Booting with an NFS Root Filesystem - Revision history

CBost at 20:42, 20 December 2019

2019-12-20T20:42:16Z

CBost at 20:41, 20 December 2019

2019-12-20T20:41:40Z

Mgloff at 23:24, 4 March 2019

2019-03-04T23:24:38Z

Bserrano at 19:05, 11 April 2014

2014-04-11T19:05:24Z

Bserrano at 21:23, 6 March 2014

2014-03-06T21:23:06Z

Bserrano at 21:16, 6 March 2014

2014-03-06T21:16:23Z

Mwelling at 19:11, 3 January 2014

2014-01-03T19:11:36Z

Mwelling: /* Configuring U-Boot */

2014-01-03T19:09:56Z

‎Configuring U-Boot

Mdean: Tagged MW to review.

2014-01-03T18:48:40Z

Tagged MW to review.

Mdean: Undo revision 2689 by Mgloff (talk)

2014-01-03T18:47:36Z

Undo revision 2689 by Mgloff (talk)

← Older revision		Revision as of 20:42, 20 December 2019
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	Set the bootargs variable to tell the kernel to boot into the NFS filesystem:		Set the bootargs variable to tell the kernel to boot into the NFS filesystem:
−
−	~~On '''initial use''' of U-boot the console variable should be set to the device's debug UART and buad rate, so kernel boot information can be displayed to the console. This is done as follows.~~
−	~~U-Boot> setenv console ttyXX 1152000~~
−	~~U-Boot> saveenv~~
−	~~Where ''XX'' should be replaced by your devices default debug UART.~~

	{{note \| On '''initial use''' of U-boot the console variable should be set to the device's debug UART and buad rate, so kernel boot information can be displayed to the console. This is done as follows.		{{note \| On '''initial use''' of U-boot the console variable should be set to the device's debug UART and buad rate, so kernel boot information can be displayed to the console. This is done as follows.

@@ Line 32: / Line 32: @@
 Set the bootargs variable to tell the kernel to boot into the NFS filesystem:
   U-Boot> setenv bootargs console=${console} root=/dev/nfs rootfstype=nfs ip=dhcp nfsroot=10.0.0.20:/srv/nfs/test_fileystem
   U-Boot> run bootargs
 This line sets up the environment needed to boot from the NFS server.  These options will be passed to the Linux kernel when booting it.  The <code>console=${console}</code> part tells Linux to use the console setting from the U-Boot environment variable; this will usually be something along the lines of <code>console=ttyS0,115200n8</code>.  The <code>root=/dev/nfs</code> directive tells Linux to instantiate with the virtual device, <code>/dev/nfs</code>, as the root filesystem.  The <code>rootfstype=nfs</code> directive tells Linux that the root filesystem is of the NFS variety.  The <code>ip=dhcp</code> directive tells Linux to acquire an IP address by requesting one from the DHCP server.  The <code>nfsroot=10.0.0.20:/srv/nfs/test_filesystem</code> directive tells Linux to look for an NFS server at <code>10.0.0.20</code> and to mount the <code>/srv/nfs/test_filesystem</code> directory as the root filesystem for the machine.

