My Linode is a Gentoo box. Which means tons of Portage, tons of Kernel source, etc. I would like to install FUSE, and use a Compressed FUSE FS Mount to store Portage and the Kernel Sources. I chose Gentoo because I wanted all my binaries as small and optomized as possible for my 'Node (I'm doing streaming audio and a bit of transcoding, so it needs to be streamlined)... but I'm not concerned about Portage "performance." If it takes a bit longer to emerge a program, that's a price I'll happily pay for Portage taking half it's normal space on the disk (leaving more room for audio).

But, when I try to emerge sys-fs/fuse, I get:

 * Could not find a usable .config in the kernel source directory.
 * Please ensure that /usr/src/linux points to a configured set of Linux sources.
 * If you are using KBUILD_OUTPUT, please set the environment var so that
 * it points to the necessary object directory so that it might find .config.
 *
 * ERROR: sys-fs/fuse-2.7.4 failed.
 * Call stack:
 *               ebuild.sh, line   49:  Called pkg_setup
 *       fuse-2.7.4.ebuild, line   29:  Called linux-mod_pkg_setup
 *        linux-mod.eclass, line  579:  Called linux-info_pkg_setup
 *       linux-info.eclass, line  846:  Called check_extra_config
 *       linux-info.eclass, line  698:  Called linux_chkconfig_present 'FUSE_FS'
 *       linux-info.eclass, line  277:  Called require_configured_kernel
 *       linux-info.eclass, line  264:  Called die
 * The specific snippet of code:
 *              die "Kernel not configured; no .config found in ${KV_OUT_DIR}"
 *  The die message:
 *   Kernel not configured; no .config found in /usr/src/linux
 *
 * If you need support, post the topmost build error, and the call stack if relevant.
 * A complete build log is located at '/var/tmp/portage/sys-fs/fuse-2.7.4/temp/build.log'.
 * The ebuild environment file is located at '/var/tmp/portage/sys-fs/fuse-2.7.4/temp/die.env'.

I remember having this problem before, wayback when I was running a Linode in the past. I'm using the stock Kernel with the stock Gentoo image from Linode, but apparently a .config isn't provided with the image, and therefore trying to get fuse installed won't work.

I might be missing a step, this is the first time I've tried to get FUSE to work on Gentoo.

(Also note: Gentoo helpfully installed gentoo-sources for the kernel source; I think there's a xen specific kernel sources available, but didn't want to interrupt Gentoo while it was doing it's thing. Do I need to do anything here?)

.config files for all the kernels we supply can be found in the source tarballs we distribute in this directory. I'm not sure where you'd tell Gentoo to find that, but if you can figure it out you can use those .configs.

Kernel not configured; no .config found in /usr/src/linux

...sounds promising.

_________________
Disclaimer: I am no longer employed by Linode; opinions are my own alone.

If you are using the Linode kernel, then I would suggest downloading the linode kernel sources from the link that Jed supplied and extracting them to /usr/src. Then symlink to /usr/src/linux as you would with the normal gentoo sources. In the past I have needed to do a "make prepare" on the kernel when I had similar problems, but I'm not sure if you'll need that or not.

Another option if you are on xen is to use pv-grub and then you can build and run the stock gentoo kernel. See here and here.