Step 1 Cloning the Xen Ubuntu
Cloning the VM
cp ubuntu umlubuntu cp ubuntu.img umlubuntu.img
Have to change a bit the domU configuration file, a new domain name, different VNC port (5902) and different MAC address for the VM. the configuration file for umlubuntu domU look like this
kernel = "hvmloader" #kernel to be used builder='hvm' # memory = 1024 # memory allocated, this will overwrite the default value in dom0 name = "umlubuntu" #name of the VM acpi=1 # ACPI set to yes apic=1 # APIC set to yes vif = ['type=ioemu, bridge=eth2, mac=00:16:3E:00:00:03', 'type=ioemu, bridge=et$ disk = ['file:/home/vic/umlubuntu.img,hda,w','file:/home/vic/ubuntu-10.04.1-des$ device_model = '/usr/lib/xen/bin/qemu-dm' #define the device model boot="cd" # boot sequence, c = disk, d = cd vnc=1 #enable VNC on VM using the default port 5900 vncdisplay=2 on_poweroff = 'destroy' #on VM power off behaviour on_reboot = 'restart' #on VM reboot behaviour on_crash = 'restart' #on VM crash behaviour usbdevice='tablet'
Change the configuration of dhcp server
I add the following code to the dhcp ip assigning scheme to give my new umlubuntu domU a constant IP address.
host umlubuntu { hardware ethernet 00:16:3E:00:00:03; fixed-address 145.100.106.84; option routers 145.100.106.81; }
SSH to the new UMLUbuntu (with X)
As I installed already the SSH server in the previous ubuntu domU, so it is directly available. I can just ssh to it and start the installation of UML.
ssh vic@145.100.106.84
And we have to make the X environment remotely. So we can run X program from our workstation.
ssh -X vic@145.100.106.84
with the -X option. the remote X gedit works. If it is not working, it is mostly because the X11forwarding is not set to yes in the /etc/ssh/sshd_config
Step 2 Install UML
As instructed in the assignment, I install the UML package by using the following command.
sudo apt-get install user-mode-linux
I then ran the linux.uml to check if it works. It is installed but like stated in the assignment without a proper filesystem it will not work.
vic@vicubuntu:~$ linux.uml Locating the bottom of the address space ... 0x10000 Locating the top of the address space ... 0xc0000000 Core dump limits : soft - 0 hard - NONE Checking that ptrace can change system call numbers...OK Checking syscall emulation patch for ptrace...OK Checking advanced syscall emulation patch for ptrace...OK Checking for tmpfs mount on /dev/shm...OK Checking PROT_EXEC mmap in /dev/shm/...OK Checking for the skas3 patch in the host: - /proc/mm...not found: No such file or directory - PTRACE_FAULTINFO...not found - PTRACE_LDT...not found UML running in SKAS0 mode Adding 32485376 bytes to physical memory to account for exec-shield gap Initializing cgroup subsys cpuset Linux version 2.6.32.15+drm33.5 (root@palmer) (gcc version 4.4.3 (Ubuntu 4.4.3-4ubuntu5) ) #2 Tue Aug 17 06:09:58 UTC 2010 () Built 1 zonelists in Zone order, mobility grouping on. Total pages: 15997 Kernel command line: root=98:0 PID hash table entries: 256 (order: -2, 1024 bytes) Dentry cache hash table entries: 8192 (order: 3, 32768 bytes) Inode-cache hash table entries: 4096 (order: 2, 16384 bytes) allocated 322460 bytes of page_cgroup please try 'cgroup_disable=memory' option if you don't want memory cgroups Memory: 26700k available SLUB: Genslabs=13, HWalign=16, Order=0-3, MinObjects=0, CPUs=1, Nodes=1 Hierarchical RCU implementation. NR_IRQS:15 Calibrating delay loop... 1477.83 BogoMIPS (lpj=7389184) Mount-cache hash table entries: 512 Initializing cgroup subsys ns Initializing cgroup subsys cpuacct Initializing cgroup subsys memory Initializing cgroup subsys devices Initializing cgroup subsys freezer Checking for host processor cmov support...Yes Checking that host ptys support output SIGIO...Yes Checking that host ptys support SIGIO on close...No, enabling workaround Using 2.6 host AIO NET: Registered protocol family 16 bio: create slab <bio-0> at 