mount nfs share from <server-ip>:/<root-dir>, if no server-ip is given, use
dhcp next_server. If server-ip is an IPv6 address it has to be put in
brackets, e.g. [2001:DB8::1]. NFS options can be appended with the prefix
- ":" or "," and are seperated by ",".
+ ":" or "," and are separated by ",".
**root=**nfs:\[_<server-ip>_:]__<root-dir>__[:__<nfs-options>__], **root=**nfs4:\[_<server-ip>_:]__<root-dir>__[:__<nfs-options>__], **root=**__{dhcp|dhcp6}__::
root=dhcp alone directs initrd to look at the DHCP root-path where NFS
FCoE
~~~~
+**rd.nofcoe=0**::
+ disable FCoE and lldpad
+
**fcoe=**__<edd|interface|MAC>__:__{dcb|nodcb}__:__{fabric|vn2vn}__::
Try to connect to a FCoE SAN through the NIC specified by _<interface>_ or
_<MAC>_ or EDD settings. The second argument specifies if DCB
Dracut offers multiple options for live booted images:
=====================
-SquashFS with read-only filesystem image::: The system will boot with a read
-only filesystem from the SquashFS and apply a writable device-mapper snapshot
-over the read only filesystem. Using this method ensures a relatively fast
-boot and lower RAM usage. Users **must be careful** to avoid writing too many
-blocks to the snapshot volume. Once the blocks of the snapshot overlay are
-exhausted, the root filesystem becomes read only and may cause application
-failures. The overlay file is marked 'Overflow', and a difficult recovery is
-required to repair and enlarge the overlay offline. Non-persistent overlays
-are sparse files in RAM that only consume content space as required blocks are
-allocated. They default to an apparent size of 32 GiB in RAM. The size can be
-adjusted with the **rd.live.overlay.size=** kernel command line option.
+SquashFS with read-only filesystem image::: The system will boot with a
+read-only filesystem from the SquashFS and apply a writable Device-mapper
+snapshot or an OverlayFS overlay mount for the read-only base filesystem. This
+method ensures a relatively fast boot and lower RAM usage. Users **must be
+careful** to avoid writing too many blocks to a snapshot volume. Once the
+blocks of the snapshot overlay are exhausted, the root filesystem becomes
+read-only and may cause application failures. The snapshot overlay file is
+marked 'Overflow', and a difficult recovery is required to repair and enlarge
+the overlay offline. Non-persistent overlays are sparse files in RAM that only
+consume content space as required blocks are allocated. They default to an
+apparent size of 32 GiB in RAM. The size can be adjusted with the
+**rd.live.overlay.size=** kernel command line option.
+
-The filesystem structure is expected to be:
+The filesystem structure is traditionally expected to be:
+
[listing]
--
-squashfs.img | Squashfs from LiveCD .iso downloaded via network
+squashfs.img | SquashFS from LiveCD .iso
!(mount)
/LiveOS
|- rootfs.img | Filesystem image to mount read-only
... |
--
+
-Dracut uses this method of live booting by default. No additional command line
-options are required other than **root=live:<URL>** to specify the location
-of your squashed filesystem.
+For OverlayFS mount overlays, the filesystem structure may also be a direct
+compression of the root filesystem:
++
+[listing]
+--
+squashfs.img | SquashFS from LiveCD .iso
+ !(mount)
+ /bin | Live filesystem
+ /boot |
+ /dev |
+ ... |
+--
++
+Dracut uses one of the overlay methods of live booting by default. No
+additional command line options are required other than **root=live:<URL>** to
+specify the location of your squashed filesystem.
+
- The compressed SquashFS image can be copied during boot to RAM at
`/run/initramfs/squashed.img` by using the **rd.live.ram=1** option.
-- A device with a persistent overlay can be booted read only by using the
+- A device with a persistent overlay can be booted read-only by using the
**rd.live.overlay.readonly** option on the kernel command line. This will
-cause a temporary, writable overlay to be stacked over a read-only snapshot
-of the root filesystem.
+either cause a temporary, writable overlay to be stacked over a read-only
+snapshot of the root filesystem or the OverlayFS mount will use an additional
+lower layer with the root filesystem.
+
Uncompressed live filesystem image:::
When the live system was installed with the '--skipcompress' option of the
__livecd-iso-to-disk__ installation script for Live USB devices, the root
-filesystem image, `rootfs.img`, is expanded on installation and no SquashFS
+filesystem image, __rootfs.img__, is expanded on installation and no SquashFS
is involved during boot.
+
- If **rd.live.ram=1** is used in this situation, the full, uncompressed
`/run` tmpfs.
+
- If **rd.live.overlay=none** is provided as a kernel command line option,
-a writable, linear device-mapper target is created on boot with no overlay.
+a writable, linear Device-mapper target is created on boot with no overlay.
-writable filesystem image:::
+Writable filesystem image:::
The system will retrieve a compressed filesystem image, extract it to
`/run/initramfs/fsimg/rootfs.img`, connect it to a loop device, create a
-writable, linear device-mapper target at `/dev/mapper/live-rw`, and mount that
+writable, linear Device-mapper target at `/dev/mapper/live-rw`, and mount that
as a writable volume at `/`. More RAM is required during boot but the live
filesystem is easier to manage if it becomes full. Users can make a filesystem
image of any size and that size will be maintained when the system boots. There
+
[listing]
--
-rootfs.tgz | Compressed tarball containing fileystem image
+rootfs.tgz | Compressed tarball containing filesystem image
!(unpack)
/rootfs.img | Filesystem image at /run/initramfs/fsimg/
!(mount)
This method is very suitable for diskless boots.
