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RUMP_SERVER(1) NetBSD General Commands Manual RUMP_SERVER(1)
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rump_server, rump_allserver -- rump kernel server
rump_server [-sv] [-c ncpu] [-d drivespec] [-l library] [-m module]
[-r total_ram] url
The rump_server utility is used to provide a rump kernel service.
Clients can use the system calls provided by rump_server via url.
The difference between rump_server and rump_allserver is that rump_server
offers only a minimalistic set of features, while rump_allserver provides
all rump kernel components which were available when the system was
built. At execution time it is possible to load components from the com-
mand line as described in the options section.
Configure ncpu virtual CPUs on SMP-capable archs. By default,
the number of CPUs equals the number of CPUs on the host.
The argument drivespec maps a host file in the rump kernel fs
namespace. The string drivespec must be of comma-separated
``name=value'' format and must contain the following tokens:
key Block device path in rump kernel namespace. This
must be specified according to the rules for a key
hostpath Host file used for storage. If the file does not
exist, it will be created.
size Size of the mapping. Similar to dd(1), this argu-
ment accepts a suffix as the multiplier for the
number. The special value ``host'' indicates that
the current size of hostpath will be used. In this
case it is assumed that hostpath exists and is a
disklabel Use a disklabel partition identifier to specify the
offset and size of the mapping. hostpath must con-
tain an existing and valid disklabel within the
The following are optional:
offset Offset of the mapping. The window into hostpath
therefore is [offset, offset+size]. In case this
parameter is not given, the default value 0 is
type The type of file that key is exposed as within the
rump kernel. The possibilities are ``blk'',
``chr'', and ``reg'' for block device, character
device and regular file, respectively. The default
is a block device.
Note: the contents of block devices are cached in
the rump kernel's buffer cache. To avoid cache
incoherency, it is advisable not to access a file
through the host namespace while it is mapped as a
block device in a rump kernel.
In case hostpath does not exist, it will be created as a regular
file with mode 0644 (plus any restrictions placed by umask). In
case hostpath is a regular file and is not large enough to accom-
modate the specified size, it will be extended to the specified
Call dlopen() on library before initializing the rump kernel. In
case library provides a kernel module, it will appear as a
builtin module in the rump kernel. Any rump kernel component
present in library will also be initialized.
The argument library can contain a full path or a filename, in
which case the standard dynamic library search path will be used.
By default, lazy resolution is used, and may result in a runtime
error due to missing components. To test a configuration, run
rump_server with LD_BIND_NOW=1 (see examples).
Load and link a kernel module after the rump kernel is initial-
ized. For this to work, the rump kernel must include the vfs
faction, since the module is loaded using kernel vfs code (see
Sets the limit of kernel memory allocatable by the server to
total_ram as opposed to the default which allows the server to
allocate as much memory as the host will give it. This parameter
is especially useful for VFS servers, since by default the vir-
tual file system will attempt to consume as much memory as it
can, and accessing large files can cause an excessive amount of
memory to be used as file system cache.
-s Do not detach from the terminal. By default, rump_server
detaches from the terminal once the service is running on url.
-v Set bootverbose.
After use, rump_server can be made to exit using rump.halt(1).
Start a server and load the tmpfs file system module, and halt the server
$ rump_server -lrumpvfs -m /modules/tmpfs.kmod unix://sock
$ env RUMP_SERVER=unix://sock rump.halt
Start a server with the one gigabyte host file dk.img mapped as the block
device /dev/dk in the rump kernel.
$ rump_allserver -d key=/dev/dk,hostpath=dk.img,size=1g unix://sock
Start a server which listens on INADDR_ANY port 3755
$ rump_server tcp://0:3755/
Test that a configuration contains all of the necessary components:
$ env LD_BIND_NOW=1 rump_server -lrumpvfs -lrumpfs_ffs unix://tsock
Start a FFS server with a 16MB kernel memory limit.
$ rump_server -lrumpfs_ffs [...] -r 16m unix://ffs
rump.halt(1), dlopen(3), rump(3), rump_sp(7)
NetBSD 9.3 January 15, 2014 NetBSD 9.3