Give up on kexec for auto-upgrades

[jdreed]

Unattended kexec is mostly unusable on modern systems (or at least with the natty kernel). If things don't improve, we should download the kernel and initrd and sketch on grub and reboot that way. Note that this requires changing /etc/default/grub to use GRUB_DEFAULT=saved

[geofft]

I don't think you want GRUB_DEFAULT=saved, actually. That risks people booting into some other kernel (recovery kernel, old kernel, memtest) and the machine always booting into that kernel; see #968 and  LP:436936 for issues we've run into with this.

You only need GRUB_DEFAULT=saved for grub-reboot, and we can just add the kernel we want to boot to a fixed position, e.g., the first one and avoid grub-reboot entirely.

[jrjarvis]

/mit/jrjarvis/Public/athena-auto-upgrade

Went with the grub-reboot approach and put the kernel/initrd on athena-root.

Creates a new entry in grub.d for "auto-upgrade", modifies /etc/default/grub, grub-reboots into auto-upgrade to kick off the installer.

$ athena-auto-upgrade -d

mkdir -p /auto-upgrade
wget http://debathena.mit.edu/net-install/oneiric/i386/initrd.gz -O /auto-upgrade/initrd.gz
wget http://debathena.mit.edu/net-install/oneiric/i386/linux -O /auto-upgrade/linux
DEBUG: USING kargs=netcfg/get_hostname=helicon             netcfg/disable_dhcp=true             netcfg/get_domain=mit.edu             netcfg/get_nameservers="18.72.0.3 18.70.0.160"            netcfg/get_ipaddress=18.18.3.99             netcfg/get_netmask=255.255.0.0             netcfg/get_gateway=18.18.0.1             netcfg/confirm_static=true locale=en_US keyboard-configuration/layoutcode=us        interface=auto        url=http://18.9.60.73/installer/oneiric/debathena.preseed        debathena/pxetype=cluster --
cp /tmp/athena-auto-upgrade.27840.tmp /etc/grub.d/49_auto-upgrade
chmod 755 /etc/grub.d/49_auto-upgrade
perl -i.bak -pe s/^GRUB_DEFAULT=.*$/GRUB_DEFAULT=saved/ /etc/default/grub
perl -i.bak -pe s/^GRUB_CMDLINE_LINUX_DEFAULT=.*$/GRUB_CMDLINE="quiet panic=5"/ /etc/default/grub
/usr/sbin/grub-set-default 0
/usr/sbin/grub-reboot auto-upgrade
/usr/sbin/update-grub
/sbin/reboot

Note if something does fail during upgrade /etc/default/grub will be tainted.

[kaduk]

Replying to jrjarvis:

$ athena-auto-upgrade -d

mkdir -p /auto-upgrade
wget http://debathena.mit.edu/net-install/oneiric/i386/initrd.gz -O /auto-upgrade/initrd.gz
wget http://debathena.mit.edu/net-install/oneiric/i386/linux -O /auto-upgrade/linux
DEBUG: USING kargs=netcfg/get_hostname=helicon             netcfg/disable_dhcp=true             netcfg/get_domain=mit.edu             netcfg/get_nameservers="18.72.0.3 18.70.0.160"            netcfg/get_ipaddress=18.18.3.99             netcfg/get_netmask=255.255.0.0             netcfg/get_gateway=18.18.0.1             netcfg/confirm_static=true locale=en_US keyboard-configuration/layoutcode=us        interface=auto        url=http://18.9.60.73/installer/oneiric/debathena.preseed        debathena/pxetype=cluster --
cp /tmp/athena-auto-upgrade.27840.tmp /etc/grub.d/49_auto-upgrade
chmod 755 /etc/grub.d/49_auto-upgrade
perl -i.bak -pe s/^GRUB_DEFAULT=.*$/GRUB_DEFAULT=saved/ /etc/default/grub
perl -i.bak -pe s/^GRUB_CMDLINE_LINUX_DEFAULT=.*$/GRUB_CMDLINE="quiet panic=5"/ /etc/default/grub
/usr/sbin/grub-set-default 0
/usr/sbin/grub-reboot auto-upgrade
/usr/sbin/update-grub
/sbin/reboot

Hmm, two successive perl -i.bak -pe s/foo/bar/ on /etc/default/grub may not be the greatest plan.

Note if something does fail during upgrade /etc/default/grub will be tainted.

tained as in have GRUB_DEFAULT=saved and/or GRUB_CMDLINE set, or something else?

[jdreed]

Keep in mind that athena-auto-upgrade should only ever be run on -cluster, so we should feel free to clobber /etc/default/grub in any way we like.

[jdreed]

OK, code tested now that we have a testing entry for Precise on alpha. Awaiting a build.

[jdreed]

auto-update 1.35 is in -dev.