Today is a nice milestone. For the first time my server is "in the cloud", and yet I have full control over the kernel it is running.
While it should be possible to do this with Xen, I never found a host who would. So for the three years since I got rid of colocated physical hardware, I was constantly nagging my Xen hosters to update their kernels, often to fix security issues. And I sometimes struggled with things like udev that needed a newer kernel. Most importantly it just didn't feel right for "my" server to not run my kernel. Even though in this modern day, "my" server is just a fever dream of bigger computer. I'm infected with the Sovereign Computing meme.
KVM probably makes this easier than does Xen. What Steve has set up at kvm-hosting.org is a great example and template for providing a small group with great hosting at a very fair price, with full control, and an excellent interface.
It's the little things, like being able to view the my neighboring
guests' virtial machines in top, that I really like.
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 2841 joey 20 0 1637m 1.0g 3152 S 7 13.2 48:27.20 kvm 6606 steve 20 0 1365m 1.0g 3540 S 2 13.2 9:29.52 kvm 2888 cernio 20 0 1269m 284m 3152 R 1 3.6 4:08.57 kvm 2800 ore2 20 0 754m 521m 3152 S 0 6.6 4:35.68 kvm
This all feels sorta science fictional when I step back and look at it.
notes for kernel setup on kvm-hosting.org
I want to be able to install regular Debian kernel packages. In these
packages, the virtio drivers are modules, and need to be manually added to
an initrd. So first edit /etc/initramfs-tools/modules and add the below
to it, then run update-initramfs -k all -u to rebuild the initrd. BTW,
some of these modules may not really be necessary.
virtio_blk virtio_console virtio_pci virtio_net virtio_balloon virtio-rng
Then edit /etc/kernel-img.conf to configure the kernels to add
a symlink to the latest version in /boot. This way, kvm-shell can be
configured to boot the latest kernel automatically.
do_symlinks = yes link_in_boot = yes
And here is a hook that rsyncs /boot, sending kernels and initrds to
kvm-hosting, so its interface will let me boot them. This was put in
/etc/initramfs-tools/hooks/kvmhostingrsync and made executable.
#!/bin/sh # Use --copy-links so the symlinks to the current # kernel and initrd are selectable in kvm-shell. # # Use --delete because I like living dangerously. :) rsync --copy-links --delete -vazr /boot/ kernels.kvm-hosting.net::joey-kernels/