Different behaviour between STORAGE_DRIVER=vfs and --storage-driver=vfs

[tensor5]

Description

I'm using Buildah to build an OCI image with Gitlab CI and quay.io/buildah/stable. Setting the environment variable STORAGE_DRIVER=vfs produces:

vfs driver does not support overlay.imagestore options

while buildah --storage-driver=vfs bud . works as expected.

Steps to reproduce the issue:

1. podman run --privileged --rm -ti quay.io/buildah/stable
2. STORAGE_DRIVER=vfs buildah info
3. buildah --storage-driver=vfs info

Describe the results you received:

# STORAGE_DRIVER=vfs buildah info
vfs driver does not support overlay.imagestore options

# buildah --storage-driver=vfs info
{
    "host": {
        "Distribution": {
            "distribution": "fedora",
            "version": "30"
        },
        "MemTotal": 1030774784,
        "MenFree": 166924288,
        "SwapFree": 0,
        "SwapTotal": 0,
        "arch": "amd64",
        "cpus": 1,
        "hostname": "5166d2068028",
        "kernel": "5.1.12-300.fc30.x86_64",
        "os": "linux",
        "rootless": false,
        "uptime": "1969h 22m 16.66s (Approximately 82.04 days)"
    },
    "store": {
        "ContainerStore": {
            "number": 0
        },
        "GraphDriverName": "vfs",
        "GraphOptions": [],
        "GraphRoot": "/var/lib/containers/storage",
        "GraphStatus": {},
        "ImageStore": {
            "number": 3
        },
        "RunRoot": "/var/run/containers/storage"
    }
}

Describe the results you expected:
Same result from both commands.

Output of rpm -q buildah or apt list buildah:

buildah-1.10.1-2.git8c1c2c5.fc30.x86_64

Output of buildah version:

Version:         1.10.1
Go Version:      go1.12.7
Image Spec:      1.0.1
Runtime Spec:    1.0.1-dev
CNI Spec:        0.4.0
libcni Version:  
Git Commit:      
Built:           Thu Jan  1 00:00:00 1970
OS/Arch:         linux/amd64

Output of cat /etc/*release:

Fedora release 30 (Thirty)
NAME=Fedora
VERSION="30 (Container Image)"
ID=fedora
VERSION_ID=30
VERSION_CODENAME=""
PLATFORM_ID="platform:f30"
PRETTY_NAME="Fedora 30 (Container Image)"
ANSI_COLOR="0;34"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:30"
HOME_URL="https://fedoraproject.org/"
DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora/f30/system-administrators-guide/"
SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=30
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=30
PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
VARIANT="Container Image"
VARIANT_ID=container
Fedora release 30 (Thirty)
Fedora release 30 (Thirty)

Output of uname -a:

Linux gitlab-runner-bastion 5.1.12-300.fc30.x86_64 #1 SMP Wed Jun 19 15:19:49 UTC 2019 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 = [
"/var/lib/shared",
]

# 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,metacopy=on"

# 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"

[rhatdan]

Disabling the mount options in /etc/containers/storage.conf should allow you to use the Environment variable. The options are for the Overlay Driver.

[rhatdan]

In buildah code we do:

	if c.Flag("storage-driver").Changed {
		options.GraphDriverName = globalFlagResults.StorageDriver
		// If any options setup in config, these should be dropped if user overrode the driver
		options.GraphDriverOptions = []string{}
	}

But the storage library handles the environment variable, which is why they are different.

We have talked about changin the storage library to make the options driver specific, which is really the long term solution to this problem.

[tensor5]

Thanks for your reply, I'm looking forward to be able to use quay.io/buildah/stable out-of-the-box for CI with no extra configuration.

[rhatdan]

I don't believe we have this issue any longer, reopen if I am mistaken.

[Fodoj]

This is what I have on current buildah/stable (for root user it picks driver correctly):

su buildah
STORAGE_DRIVER=vfs buildah info
{
    "host": {
        "CgroupVersion": "v1",
        "Distribution": {
            "distribution": "fedora",
            "version": "32"
        },
        "MemTotal": 3721777152,
        "MenFree": 1137807360,
        "OCIRuntime": "runc",
        "SwapFree": 0,
        "SwapTotal": 0,
        "arch": "amd64",
        "cpus": 2,
        "hostname": "runner-6aaskeaz-project-20381742-concurrent-0676zf",
        "kernel": "3.10.0-1127.el7.x86_64",
        "os": "linux",
        "rootless": true,
        "uptime": "91h 27m 22.43s (Approximately 3.79 days)"
    },
    "store": {
        "ContainerStore": {
            "number": 0
        },
        "GraphDriverName": "overlay",
        "GraphOptions": [
            "overlay.mount_program=/usr/bin/fuse-overlayfs"
        ],
        "GraphRoot": "/home/build/.local/share/containers/storage",
        "GraphStatus": {
            "Backing Filesystem": "overlayfs",
            "Native Overlay Diff": "false",
            "Supports d_type": "true",
            "Using metacopy": "false"
        },
        "ImageStore": {
            "number": 1
        },
        "RunRoot": "/var/tmp/1000/containers"
    }
}

[marcelrend]

A rootless buildah container will use the local storage.conf file in $HOME/.config/containers/storage.conf.