diff options
Diffstat (limited to 'etc/rc.initdiskless')
| -rw-r--r-- | etc/rc.initdiskless | 136 |
1 files changed, 87 insertions, 49 deletions
diff --git a/etc/rc.initdiskless b/etc/rc.initdiskless index 56a19c1..b84dab9 100644 --- a/etc/rc.initdiskless +++ b/etc/rc.initdiskless @@ -31,58 +31,96 @@ # On entry to this script the entire system consists of a read-only root -# mounted via NFS. We use the contents of /conf to create and populate -# memory filesystems. The kernel has run BOOTP and configured an interface +# mounted via NFS. The kernel has run BOOTP and configured an interface # (otherwise it would not have been able to mount the NFS root!) # -# The following directories are scanned. Each sucessive directory overrides -# (is merged into) the previous one. -# -# /conf/base universal base -# /conf/default modified by a secondary universal base -# /conf/${ipba} modified based on the assigned broadcast IP -# /conf/${ip} modified based on the machine's assigned IP -# -# Each of these directories may contain any number of subdirectories which -# represent directories in / on the diskless machine. The existance of -# these subdirectories causes this script to create a MEMORY FILESYSTEM for -# /<sub_directory_name>. For example, if /conf/base/etc exists then a -# memory filesystem will be created for /etc. -# -# If a subdirectory contains the file 'remount' the contents of the file -# is a mount command used to remount the subdirectory prior to it being -# copied. An example contents could be: "mount -o ro /dev/ad0s3". Note -# that the directory to be mounted on is supplied by this script. -# -# If a subdirectory contains the file 'diskless_remount' the contents of -# the file is used to remount the subdirectory prior to it being copied to -# the memory filesystem. For example, if /conf/base/etc/diskless_remount -# contains the string 'my.server.com:/etc' then my.server.com:/etc will be -# mounted in place of the subdirectory. This allows you to avoid making -# duplicates of system directories in /conf. Special processing is done -# to allow specifications relative to the root filesystem. -# -# If a subdirectory contains the file 'md_size', the contents of the -# file is used to determine the size of the memory filesystem, in 512 -# byte sectors. The default is 10240 (5MB). You only have to specify an -# md_size if the default doesn't work for you (i.e. if it is too big or -# too small). For example, /conf/base/etc/md_size might contain '16384'. -# -# If /conf/<special_dir>/SUBDIR.cpio.gz exists, the file is cpio'd into -# the specified /SUBDIR (and a memory filesystem is created for /SUBDIR -# if necessary). -# -# If /conf/<special_dir>/SUBDIR.remove exists, the file contains a list -# of paths which are rm -rf'd relative to /SUBDIR. -# -# You will almost universally want to create a /conf/base/etc containing -# a diskless_remount and possibly an md_size file. You will then almost -# universally want to override rc.conf, rc.local, and fstab by creating -# /conf/default/etc/{rc.conf,rc.local,fstab}. Your fstab should be sure -# to mount a /usr... typically an NFS readonly /usr. -# -# NOTE! /var, /tmp, and /dev will be created elsewhere. +# We use the contents of /conf to create and populate memory filesystems +# that are mounted on top of this root to implement the writable +# (and host-specific) parts of the root filesystem, and other volatile +# filesystems. +# +# The hierarchy in /conf has the form /conf/T/M/ where M are directories +# for which memory filesystems will be created and filled, +# and T is one of the "template" directories below: +# +# base universal base, typically a replica of the original root; +# default secondary universal base, typically overriding some +# of the files in the original root; +# ${ipba} where ${ipba} is the assigned broadcast IP address +# ${class} where ${class} is a list of directories supplied by +# bootp/dhcp through the T134 option. +# ${ipba} and ${class} are typicall used to configure features +# for group of diskless clients, or even individual features; +# ${ip} where ${ip} is the machine's assigned IP address, typically +# used to set host-specific features; +# +# Template directories are scanned in the order they are listed above, +# with each sucessive directory overriding (merged into) the previous one; +# non-existing directories are ignored. +# +# The existence of a directory /conf/T/M causes this script to create a +# memory filesystem mounted as /M on the client. +# +# Some files in /conf have special meaning, namely: +# +# Filename Action +# ---------------------------------------------------------------- +# /conf/T/M/remount +# The contents of the file is a mount command. E.g. if +# /conf/1.2.3.4/foo/remount contains "mount -o ro /dev/ad0s3", +# then /dev/ad0s3 will be be mounted on /conf/1.2.3.4/foo/ +# +# /conf/T/M/diskless_remount +# The contents of the file points to an NFS filesystem. E.g. if +# /conf/base/etc/diskless_remount contains "foo.com:/etc", +# then foo.com:/etc will be be mounted on /conf/base/etc/ +# If the file contains a pathname starting with "/", then +# the root path is prepended to it; this allows relocation of +# the root filesystem withouth changing configuration files. +# +# /conf/T/M/md_size +# The contents of the file specifies the size of the memory +# filesystem to be created, in 512 byte blocks. +# The default size is 10240 blocks (5MB). E.g. if +# /conf/base/etc/md_size contains "30000" then a 15MB MFS +# will be created. In case of multiple entries for the same +# directory M, the last one in the scanning order is used. +# NOTE: If you only need to create a memory filesystem but not +# initialize it from a template, it is preferrable to specify +# it in fstab e.g. as "md /tmp mfs -s=30m,rw 0 0" +# +# /conf/T/SUBDIR.cpio.gz +# The file is cpio'd into /SUBDIR (and a memory filesystem is +# created for /SUBDIR if necessary). The presence of this file +# prevents the copy from /conf/T/SUBDIR/ +# +# /conf/T/SUBDIR.remove +# The list of paths contained in the file are rm -rf'd +# relative to /SUBDIR. +# +# You will almost universally want to create the following files under /conf +# +# File Content +# ---------------------------- ------------------------------------------ +# /conf/base/etc/md_size size of /etc filesystem +# /conf/base/diskless_remount "/etc" +# /conf/default/etc/rc.conf generic diskless config parameters +# /conf/default/etc/fstab generic diskless fstab e.g. like this +# +# foo:/root_part / nfs ro 0 0 +# foo:/usr_part /usr nfs ro 0 0 +# foo:/home_part /home nfs rw 0 0 +# md /tmp mfs -s=30m,rw 0 0 +# md /var mfs -s=30m,rw 0 0 +# proc /proc procfs rw 0 0 +# +# plus, possibly, overrides for password files etc. +# +# NOTE! /var, /tmp, and /dev will be typically created elsewhere, e.g. +# as entries in the fstab as above. # Those filesystems should not be specified in /conf. +# +# (end of documentation, now get to the real code) dlv=`/sbin/sysctl -n vfs.nfs.diskless_valid 2> /dev/null` [ ${dlv:=0} -eq 0 ] && [ ! -f /etc/diskless ] && exit 0 |
