localhost/ and docker does not

Description

Does podman build have the goal of being a drop-in replacement for docker? If not, feel free to close this issue. If so, the issue is that podman build -t bodhi-ci/f27 tags the resulting image into the local engine with a leading localhost/ in the repository name, and docker does not do this. This results in a difference in how the image must be referenced later when running docker/podman run, because docker run… bodhi-ci/f27 will work, but podman run… bodhi-ci/f27 will not work (and will try to find that image in a variety of external registries).

Steps to reproduce the issue:

1. Build a Dockerfile with podman and docker, and use the -t flag.
2. For example, I’ve built my Bodhi CI images with -t bodhi-ci/f27 in the examples shown below.

Describe the results you received:

$ sudo docker images
REPOSITORY                          TAG                 IMAGE ID            CREATED             SIZE
bodhi-ci/f27                        latest              4668aacb1a2a        11 hours ago        1.29 GB
$ sudo podman images
REPOSITORY                          TAG      IMAGE ID       CREATED          SIZE
localhost/bodhi-ci/f27              latest   351ffa92bc74   2 minutes ago    1.34GB

Describe the results you expected:

$ sudo podman images
REPOSITORY                          TAG      IMAGE ID       CREATED          SIZE
bodhi-ci/f27              latest   351ffa92bc74   2 minutes ago    1.34GB

Output of rpm -q buildah or apt list buildah:

Buildah is not installed, but the text at https://github.com/containers/libpod/issues/new said to file issues with podman build here.

Output of buildah version:

See above.

Output of cat /etc/*release:

$ cat /etc/redhat-release 
Fedora release 30 (Rawhide)

Output of uname -a:

Linux host.example.com 4.19.0-0.rc3.git3.1.fc30.x86_64 #1 SMP Fri Sep 14 18:31:28 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

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 = "overlay"

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

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

# Size is used to set a maximum size of the container image.  Only supported by
# certain container storage drivers.
size = ""

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

# OverrideKernelCheck tells the driver to ignore kernel checks based on kernel version
override_kernel_check = "true"

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

# Remap-UIDs/GIDs is the mapping from UIDs/GIDs as they should appear inside of
# a container, to 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 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 the 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 container-level ID,
# until all of the entries have been used for maps.
#
# remap-user = "storage"
# remap-group = "storage"

[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 = ""

# 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"

# If specified, use OSTree to deduplicate files with the overlay backend
ostree_repo = ""

# Set to skip a PRIVATE bind mount on the storage home directory.  Only supported by
# certain container storage drivers
skip_mount_home = "false"