User talk:Jch/Starting AL from network
Starting AL from network
As it does not seems possible to start qemu with a virtual USB key *and* a virtual HDD attached to the VM. Let's try something different: to start AL from the network and mount the HDD later on...
Usually this kind of setup needs
- a DHCP server to get an IP address and the location of the TFTP server
- a TFTP server to download the kernel and tje root file system to boot from
- a NFS server or a HTTP one to get the overlay used to configure the machine
- a NFS server to share files with others
- a NBD server to get his own block devices as storage
- a machine where to prepare initramfs
First, let's check what is vailable in AL and what is not...
- dhcpcd-6.6.7-r0
- tftp-hpa-5.2-r1
- nfs-utils-1.3.1-r2
- darkhttpd-1.10-r1
- nbd-3-10-r0
PXE_boot
We are trying to do something as in PXE_boot.
We did it on separate machine for each service. It forces us to deeply understand all interactions between processes.
But next one will be all-in-one KVM.
In current state we
umount /media/alpine
as last step of the boot procees and we are running with no tie.
dhcpd
192.168.1.1
with package dhcp from repo. Nothing special.
filename "pxelinux.0"; next-server 192.168.1.2;
and
# Disable RFC 2136 dynamic DNS updates.
ddns-update-style none;
# Define actions to take when leases are committed, released, or expired to
# accomplish dynamic DNS updates to djbdns. This does not use the RFC 2136
# update mechanism, because djbdns does not support it. However, it
# accomplishes the same thing.
# syntax "execute(cmd, arg, ...)"
### need to check if the two "on EVENT" must be nested or in sequence...
on commit {
execute ("/usr/local/bin/dns-update-djb",
"commit",
lcase (option host-name),
config-option domain-name,
binary-to-ascii (10, 8, ".", leased-address));
on release or expiry {
execute ("/usr/local/bin/dns-update-djb",
"release",
binary-to-ascii (10, 8, ".", leased-address));
}
}
with a custom /usr/local/bin/dns-update-djb script largely inspired from https://sites.google.com/site/dmoulding/dns-update-djb but adapted for a distant tinydns server and to the AL way.
tftp
192.168.1.2
tftp-hpa configured to serve some SYSLINUX files.
The config is in /etc/conf.d/in.tftpd
Then to issue:
rc-update add in.tftpd rc-service in.tftpd start
We serve from /var/tftpboot.
We add to temporary install the syslinux apk to get pxelinix.0 and other libs needed.
We did prepare a "pxerd" initramfs file with virtio_net.ko, dhcp and nfs included; made sure loop and squashfs are included.
pxelinux.cfg/default looks like
PROMPT 0 TIMEOUT 3 default alpine LABEL alpine LINUX alpine/vmlinuz-grsec INITRD alpine/pxerd APPEND ip=dhcp alpine_dev=nfs:192.168.1.3:/srv/boot/alpine modloop=/boot/grsec.modloop.squashfs nomodeset quiet apkovl=http://192.168.1.4/localhost.apkovl.tar.gz #APPEND modloop=http:/192.168.1.4/grsec.modloop.squashfs #APPEND apkovl=http://192.168.1.4/localhost.apkovl.tar.gz # including the modloop hack #APPEND alpine_repo=http://repo-url
Modules are loaded
/ # lsmod Module Size Used by Not tainted nfsv3 22784 1 nfs 144376 2 nfsv3 lockd 71917 2 nfsv3,nfs sunrpc 225574 6 nfsv3,nfs,lockd af_packet 28735 0 sr_mod 13487 0 cdrom 40424 1 sr_mod pata_acpi 3326 0 ata_piix 25601 0 ata_generic 3554 0 libata 181955 3 pata_acpi,ata_piix,ata_generic virtio_net 19684 0 scsi_mod 113710 2 sr_mod,libata virtio_pci 6485 0 virtio 4933 2 virtio_net,virtio_pci virtio_ring 9161 2 virtio_net,virtio_pci squashfs 25893 1 loop 18243 2
Network is up
/ # ifconfig eth0 Link encap:Ethernet HWaddr 52:54:33:B0:C2:D2 inet addr:192.168.1.108 Bcast:0.0.0.0 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:322 errors:0 dropped:0 overruns:0 frame:0 TX packets:2 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:20514 (20.0 KiB) TX bytes:684 (684.0 B)
but modloop does not load This patch fix this issue (hope to see it mainstream soon)
localhost:~# diff /etc/init.d/modloop modloop.new
--- /etc/init.d/modloop
+++ modloop.new
@@ -32,7 +32,7 @@
local search_dev="$1" fstab="$2"
local dev mnt fs mntopts chk
case "$search_dev" in
- UUID=*|LABEL=*|/dev/*);;
+ UUID=*|LABEL=*|/dev/*|nfs);;
*) search_dev=/dev/$search_dev;;
esac
local search_real_dev=$(resolve_dev $search_dev)
@@ -49,6 +49,10 @@
fi
done
done
+ if [ "$fs" = "$search_dev" ]; then
+ echo "$mnt"
+ return
+ fi
done < $fstab 2>/dev/null
}
References
http://www.syslinux.org/wiki/index.php/PXELINUX
nfs
192.168.1.3
see http://wiki.alpinelinux.org/wiki/User_talk:Jch#NFS_bug_study
It is now working with http://dev.alpinelinux.org/~clandmeter/rpcbind-0.2.3_rc2-r0.apk
We serve the content of an usb key (iso) in ro as
/srv/boot/alpine *(ro,no_root_squash,no_subtree_check)
http
192.168.1.4
With package Darkhttpd from repo serving from /var/tftpboot/ to serve files needed to boot (kernel, rootfs, apkovl.tar.gz)
nbd
192.168.1.5
I really would like to have xnbd-server in AL. nbd-3.1.0 was just added to edge/testing repo; need to try it in real situation...
For now, we have a qcow2 debian image added to the apkovl with lbu add; lbu ci.
This image is used to launch a first KVM with /dev/mdX as second drive.
In turn, inside the KVM, vdb is used to define a lvm2 volume.
The LV are published with xnbd-server.
Later on, the same KVM will be able to connect to RBD device and re-publish it as NBD.
xnbd-server allows live migration of Block Devices while live. And has a powerfull proxy mode.
All other KVM are running from FS accessed trough NBD from such SAN. Even other SAN.
As soon as those KVM-NBD are up, they may be used to launch others or to provide datastores.
We put that image on every USB key we use along with mdadm and OpenVSwitch (and collectd).
dns
192.168.1.6
tinydns from repo with split-dns config.