Diff for /wikisrc/ports/xen/howto.mdwn between versions 1.157 and 1.167

version 1.157, 2018/08/27 16:54:42 version 1.167, 2019/12/17 20:59:09
Line 33  architecture, with installing NetBSD on  Line 33  architecture, with installing NetBSD on 
 installing software from pkgsrc.  See also the [Xen  installing software from pkgsrc.  See also the [Xen
 website](http://www.xenproject.org/).  website](http://www.xenproject.org/).
   
 This HOWTO attempts to address both the case of running a NetBSD dom0  [[!toc]]
 on hardware and running domUs under it (NetBSD and other), and also  
 running NetBSD as a domU in a VPS.  
   
 Versions and Support  #Versions and Support
 ====================  
   
 In NetBSD, Xen is provided in pkgsrc, via matching pairs of packages  In NetBSD, Xen is provided in pkgsrc, via matching pairs of packages
 xenkernel and xentools.  We will refer only to the kernel versions,  xenkernel and xentools.  We will refer only to the kernel versions,
Line 48  matching versions. Line 45  matching versions.
 Versions available in pkgsrc:  Versions available in pkgsrc:
   
 [[!table data="""  [[!table data="""
 Xen Version     |Package Name   |Xen CPU Support        |EOL'ed By Upstream  Xen Version     |Package Name   |Xen CPU Support        |xm?    |EOL'ed By Upstream
 4.2             |xenkernel42    |32bit, 64bit           |Yes  4.2             |xenkernel42    |i386 x86_64            |yes    |Yes
 4.5             |xenkernel45    |64bit                  |Yes  4.5             |xenkernel45    |x86_64                 |       |Yes
 4.6             |xenkernel46    |64bit                  |Partially  4.6             |xenkernel46    |x86_64                 |       |Yes
 4.8             |xenkernel48    |64bit                  |No  4.8             |xenkernel48    |x86_64                 |       |Yes
 4.11            |xenkernel411   |64bit                  |No  4.11            |xenkernel411   |x86_64                 |       |No
 """]]  """]]
   
 See also the [Xen Security Advisory page](http://xenbits.xen.org/xsa/).  See also the [Xen Security Advisory page](http://xenbits.xen.org/xsa/).
Line 66  dom0  |No Line 63  dom0  |No
 domU            |Yes  domU            |Yes
 """]]  """]]
   
 Note: NetBSD support is called XEN3. However, it does support Xen 4,  Note: NetBSD support is called XEN3.  However, it does support Xen 4,
 because the hypercall interface has remained identical.  because the hypercall interface has remained identical.
   
   Older Xen had a python-based management tool called xm, now replaced
   by xl.  xm is obsolete, but 4.2 remains in pkgsrc because migrating
   from xm to xl is not always trivial, and because 4.2 is the last
   version to run on an i386 dom0.
   
 Architecture  Architecture
 ------------  ------------
   
 Xen itself runs on x86_64 hardware.  Xen 4.5 and later runs on x86_64 hardware (the NetBSD amd64 port).
   Xen 4.2 can in theory use i386 hardware, but we do not have
   recent reports of success.
   
 The dom0 system, plus each domU, can be either i386PAE or amd64.  The dom0 system, plus each domU, can be either i386PAE or amd64.
 i386 without PAE is not supported.  i386 without PAE is not supported.
   
 The standard approach is to use NetBSD/amd64 for the dom0.  The standard approach is to use NetBSD/amd64 for the dom0.
   
 To use an i386PAE dom0, one must build or obtain a 64bit Xen kernel and  To use an i386PAE dom0 (other than on 4.2), one must build or obtain a
 install it on the system.  64bit Xen kernel and install it on the system.
   
 For domUs, i386PAE is considered as  For domUs, i386PAE is considered as
 [faster](https://lists.xen.org/archives/html/xen-devel/2012-07/msg00085.html)  [faster](https://lists.xen.org/archives/html/xen-devel/2012-07/msg00085.html)
 than amd64.  than amd64.
   
 NetBSD as a dom0  # Creating a dom0
 ================  
   
 NetBSD can be used as a dom0 and works very well.  The following  
 sections address installation, updating NetBSD, and updating Xen.  
   
 Note that it doesn't make sense to talk about installing a dom0 OS  In order to install a NetBSD as a dom0, one must first install a normal
 without also installing Xen itself.  We first address installing  NetBSD system, and then pivot the install to a dom0 install by changing
 NetBSD, which is not yet a dom0, and then adding Xen, pivoting the  the kernel and boot configuration.
 NetBSD install to a dom0 install by just changing the kernel and boot  
 configuration.  
   
 In 2018-05, trouble booting a dom0 was reported with 256M of RAM: with  In 2018-05, trouble booting a dom0 was reported with 256M of RAM: with
 512M it worked reliably.  This does not make sense, but if you see  512M it worked reliably.  This does not make sense, but if you see
 "not ELF" after Xen boots, try increasing dom0 RAM.  "not ELF" after Xen boots, try increasing dom0 RAM.
   