@@ Line 1: / Line 1: @@
 {{#seo:
 |title=Booting with an NFS Root Filesystem
@@ Line 17: / Line 15: @@
 ===TFTP Server===
-A TFTP server is required to host the kernel image.  For information on installing a TFTP server, see [[Installing TFTP server]].
+A TFTP server is required if a kernel image is not already programmed in flash.  For information on installing a TFTP server, see [[Installing TFTP server]].
 ===NFS Server===
@@ Line 31: / Line 29: @@
 ==Configuring the Client to Boot from NFS==
-The method used to configure a client to boot with an NFS mounted root filesystem depends on the type of bootloader the machine uses.  Configuring U-Boot <!-- and LILO --> for booting over NFS is covered here.
+===Configuring U-Boot===
-<!--
-Most ARM-based systems use U-Boot as the bootloader.  For ARM machines, start with the U-Boot section.  Most x86 machines, on the other hand, use LILO as the bootloader; for such a machine, start with the LILO section.
+Set the bootargs variable to tell the kernel to boot into the NFS filesystem:
--->
-===Configuring U-Boot===
+If the kernel is already programmed into the flash, it can be used in most cases to boot into the NFS root filesystem. Execute the next line to load and run the default kernel.
-A series of U-Boot commands are used to tell U-Boot to boot an NFS filesystem:
+An alternate kernel can be loaded into memory temporarily and booted if the kernel is not already programmed in the flash or a development kernel is to be tested. Also see [[ Loading_Images_with_U-Boot#Executing_kernel_from_RAM  | Executing kernel from RAM ]]
   U-Boot> set autoload no
@@ Line 50: / Line 58: @@
 This line sets the IP address of the TFTP server to <code>10.0.0.20</code>.  This is the server which hosts the Linux kernel which will be used by the machine.
- U-Boot> setenv bootargs console=${console} root=/dev/nfs rootfstype=nfs ip=dhcp nfsroot=10.0.0.20:/srv/nfs/test_fileystem
+  U-Boot> tftp ${loadaddr} zImage
   ...
   Loading: #################################################################
@@ Line 67: / Line 71: @@
            #####################
-This line tells U-Boot to load the kernel from the TFTP server, whose IP address was set earlier with the <code>set serverip 10.0.0.20</code> command.  The filename U-Boot requests from the TFTP server is <code>uImage</code>, and it stores it in the memory location pointed to by <code>loadaddr</code>.  The text which follows displays U-Boot's progress in loading the kernel into RAM.  When the U-Boot prompt returns, the environment is fully setup and ready to boot from an NFS root filesystem.
+This line tells U-Boot to load the kernel from the TFTP server, whose IP address was set earlier with the <code>set serverip 10.0.0.20</code> command.  The filename U-Boot requests from the TFTP server is <code>zImage</code>, and it stores it in the memory location pointed to by <code>loadaddr</code>.  The text which follows displays U-Boot's progress in loading the kernel into RAM.  When the U-Boot prompt returns, the environment is fully setup and ready to boot from an NFS root filesystem.
-  U-Boot> bootm ${loadaddr}
+  U-Boot> bootz ${loadaddr}
-The <code>bootm</code> command tells U-Boot to boot from RAM.  This means it boots the kernel which was just loaded into RAM, passing the commandline arguments specified by <code>bootargs</code> to the Linux kernel as it does so.
+The <code>bootz</code> command tells U-Boot to boot the kernel from RAM.  This means it boots the kernel which was just loaded into RAM, passing the commandline arguments specified by <code>bootargs</code> to the Linux kernel as it does so.
 The machine should now boot, and show output on its console as it does so.
 ==Conclusion==
-Using NFS for the root filesystem allows boards to boot quickly into test versions of a filesystem, provides a tool for remotely backing up the filesystem installed on an embedded machine, can provide a central filesystem image for many boards which can allow updating one filesystem to update all boards which use it simultaneously, and more.  Setting up a machine to boot to a root filesystem via NFS requires little work; most of the work is in setting up the server.  The ability to boot a root filesystem over NFS provides a powerful tool for many applications.
+Using NFS for the root filesystem allows boards to boot quickly into test versions of a filesystem, provides a tool for remotely backing up the filesystem installed on an embedded machine, can provide a central filesystem image for many boards which can allow updating one filesystem to update all boards which use it simultaneously, and more.  Setting up a machine to boot to a root filesystem via NFS requires little work; most of the work is in setting up the server.

