Linode Forum

[pxtmc]

Hi, currently I'm using a Debian 5.0 with the 2.6.18.8-x86_64-linode10 kernel. I tried to upgrade it selecting the image 2.6.32-x86_64-linode11 (paravirt) in the linode manager, but I noticed a strange behaviour:
- with the free -m command it showed less RAM than the total amount, exactly 512 instead of 540MB. With the 2.6.18.8 kernel, free -m showed exactly 540 MB
- showing at the CPU graph, it's always over a 0,5-0,7%... nothing incredible, but with the 2.6.18.8 when the node was doing nothing, the CPU graph was at 0%... it's a little bit annoying.

So, in order to upgrade the kernel I ran the command aptitude search linux-image and this is the result:
[wopr  ~] aptitude search linux-image
v linux-image -
v linux-image-2.6 -
p linux-image-2.6-amd64 - Linux 2.6 image on AMD64
p linux-image-2.6-openvz-amd64 - Linux 2.6 image on AMD64, OpenVZ support
p linux-image-2.6-vserver-amd64 - Linux 2.6 image on AMD64, Linux-VServer su
p linux-image-2.6-xen-amd64 - Linux 2.6 image on AMD64, oldstyle Xen sup
p linux-image-2.6.26-1-amd64 - Linux 2.6.26 image on AMD64
p linux-image-2.6.26-1-openvz-amd - Linux 2.6.26 image on AMD64, OpenVZ suppor
p linux-image-2.6.26-1-vserver-am - Linux 2.6.26 image on AMD64, Linux-VServer
p linux-image-2.6.26-1-xen-amd64 - Linux 2.6.26 image on AMD64, oldstyle Xen
p linux-image-2.6.26-2-amd64 - Linux 2.6.26 image on AMD64
p linux-image-2.6.26-2-openvz-amd - Linux 2.6.26 image on AMD64, OpenVZ suppor
p linux-image-2.6.26-2-vserver-am - Linux 2.6.26 image on AMD64, Linux-VServer
p linux-image-2.6.26-2-xen-amd64 - Linux 2.6.26 image on AMD64, oldstyle Xen
p linux-image-amd64 - Linux image on AMD64
p linux-image-openvz-amd64 - Linux image on AMD64, OpenVZ support
p linux-image-vserver-amd64 - Linux image on AMD64, Linux-VServer suppor
p linux-image-xen-amd64 - Linux image on AMD64, oldstyle Xen support
[wopr  ~]

So, which one should I install among the four linux-image-2.6.26-2*?
Probably the "oldstyle Xen" one?
And another question: If I upgraded the kernel, once the linode should have to reboot, it would be replaced with the kernel indicated in my linode profile (2.6.18.8....)?

I hope to have been clear...

Thank you.

[hybinet]

You'd need pv-grub

http://library.linode.com/advanced/pv-grub-howto

[pxtmc]

Thank you.

[mnordhoff]

This doesn't seem like good justification to go through the trouble of using a custom kernel...

pxtmc wrote: - with the free -m command it showed less RAM than the total amount, exactly 512 instead of 540MB. With the 2.6.18.8 kernel, free -m showed exactly 540 MB

That's probably normal, just the kernel not including its memory or initrd memory or somesuch in the figure. My 32-bit 540 shows 526 MB of RAM total; your 512 MB figure is probably just a coincidence (and a bit lower than mine because it's 64-bit).

pxtmc wrote: - showing at the CPU graph, it's always over a 0,5-0,7%... nothing incredible, but with the 2.6.18.8 when the node was doing nothing, the CPU graph was at 0%... it's a little bit annoying.

Eh. I've heard of that, but don't remember the details. It's really not very much CPU anyway...

pxtmc wrote: And another question: If I upgraded the kernel, once the linode should have to reboot, it would be replaced with the kernel indicated in my linode profile (2.6.18.8....)?

I'm not sure what you mean. Unless you're using pv-grub, Xen complete ignores your /boot directory. You can put whatever you want in it, including other kernels. It does not dump a copy of Linode's kernel in /boot.

[Guspaz]

I'd agree, that's not really a good reason to be messing with custom kernels.

[pxtmc]

Sorry, I don't understand: are you suggesting me to install a newer kernel (via aptitude install...) or to maintain the "linode kernel"?
If the right way was the first one (keep kernel upgraded) which one should I choose?
Infact aptitutude search linux-image returns four possible linux-image... have I to install the last one, linux-image-2.6.26-2-xen-amd64 - Linux 2.6.26 image on AMD64, oldstyle Xen?

Thank you

[glg]

OP, what are you trying to do. You're asking a lot of questions, but it's completely unclear what your goal is.

[pxtmc]

Ok, I try to explain with my poor english:

My node is running a Debian 5.0 x64 with the "linode" kernel 2.6.18.8.

My goal is to keep my node always up to date, software and system.
Infact I think that an up-to-date system is more secure than a not updated one... isn't it?

So, if for the installed software I periodically run aptitude update/upgrade and manually update third-party software, for the system (the linux kernel) I don't know what the linode platform let me do to keep the kernel updated... I read just few hours ago about the pv_grub.
I think it can be the right way: install grub, the new linux-image and configure my node to use pv_grub.

My doubts are:
- linux-image-xen-amd64 is the right kernel to install?
- in your experience, do you think it's all wasted job, meaning that the linode kernel ( 2.6.18.8 ) is secure enough that it doesn't require this "manual" upgrade?

I hope to have clarified my goals and doubts... (I know, I need an advanced english course :lol: )

[mnordhoff]

pxtmc wrote: - linux-image-xen-amd64 is the right kernel to install?

Given the "oldstyle Xen" description, I would guess that it uses the old Xen patches instead of pv_ops, making it the wrong kernel to install.

pxtmc wrote: - in your experience, do you think it's all wasted job, meaning that the linode kernel ( 2.6.18.8 ) is secure enough that it doesn't require this "manual" upgrade?

Yes, I think it's a waste of effort. Linode is not run by idiots. They do backport security patches to the 2.6.18 kernels when necessary, and the new pv_ops kernels are, well, new.

To keep the kernel up-to-date, set your configuration profile to use "Latest 2.6 Stable" or "Latest 2.6 Paravirt" and reboot whenever a new kernel comes out. Even ignoring the pv-grub stuff, that's still easier than maintaining Debian's kernel with aptitude.

[pxtmc]

Perfect... I think your post can close the argument!

Thank you all.