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RUMP_SERVER(1) General Commands Manual RUMP_SERVER(1)


rump_server, rump_allserverrump kernel server


rump_server [-s] [-c ncpu] [-d drivespec] [-l library] [-m module] 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 command line as described in the options section.

-c ncpu
Configure ncpu virtual CPUs on SMP-capable archs. By default, the number of CPUs equals the number of CPUs on the host.
-d drivespec
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:
Block device path in rump kernel namespace. This must be specified according to the rules for a key in rump_etfs(3).
Host file used for storage. If the file does not exist, it will be created.
Size of the mapping. Similar to dd(1), this argument 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 regular file.
Use a disklabel partition identifier to specify the offset and size of the mapping. hostpath must contain an existing and valid disklabel within the first 64k.

The following are optional:

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 used.
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 accommodate the specified size, it will be extended to the specified size.

-l library
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).

-m module
Load and link a kernel module after the rump kernel is initialized. For this to work, the rump kernel must include the vfs faction, since the module is loaded using kernel vfs code (see EXAMPLES).
-r total_ram
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 virtual 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.
Do not detach from the terminal. By default, rump_server detaches from the terminal once the service is running on url.
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 immediately afterwards:

$ 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
January 15, 2014 NetBSD 7.0