 Styles of dom0 operation  
 ------------------------  
   
 There are two basic ways to use Xen.  The traditional method is for  
 the dom0 to do absolutely nothing other than providing support to some  
 number of domUs.  Such a system was probably installed for the sole  
 purpose of hosting domUs, and sits in a server room on a UPS.  
   
 The other way is to put Xen under a normal-usage computer, so that the  
 dom0 is what the computer would have been without Xen, perhaps a  
 desktop or laptop.  Then, one can run domUs at will.  
   
 Installation of NetBSD  Installation of NetBSD
 ----------------------  ----------------------
   
Line 125  Installation of Xen Line 111  Installation of Xen
   
 We will consider that you chose to use Xen 4.8, with NetBSD/amd64 as  We will consider that you chose to use Xen 4.8, with NetBSD/amd64 as
 dom0. In the dom0, install xenkernel48 and xentools48 from pkgsrc.  dom0. In the dom0, install xenkernel48 and xentools48 from pkgsrc.
 Ensure that your packages are recent.  
   
 Once this is done, install the Xen kernel itself:  Once this is done, install the Xen kernel itself:
   
Line 133  Once this is done, install the Xen kerne Line 118  Once this is done, install the Xen kerne
 # cp /usr/pkg/xen48-kernel/xen.gz /  # cp /usr/pkg/xen48-kernel/xen.gz /
 """]]  """]]
   
 Then, place a NetBSD XEN3_DOM0 kernel in the `/` directory, copied from  Then, place a NetBSD XEN3_DOM0 kernel in the `/` directory. Such kernel
 `releasedir/amd64/binary/kernel/netbsd-XEN3_DOM0.gz` of a NetBSD build.  can either be compiled manually, or downloaded from the NetBSD FTP, for
   example at:
   
   [[!template id=programlisting text="""
   ftp.netbsd.org/pub/NetBSD/NetBSD-8.0/amd64/binary/kernel/netbsd-XEN3_DOM0.gz
   """]]
   
 Add a line to /boot.cfg to boot Xen:  Add a line to /boot.cfg to boot Xen:
   
Line 142  Add a line to /boot.cfg to boot Xen: Line 132  Add a line to /boot.cfg to boot Xen:
 menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=512M  menu=Xen:load /netbsd-XEN3_DOM0.gz console=pc;multiboot /xen.gz dom0_mem=512M
 """]]  """]]
   
 which specifies that the dom0 should have 512MB of ram, leaving the rest  This specifies that the dom0 should have 512MB of ram, leaving the rest
 to be allocated for domUs.  To use a serial console, use  to be allocated for domUs.  To use a serial console, use:
   
 [[!template id=filecontent name="/boot.cfg" text="""  [[!template id=filecontent name="/boot.cfg" text="""
 menu=Xen:load /netbsd-XEN3_DOM0.gz;multiboot /xen.gz dom0_mem=512M console=com1 com1=9600,8n1  menu=Xen:load /netbsd-XEN3_DOM0.gz;multiboot /xen.gz dom0_mem=512M console=com1 com1=9600,8n1
Line 158  itself uses (in this case, the serial po Line 148  itself uses (in this case, the serial po
   
 In an attempt to add performance, one can also add `dom0_max_vcpus=1 dom0_vcpus_pin`,  In an attempt to add performance, one can also add `dom0_max_vcpus=1 dom0_vcpus_pin`,
 to force only one vcpu to be provided (since NetBSD dom0 can't use  to force only one vcpu to be provided (since NetBSD dom0 can't use
 more) and to pin that vcpu to a physical CPU.  more) and to pin that vcpu to a physical CPU. Xen has
   [many boot options](http://xenbits.xenproject.org/docs/4.8-testing/misc/xen-command-line.html),
 Xen has [many boot  
 options](http://xenbits.xenproject.org/docs/4.5-testing/misc/xen-command-line.html),  
 and other than dom0 memory and max_vcpus, they are generally not  and other than dom0 memory and max_vcpus, they are generally not
 necessary.  necessary.
   
 Now, reboot so that you are running a DOM0 kernel under Xen, rather  Copy the boot scripts into `/etc/rc.d`:
 than GENERIC without Xen.  
   
 Configuring Xen  
 ---------------  
   
 Now, you have a system that will boot Xen and the dom0 kernel, but not  
 do anything else special.  Make sure that you have rebooted into Xen.  
 There will be no domUs, and none can be started because you still have  
 to configure the dom0 daemons.  
   
 Since Xen 4.2, the tool which should be used is `xl`.  [[!template id=programlisting text="""
   # cp /usr/pkg/share/examples/rc.d/xen* /etc/rc.d/
   """]]
   
 For 4.1 and up, you should enable `xencommons`:  Enable `xencommons`:
   
 [[!template id=filecontent name="/etc/rc.conf" text="""  [[!template id=filecontent name="/etc/rc.conf" text="""
 xencommons=YES  xencommons=YES
 """]]  """]]
   
 Not enabling xencommons will result in a hang; it is necessary to hit `^C` on  Now, reboot so that you are running a DOM0 kernel under Xen, rather
 the console to let the machine finish booting:  than GENERIC without Xen.
   