0 Switching to clocksource itimer NET: Registered protocol family 2 IP route cache hash table entries: 1024 (order: 0, 4096 bytes) TCP established hash table entries: 2048 (order: 2, 16384 bytes) TCP bind hash table entries: 2048 (order: 1, 8192 bytes) TCP: Hash tables configured (established 2048 bind 2048) TCP reno registered NET: Registered protocol family 1 IRQ 9/mconsole: IRQF_DISABLED is not guaranteed on shared IRQs mconsole (version 2) initialized on /home/vic/.uml/jrYIfH/mconsole Checking host MADV_REMOVE support...OK Mapper v0.1 mmapper_init - find_iomem failed UML Watchdog Timer Host TLS support detected Detected host type: i386 (GDT indexes 6 to 9) VFS: Disk quotas dquot_6.5.2 Dquot-cache hash table entries: 1024 (order 0, 4096 bytes) squashfs: version 4.0 (2009/01/31) Phillip Lougher JFS: nTxBlock = 209, nTxLock = 1672 SGI XFS with ACLs, security attributes, realtime, large block/inode numbers, no debug enabled SGI XFS Quota Management subsystem Btrfs loaded msgmni has been set to 52 alg: No test for stdrng (krng) io scheduler noop registered io scheduler anticipatory registered io scheduler deadline registered io scheduler cfq registered (default) SoftDog: cannot register miscdev on minor=130 (err=-16) TCP cubic registered NET: Registered protocol family 17 Initialized stdio console driver Console initialized on /dev/tty0 console [tty0] enabled Initializing software serial port version 1 console [mc-1] enabled Couldn't stat "root_fs" : err = 2 Failed to initialize ubd device 0 :Couldn't determine size of device's file registered taskstats version 1 VFS: Cannot open root device "98:0" or unknown-block(98,0) Please append a correct "root=" boot option; here are the available partitions: Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(98,0) 0b86bf08: [<083cb1c9>] panic+0x4d/0xfc 0b86bf24: [<08049a36>] mount_block_root+0x200/0x293 0b86bf68: [<081139c7>] sys_mknod+0x27/0x30 0b86bf7c: [<08049b24>] mount_root+0x5b/0x60 0b86bf90: [<08049c6e>] prepare_namespace+0x145/0x181 0b86bfa8: [<080491b0>] kernel_init+0xe9/0xf5 0b86bfbc: [<080898d0>] run_kernel_thread+0x30/0x50 0b86bfd8: [<080898bf>] run_kernel_thread+0x1f/0x50 0b86bfe4: [<0805ff9f>] new_thread_handler+0x6f/0xa0 0b86bfe8: [<080490c7>] kernel_init+0x0/0xf5 EIP: 0073:[<00b81422>] CPU: 0 Not tainted ESP: 007b:bfb46bc8 EFLAGS: 00000246 Not tainted EAX: 00000000 EBX: 00000753 ECX: 00000013 EDX: 00000753 ESI: 0000074f EDI: bfb46c48 EBP: 0000002d DS: 007b ES: 007b 0b86bee4: [<080b5bf1>] notifier_call_chain+0x41/0x60 0b86bf08: [<083cb1e5>] panic+0x69/0xfc 0b86bf24: [<08049a36>] mount_block_root+0x200/0x293 0b86bf68: [<081139c7>] sys_mknod+0x27/0x30 0b86bf7c: [<08049b24>] mount_root+0x5b/0x60 0b86bf90: [<08049c6e>] prepare_namespace+0x145/0x181 0b86bfa8: [<080491b0>] kernel_init+0xe9/0xf5 0b86bfbc: [<080898d0>] run_kernel_thread+0x30/0x50 0b86bfd8: [<080898bf>] run_kernel_thread+0x1f/0x50 0b86bfe4: [<0805ff9f>] new_thread_handler+0x6f/0xa0 0b86bfe8: [<080490c7>] kernel_init+0x0/0xf5 Segmentation fault
Step 3 Setup UML instance
Compile Busybox 1.18.2
I downloaded busybox source from the official website and install the necessary compiler and library and built it.
sudo apt-get install build-essentials libncurses-dev cd /home/vic/Downloads/busybox-1.18.2/ make menuconfig make ## To verify the compiled object: busybox ## vic@vicubuntu:~/Downloads/busybox-1.18.2$ ldd busybox linux-gate.so.1 => (0x00876000) libm.so.6 => /lib/tls/i686/cmov/libm.so.6 (0x003ae000) libc.so.6 => /lib/tls/i686/cmov/libc.so.6 (0x00638000) /lib/ld-linux.so.2 (0x00932000)
Copy busybox to the bin folder of root folder prepared for the UML instance and create the symbol link
./busybox --help | grep 'Currently defined functions:' -A30 | grep '^\s.*,' | tr , '\n' | xargs -n1 -i{} ln -s busybox {}
This get what the busybox can do from the help function of busybox and recursively add all of them as symbol links to busybox.
