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doc: PXE usage: move environment variables to a separate section
This works better with RST formatting, and avoids duplication. Signed-off-by: Fiona Klute <fiona.klute@gmx.de> Cc: Tom Rini <trini@konsulko.com>
This commit is contained in:
Fiona Klute
committed by
Heinrich Schuchardt
Heinrich Schuchardt
parent
80bf3ad511
commit
773830f4d9
@@ -17,33 +17,8 @@ Commands
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follows PXELINUX's rules for retrieving configuration files
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from a tftp server, and supports a subset of PXELINUX's config
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file syntax.
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**Environment**
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``pxe get`` requires two environment variables to be set:
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``pxefile_addr_r`` - should be set to a location in RAM large
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enough to hold pxe files while they're being processed. Up to
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16 config files may be held in memory at once. The exact
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number and size of the files varies with how the system is
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being used. A typical config file is a few hundred bytes long.
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``bootfile``, ``serverip`` - these two are typically set in
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the DHCP response handler, and correspond to fields in the
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DHCP response.
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``pxe get`` optionally supports these two environment
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variables being set:
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``ethaddr`` - this is the standard MAC address for the
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ethernet adapter in use. ``pxe get`` uses it to look for a
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configuration file specific to a system's MAC address.
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``pxeuuid`` - this is a UUID in standard form using lower case
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hexadecimal digits, for example,
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550e8400-e29b-41d4-a716-446655440000. ``pxe get`` uses it to
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look for a configuration file based on the system's UUID.
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file syntax. It requires certain environment variables to be
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set, see the Environment section below.
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**File Paths**
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@@ -62,54 +37,75 @@ Commands
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``pxefile_addr_r`` is an optional argument giving the location
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of the pxe file. The file must be terminated with a NUL byte.
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**Environment**
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There are some environment variables that may need to be set,
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depending on conditions.
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depending on conditions, see the Environment section below.
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``pxefile_addr_r`` - if the optional argument
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``pxefile_addr_r`` is not supplied, an environment variable
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named ``pxefile_addr_r`` must be supplied. This is typically
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the same value as is used for the ``pxe get`` command.
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Environment
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-----------
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``bootfile`` - typically set in the DHCP response handler
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based on the same field in the DHCP respone, this path is used
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to generate the base directory that all other paths to files
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retrieved by ``pxe boot`` will use. If no bootfile is
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specified, paths used in pxe files will be used as is.
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``pxefile_addr_r``
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Should be set to a location in RAM large enough to hold pxe
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files while they're being processed. Up to 16 config files may
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be held in memory at once. The exact number and size of the
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files varies with how the system is being used. A typical
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config file is a few hundred bytes long. Required for ``pxe
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get``, for ``pxe boot`` if the optional argument
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``pxefile_addr_r`` is not supplied.
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``serverip`` - typically set in the DHCP response handler,
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this is the IP address of the tftp server from which other
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files will be retrieved.
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``bootfile``
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Typically set in the DHCP response handler, required for ``pxe
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get``. For ``pxe boot``, this path is used to generate the
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base directory that all other paths to files retrieved by
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``pxe boot`` will use. If no bootfile is specified, paths used
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in pxe files will be used as is.
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``kernel_addr_r``, ``initrd_addr_r`` - locations in RAM at
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which ``pxe boot`` will store the kernel(or FIT image) and
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initrd it retrieves from tftp. These locations will be passed
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to the bootm command to boot the kernel. These environment
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variables are required to be set.
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``serverip``
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Typically set in the DHCP response handler, this is the IP
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address of the tftp server from which other files will be
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retrieved. Required for ``pxe get``.
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``fdt_addr_r`` - location in RAM at which ``pxe boot`` will
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store the fdt blob it retrieves from tftp. The retrieval is
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possible if ``fdt`` label is defined in pxe file and
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``fdt_addr_r`` is set. If retrieval is possible,
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``fdt_addr_r`` will be passed to bootm command to boot the
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kernel.
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``kernel_addr_r``, ``initrd_addr_r``
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Locations in RAM to store the kernel (or FIT image) and
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initrd. These locations will be passed to the ``bootm``
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command to boot the kernel. These environment variables are
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required to be set.
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``fdt_addr`` - the location of a fdt blob. ``fdt_addr`` will
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be passed to ``bootm`` command if it is set and ``fdt_addr_r``
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is not passed to bootm command.
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``fdt_addr_r``
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Location in RAM to store the retrieved fdt blob. Retrieval is
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possible if ``fdt`` label is defined in pxe file and
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``fdt_addr_r`` is set. If retrieval is possible,
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``fdt_addr_r`` will be passed to ``bootm`` command to boot the
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kernel.
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``fdtoverlay_addr_r`` - location in RAM at which 'pxe boot'
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will temporarily store fdt overlay(s) before applying them to
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the fdt blob stored at ``fdt_addr_r``.
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``fdt_addr``
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Location of a fdt blob. ``fdt_addr`` will be passed to
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``bootm`` command if it is set and ``fdt_addr_r`` is not
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passed to bootm command.
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``pxe_label_override`` - override label to be used, if exists,
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instead of the default label. This will allow consumers to
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choose a pxe label at runtime instead of having to prompt the
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user. If ``pxe_label_override`` is set but does not exist in
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the pxe menu, pxe would fallback to the default label if
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given, and no failure is returned but rather a warning
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message.
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``fdtoverlay_addr_r``
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Location in RAM to temporarily store fdt overlay(s) before
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applying them to the fdt blob stored at
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``fdt_addr_r``. Required to use the ``fdtoverlays`` command in
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the PXE file.
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``pxe_label_override``
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Override label to be used, if exists, instead of the default
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label. This will allow consumers to choose a pxe label at
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runtime instead of having to prompt the user. If
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``pxe_label_override`` is set but does not exist in the pxe
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menu, pxe would fallback to the default label if given, and no
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failure is returned but rather a warning message.
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``ethaddr``
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This is the standard MAC address for the ethernet adapter in
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use. ``pxe get`` uses it to look for a configuration file
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specific to a system's MAC address.
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``pxeuuid``
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This is a UUID in standard form using lower case hexadecimal
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digits, for example,
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550e8400-e29b-41d4-a716-446655440000. ``pxe get`` uses it to
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look for a configuration file based on the system's UUID.
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pxe file format
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---------------
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