mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-12-19 04:03:56 +00:00
90 lines
3.4 KiB
Plaintext
90 lines
3.4 KiB
Plaintext
Setting up and running Nix UML ("nixu")
|
|
|
|
It is possible to run Nix inside a User Mode Linux environment (UML). The Nix
|
|
expressions for this can be found at
|
|
https://svn.cs.uu.nl:12443/repos/trace/nixu/.
|
|
|
|
|
|
Installation on SuSE Linux 9
|
|
|
|
Download the latest nixpkgs collection and checkout the nixu trunk with
|
|
subversion. Install the uml and uml-utilities packages with Nix and run the
|
|
"make-disk.sh" script which can be found in nixu. After it has built
|
|
everything (or downloaded everything from the nixpkgs cache which can be
|
|
used with nix-pull) you can use the "run.sh" script to start the UML.
|
|
|
|
|
|
Installation on Fedora Core 1
|
|
|
|
Installing the Nix UML on Fedora Core 1 is a bit tricky. Nix relies on
|
|
Berkeley DB and there are issues with Berkeley DB and NPTL kernels (New POSIX
|
|
Thread Library) on Red Hat based systems. Since the system we build inside
|
|
UML does not use NPTL we cannot use the Nix we use on the host system to
|
|
fill the disk once we've booted our the kernel of our UML.
|
|
|
|
The solution is as follows:
|
|
|
|
- install all packages via the nix-pull mechanisms with the MANIFEST from
|
|
the official nix-pkgs site to avoid that impure builds link against the
|
|
NPTL glibc on the host system.
|
|
- install Nix in Nix
|
|
- in the nixu scripts edit make-disk.sh and fill-disk.sh.
|
|
In make-disk.sh prefix all nix-* commands with the absolute path to the
|
|
host-Nix installation bin directory (for example: /nix/bin). In
|
|
fill-disk.sh replace all /nix/bin paths with a relative path to the Nix
|
|
installed with Nix (for example: /usr/home/nix/.nix-profile/bin).
|
|
|
|
This should fix the installation problems and the Nix UML should boot
|
|
flawlessly.
|
|
|
|
|
|
Nix UML and 2.6 kernel
|
|
|
|
Installing the current Nix UML packages with a 2.4 kernel on a 2.6
|
|
kernel based host system will most likely fail. Linux kernel 2.6 uses NPTL
|
|
by default, but UML itself seems to be broken somewhat so halfway the system
|
|
seems to hang.
|
|
|
|
Installing a 2.6 based UML with Nix is not trivial and is not advised.
|
|
|
|
|
|
Using the Nix UML
|
|
|
|
By default, the Nix UML comes with very little configuration. Apart from the
|
|
networking information and mount information, there is nothing. One of the
|
|
first things to do is to add user and group information, otherwise a lot
|
|
of tools won't work. There are empty passwd, shadow and group files. Due
|
|
to some limitations in Nix it is only possible to modify the password file
|
|
as root.
|
|
|
|
- add a root user:
|
|
|
|
useradd root
|
|
|
|
- edit /etc/passwd and change the UID to 0 ("vim" is provided)
|
|
- add a root group:
|
|
|
|
groupadd root
|
|
|
|
|
|
Adding packages to the UML Nix installation
|
|
|
|
Packages can be added the the Nix UML installation by editing a few files.
|
|
The first file packages should be added to is 'pkgs.nix'. The other files
|
|
that should be edited all reside in the "boot" directory. In default.nix
|
|
the packages should be added as an argument (first line) and given as an
|
|
argument to the builder (line starting with "inherit"). In "builder.sh"
|
|
there is a sed expression which subsitutes all occurences of the names of
|
|
the packages in the files with the right value. If the programs that are
|
|
added need to be added to $PATH the file "env.sh" has to be edited and the
|
|
UML has to be recreated.
|
|
|
|
Another option would be to enable networking in the UML and use nix-pull to
|
|
get all the right packages, however this does not work yet out of the box.
|
|
A small trick is to symlink /bin/sh to the current version of "sh":
|
|
|
|
# cd /bin
|
|
# ln -s `which sh` sh
|
|
|
|
We're looking for a more permanent solution to fix this.
|