Error
I got kernal panic because of the error below
uml /bin/init: error while loading shared libraries: libm.so.6: cannot open shared object file: No such file or directory
The dynamic loaded module is missing for the busybox I previously complied. Got hint from Cosmin that a static build will solve the problem as no module lookup is needed. so I recompiled the busybox with static option selected during the make menuconfig . Afterward, I can start UML without problem.
make the file system for UML
I created under /home/vic a folder named uml to be used as the root of the UML instance. Here is my folder structure under uml folder
vic@vicubuntu:~/uml$ ls -R .: bin dev etc lib mnt proc sbin usr var ./bin: busybox ./dev: ./etc: fstab init.d inittab ./etc/init.d: rcS ./lib: ./mnt: ./proc: ./sbin: ./usr: ./var: log ./var/log:
This will copy all the device from the host (Xen ubuntu) to the UML instance.
cp -vdpR /dev/* /home/vic/uml/dev/
The create fstab and inittab
vic@vicubuntu:~$ cat ./uml/etc/fstab proc /proc proc defaults 0 0 vic@vicubuntu:~/uml/etc$ cat inittab ::sysinit:/etc/init.d/rcS ::askfirst:-/bin/sh
The inittab will execute the rcS during the initialization and the rcS should try to mount everything in the fstab. The rcS should be +x
vic@vicubuntu:~/uml/etc/init.d$ cat rcS #!/bin/sh mount -a vic@vicubuntu:~/uml/etc/init.d$ chmod +x rcS
Step 4 Run the UML instance
vic@vicubuntu:~/uml/bin$ linux.uml rootfstype=hostfs rootflags=/home/vic/uml/ rw / # / # ls bin dev etc lib mnt proc sbin usr var / #
I am finally in the UML instance (single mode) next step, make it multiple mode
Error
The eth0 is missing from the UML instance. I got the error number = 13. Check a lot on google found that it is “permission denied” on accessing the switch file /home/vic/umlubuntu/sw1.ctl .
Obviously, in order to start the switch in daemon mode (-daemon option) , I have to “sudo” the uml_switch. So the connector owner is root, and I start the UML instance use my own account, that is why I cannot connect to the switch hence the eth0 will not appear. When I change to sudo the uml instance, the eth0 showed up.
/ # ifconfig -a
eth0 Link encap:Ethernet HWaddr A2:F4:38:6A:8A:89
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:5
lo Link encap:Local Loopback
LOOPBACK MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Step 5 Simple network
I start the UMLA and UMLB
#start UMLA sudo linux.uml umlid=umla rootfstype=hostfs rootflags=/home/vic/uml/ rw eth0=daemon,,unix,/home/vic/umlswitch/sw1.ctl #start UMLB sudo linux.uml umlid=umlb rootfstype=hostfs rootflags=/home/vic/uml/ rw eth0=daemon,,unix,/home/vic/umlswitch/sw1.ctl
Configuration on UMLA
/ # ifconfig -a
eth0 Link encap:Ethernet HWaddr 16:03:7F:2D:F8:74
BROADCAST MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:5
lo Link encap:Local Loopback
LOOPBACK MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
/ # ifconfig eth0 10.0.0.1/8 up
/ # ifconfig lo up
Configuration on UMLB
/ # ifconfig eth0 10.0.0.2/8 up
/ # ifconfig lo up
/ # ifconfig -a
eth0 Link encap:Ethernet HWaddr 52:8F:EC:4D:51:7B
inet addr:10.0.0.2 Bcast:10.255.255.255 Mask:255.0.0.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:5
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Now the simple network is fully functional
ping from UMLA to UMLB
/ # ping 10.0.0.2 PING 10.0.0.2 (10.0.0.2): 56 data bytes 64 bytes from 10.0.0.2: seq=0 ttl=64 time=12.136 ms 64 bytes from 10.0.0.2: seq=1 ttl=64 time=0.172 ms 64 bytes from 10.0.0.2: seq=2 ttl=64 time=0.173 ms 64 bytes from 10.0.0.2: seq=3 ttl=64 time=0.167 ms ^C --- 10.0.0.2 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max = 0.167/3.162/12.136 ms
ping from UMLB to UMLA
/ # ping 10.0.0.1 PING 10.0.0.1 (10.0.0.1): 56 data bytes 64 bytes from 10.0.0.1: seq=0 ttl=64 time=0.236 ms 64 bytes from 10.0.0.1: seq=1 ttl=64 time=0.169 ms 64 bytes from 10.0.0.1: seq=2 ttl=64 time=0.170 ms 64 bytes from 10.0.0.1: seq=3 ttl=64 time=0.165 ms ^C --- 10.0.0.1 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max = 0.165/0.185/0.236 ms