← Older revision		Revision as of 19:05, 11 April 2014
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−	{{todo\|~~SEOKWTODO~~; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+);(01.03.14-13:10->MW+);(03.06.14-15:15->BS-)\|Mike Dean\|project=oe 4,oe 5,md,~~SEOKWTODO~~,ky,mw,bs}}	+	{{todo\|SEOKWREV; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+);(01.03.14-13:10->MW+);(03.06.14-15:15->BS-);(04.11.14-14:05->BS+)\|Mike Dean\|project=oe 4,oe 5,md,SEOKWREV,ky,mw,bs}}

		+	{{#seo:
		+	\|title=Booting with an NFS Root Filesystem
		+	\|titlemode=append
		+	\|keywords=TFTP Server,NFS Server,U-Boot,Root File System
		+	\|description=This page describes the steps required to boot over NFS.
		+	}}
	It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.		It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.

← Older revision		Revision as of 21:23, 6 March 2014
Line 1:		Line 1:
−	{{todo\|SEOKWTODO; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+);(01.03.14-13:10->MW+);(03.06.14-15:15->BS+)\|Mike Dean\|project=oe 4,oe 5,md,SEOKWTODO,ky,mw,bs}}	+	{{todo\|SEOKWTODO; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+);(01.03.14-13:10->MW+);(03.06.14-15:15->BS-)\|Mike Dean\|project=oe 4,oe 5,md,SEOKWTODO,ky,mw,bs}}

	It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.		It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.

← Older revision		Revision as of 21:16, 6 March 2014
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−	{{todo\|~~Complete~~; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+);(01.03.14-13:10->MW+)\|Mike Dean\|project=oe 4,oe 5,md,~~Complete~~,ky,mw}}	+	{{todo\|SEOKWTODO; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+);(01.03.14-13:10->MW+);(03.06.14-15:15->BS+)\|Mike Dean\|project=oe 4,oe 5,md,SEOKWTODO,ky,mw,bs}}

	It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.		It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.

← Older revision		Revision as of 19:11, 3 January 2014
Line 1:		Line 1:
−	{{todo\|~~FinalDraft~~; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+)\|Mike Dean\|project=oe 4,oe 5,md,~~FinalDraft~~,ky,mw}}	+	{{todo\|Complete; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+);(01.03.14-13:10->MW+)\|Mike Dean\|project=oe 4,oe 5,md,Complete,ky,mw}}

	It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.		It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.

← Older revision		Revision as of 18:48, 3 January 2014
Line 1:		Line 1:
−	{{todo\|~~Final~~; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+)\|Mike Dean\|project=oe 4,oe 5,md,FinalDraft,ky}}	+	{{todo\|FinalDraft; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+)\|Mike Dean\|project=oe 4,oe 5,md,FinalDraft,ky,mw}}

	It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.		It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.