**root=**live:__<url>__::
-Boots a live image retrieved from __<url>__. Valid handlers: __http, https, ftp, torrent, tftp__.
+Boots a live image retrieved from __<url>__. Requires the dracut 'livenet'
+module. Valid handlers: __http, https, ftp, torrent, tftp__.
+
[listing]
-.Example
+.Examples
--
root=live:http://example.com/liveboot.img
root=live:ftp://ftp.example.com/liveboot.img
**rd.live.dir=**__<path>__::
Specifies the directory within the boot device where the squashfs.img or
-rootfs.img can be found. By default, this is __LiveOS__.
+rootfs.img can be found. By default, this is `/LiveOS`.
**rd.live.squashimg=**__<filename of SquashFS image>__::
Specifies the filename for a SquashFS image of the root filesystem.
**rd.live.ram=**1::
Copy the complete image to RAM and use this for booting. This is useful
-when the image resides on, i.e., a DVD which needs to be ejected later on.
+when the image resides on, e.g., a DVD which needs to be ejected later on.
-**rd.live.overlay=**__<devspec>__:__(<pathspec>|auto)__|__none__::
-Allow the usage of a permanent overlay.
-- _<devspec>_ specifies the path to a device with a mountable filesystem.
-- _<pathspec>_ is the path to a file within that filesystem, which shall be
+**rd.live.overlay={**__<devspec>__[:__{<pathspec>|auto}__]|__none__}::
+Manage the usage of a permanent overlay.
++
+--
+* _<devspec>_ specifies the path to a device with a mountable filesystem.
+* _<pathspec>_ is the path to a file within that filesystem, which shall be
used to persist the changes made to the device specified by the
**root=live:__<url>__** option.
-- _none_ specifies no overlay when an uncompressed live root filesystem is
-available.
-If a persistent overlay is detected at the standard LiveOS path, the overlay &
-overlay type detected (whether Device-mapper or OverlayFS) will be used.
++
+The default _pathspec_, when _auto_ or no _:<pathspec>_ is given, is
+`/<+++<b>rd.live.dir</b>+++>/overlay-<label>-<uuid>`, where _<label>_ is the
+device LABEL, and _<uuid>_ is the device UUID.
+* _none_ (the word itself) specifies that no overlay will be used, such as when
+an uncompressed, writable live root filesystem is available.
++
+If a persistent overlay __is detected__ at the standard LiveOS path, the
+overlay & overlay type detected, whether Device-mapper or OverlayFS, will be
+used.
+--
+
[listing]
-.Example
+.Examples
--
rd.live.overlay=/dev/sdb1:persistent-overlay.img
+rd.live.overlay=UUID=99440c1f-8daa-41bf-b965-b7240a8996f4
--
**rd.live.overlay.size=**__<size_MiB>__::
-Specifies a non-persistent overlay size in MiB. The default is _32768_.
+Specifies a non-persistent Device-mapper overlay size in MiB. The default is
+_32768_.
**rd.live.overlay.readonly=**1::
-Specifies a non-persistent, writable snapshot overlay to be stacked over a
-read-only snapshot of the root filesystem, `/dev/mapper/live-ro`, or a read-
-only loop device of a writable `rootfs.img`.
+This is used to boot with a normally read-write persistent overlay in a
+read-only mode. With this option, either an additional, non-persistent,
+writable snapshot overlay will be stacked over a read-only snapshot,
+`/dev/mapper/live‑ro`, of the base filesystem with the persistent overlay, or a
+read-only loop device, in the case of a writable __rootfs.img__, or an OverlayFS
+mount will use the persistent overlay directory linked at `/run/overlayfs‑r` as
+an additional lower layer along with the base root filesystem and apply a
+transient, writable upper directory overlay, in order to complete the booted
+root filesystem.
**rd.live.overlay.reset=**1::
-Specifies that a persistent overlay should be reset on boot. All root
+Specifies that a persistent overlay should be reset on boot. All previous root
filesystem changes are vacated by this action.
**rd.live.overlay.thin=**1::
anymore.
**rd.live.overlay.overlayfs=**1::
-Enables the use of the **OverlayFS** kernel module, if available, to provide a
+Enables the use of the *OverlayFS* kernel module, if available, to provide a
copy-on-write union directory for the root filesystem. OverlayFS overlays are
directories of the files that have changed on the read-only base (lower)
filesystem. The root filesystem is provided through a special overlay type
mount that merges the lower and upper directories. If an OverlayFS upper
directory is not present on the boot device, a tmpfs directory will be created
-at /run/overlayfs to provide temporary storage. Persistent storage can be
+at `/run/overlayfs` to provide temporary storage. Persistent storage can be
provided on vfat or msdos formatted devices by supplying the OverlayFS upper
directory within an embedded filesystem that supports the creation of trusted.*
extended attributes and provides a valid d_type in readdir responses, such as
with ext4 and xfs. On non-vfat-formatted devices, a persistent OverlayFS
overlay can extend the available root filesystem storage up to the capacity of
-the LiveOS device.
-
+the LiveOS disk device.
++
If a persistent overlay is detected at the standard LiveOS path, the overlay &
-overlay type detected (whether OverlayFS or Device-mapper) will be used.
-
+overlay type detected, whether OverlayFS or Device-mapper, will be used.
++
The **rd.live.overlay.readonly** option, which allows a persistent overlayfs to
-be mounted read only through a higher level transient overlay directory, has
+be mounted read-only through a higher level transient overlay directory, has
been implemented through the multiple lower layers feature of OverlayFS.
projects / thirdparty / dracut.git / blobdiff