@@ Line 1: / Line 1: @@
-{{todo|Complete; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+);(12.30.13-18:30->MG+)|Mike Dean|project=oe 4,oe 5,md,ky,mg,Complete}}
+{{todo|Final; (12.18.13-22:30->MD+);(12.19.13-13:20->MD+);(12.19.13-17:00->KY+)|Mike Dean|project=oe 4,oe 5,md,FinalDraft,ky}}
 It is possible to boot most EMAC OE systems using NFS (Network File System) as the root filesystem. This method can be especially useful during development where the root filesystem is changing frequently. This can save time as well as wear on the on-board flash device. This page describes the steps required to boot over NFS.
@@ Line 38: / Line 38: @@
   DHCP client bound to address 10.0.0.100
-* <code>set autoload no</code> - tell U-Boot not to try to load an image after an IP address is acquired from the DHCP server.
+Here, the first command, <code>set autoload no</code>, tells U-Boot not to try to load an image after they've gotten an IP address from the DHCP server.  The second command, <code>dhcp</code>, tells U-Boot to use DHCP to acquire an IP address.  In this example, the DHCP server assigned <code>10.0.0.100</code> as the IP address for the machine.
   U-Boot> set serverip 10.0.0.20
-* set the IP address of the TFTP server to <code>10.0.0.20</code>.  This is the server which hosts the Linux kernel which will be used by the machine.
+This line sets the IP address of the TFTP server to <code>10.0.0.20</code>.  This is the server which hosts the Linux kernel which will be used by the machine.
   U-Boot> setenv bootargs console=${console} root=/dev/nfs rootfstype=nfs ip=dhcp nfsroot=10.0.0.20:/srv/nfs/test_fileystem
-This line sets up the environment needed to boot from the NFS server.  These options will be passed to the Linux kernel when booting it.
+This line sets up the environment needed to boot from the NFS server.  These options will be passed to the Linux kernel when booting it.  The <code>console=${console}</code> part tells Linux to use the console setting from the U-Boot environment variable; this will usually be something along the lines of <code>console=ttyS0,115200n8</code>.  The <code>root=/dev/nfs</code> directive tells Linux to instantiate with the virtual device, <code>/dev/nfs</code>, as the root filesystem.  The <code>rootfstype=nfs</code> directive tells Linux that the root filesystem is of the NFS variety.  The <code>ip=dhcp</code> directive tells Linux to acquire an IP address by requesting one from the DHCP server.  The <code>nfsroot=10.0.0.20:/srv/nfs/test_filesystem</code> directive tells Linux to look for an NFS server at <code>10.0.0.20</code> and to mount the <code>/srv/nfs/test_filesystem</code> directory as the root filesystem for the machine.
   U-Boot> tftp ${loadaddr} uImage
@@ Line 67: / Line 61: @@
            #####################
-* <code>tftp ${loadaddr} uImage</code> - tells U-Boot to load the kernel from the TFTP server, whose IP address was set earlier with the <code>set serverip 10.0.0.20</code> command. The filename U-Boot requests from the TFTP server is <code>uImage</code>, and it stores it in the memory location pointed to by <code>loadaddr</code>. The text which follows displays U-Boot's progress in loading the kernel into RAM. When the U-Boot prompt returns, the environment is fully setup and ready to boot from an NFS root filesystem.
+This line tells U-Boot to load the kernel from the TFTP server, whose IP address was set earlier with the <code>set serverip 10.0.0.20</code> command.  The filename U-Boot requests from the TFTP server is <code>uImage</code>, and it stores it in the memory location pointed to by <code>loadaddr</code>.  The text which follows displays U-Boot's progress in loading the kernel into RAM.  When the U-Boot prompt returns, the environment is fully setup and ready to boot from an NFS root filesystem.
   U-Boot> bootm
-* <code>bootm</code> tells U-Boot to boot from RAM. This means it boots the kernel which was just loaded into RAM, passing the commandline arguments specified by <code>bootargs</code> to the Linux kernel as it does so.
+The <code>bootm</code> command tells U-Boot to boot from RAM.  This means it boots the kernel which was just loaded into RAM, passing the commandline arguments specified by <code>bootargs</code> to the Linux kernel as it does so.
 The machine should now boot, and show output on its console as it does so.
-If it is desired to have the machine boot from NFS every time type in the command below before booting.
+<!--NOTE: It may be a good idea to tell the reader how to save this configuration to the environment so that it will automatically boot this way every time.  We can do this on demand, though. -->
 <!--
 ===Configuring LILO===
@@ Line 89: / Line 80: @@
 ==Conclusion==
-Using NFS for the root filesystem allows boards to boot quickly into test versions of a filesystem, provides a tool for remotely backing up the filesystem installed on an embedded machine, can provide a central filesystem image for many boards which can allow updating one filesystem to update all boards which use it simultaneously, and more. Setting up a machine to boot to a root filesystem via NFS requires little work; most of the work is in setting up the server.
+Using NFS for the root filesystem allows boards to boot quickly into test versions of a filesystem, provides a tool for remotely backing up the filesystem installed on an embedded machine, can provide a central filesystem image for many boards which can allow updating one filesystem to update all boards which use it simultaneously, and more.  Setting up a machine to boot to a root filesystem via NFS requires little work; most of the work is in setting up the server.  The ability to boot a root filesystem over NFS provides a powerful tool for many applications.