 TODO: Recommend for/against xen-watchdog.  TODO: Recommend for/against xen-watchdog.
   
 After you have configured the daemons and either started them (in the  Once the reboot is done, use `xl` to inspect Xen's boot messages,
 order given) or rebooted, use `xl` to inspect Xen's boot messages,  
 available resources, and running domains.  For example:  available resources, and running domains.  For example:
   
 [[!template id=programlisting text="""  [[!template id=programlisting text="""
Line 292  Minor version upgrades are trivial.  Jus Line 272  Minor version upgrades are trivial.  Jus
 xenkernel version and copy the new xen.gz to `/` (where `/boot.cfg`  xenkernel version and copy the new xen.gz to `/` (where `/boot.cfg`
 references it), and reboot.  references it), and reboot.
   
 Unprivileged domains (domU)  #Unprivileged domains (domU)
 ===========================  
   
 This section describes general concepts about domUs.  It does not  This section describes general concepts about domUs.  It does not
 address specific domU operating systems or how to install them.  The  address specific domU operating systems or how to install them.  The
Line 311  the dom0.  NetBSD's /dev/random system w Line 290  the dom0.  NetBSD's /dev/random system w
 Config files  Config files
 ------------  ------------
   
 There is no good order to present config files and the concepts  See /usr/pkg/share/examples/xen/xlexample*
 surrounding what is being configured.  We first show an example config  for a small number of well-commented examples, mostly for running
 file, and then in the various sections give details.  
   
 See /usr/pkg/share/examples/xen/xmexample*,  
 for a large number of well-commented examples, mostly for running  
 GNU/Linux.  GNU/Linux.
   
 The following is an example minimal domain configuration file. The domU  The following is an example minimal domain configuration file. The domU
Line 340  are stored in files and Xen attaches the Line 315  are stored in files and Xen attaches the
 dom0 on domain creation.  The system treats xbd0 as the boot device  dom0 on domain creation.  The system treats xbd0 as the boot device
 without needing explicit configuration.  without needing explicit configuration.
   
 By default, `xl` looks for domain config files in `/usr/pkg/etc/xen`.  Note  By convention, domain config files are kept in `/usr/pkg/etc/xen`.  Note
 that "xl create" takes the name of a config file, while other commands  that "xl create" takes the name of a config file, while other commands
 take the name of a domain.  take the name of a domain.
   
 Examples of commands:  Examples of commands:
   
 [[!template id=programlisting text="""  [[!template id=programlisting text="""
 xl create foo  xl create /usr/pkg/etc/xen/foo
 xl console foo  xl console domU-id
 xl create -c foo  xl create -c /usr/pkg/etc/xen/foo
 xl shutdown foo  xl shutdown domU-id
 xl list  xl list
 """]]  """]]
   
Line 359  equivalent to pushing the power button;  Line 334  equivalent to pushing the power button; 
 power-press event and do a clean shutdown.  Shutting down the dom0  power-press event and do a clean shutdown.  Shutting down the dom0
 will trigger controlled shutdowns of all configured domUs.  will trigger controlled shutdowns of all configured domUs.
   
 domU kernels  
 ------------  
   
 On a physical computer, the BIOS reads sector 0, and a chain of boot  
 loaders finds and loads a kernel.  Normally this comes from the root  
 file system.  With Xen domUs, the process is totally different.  The  
 normal path is for the domU kernel to be a file in the dom0's  
 file system.  At the request of the dom0, Xen loads that kernel into a  
 new domU instance and starts execution. domU kernels can be anyplace.  
   
 Note that loading the domU kernel from the dom0 implies that boot  
 blocks, /boot, /boot.cfg, and so on are all ignored in the domU.  
 See the VPS section near the end for discussion of alternate ways to  
 obtain domU kernels.  
   
 CPU and memory  CPU and memory
 --------------  --------------
   
Line 392  use more memory temporarily. Line 352  use more memory temporarily.
 Virtual disks  Virtual disks
 -------------  -------------
   
 With the file/vnd style, typically one creates a directory,  In domU config files, the disks are defined as a sequence of 3-tuples:
 e.g. /u0/xen, on a disk large enough to hold virtual disks for all  
 domUs.  Then, for each domU disk, one writes zeros to a file that then   * The first element is "method:/path/to/disk". Common methods are
 serves to hold the virtual disk's bits; a suggested name is foo-xbd0     "file:" for a file-backed vnd, and "phy:" for something that is already
 for the first virtual disk for the domU called foo.  Writing zeros to     a device, such as an LVM logical volume.
 the file serves two purposes.  One is that preallocating the contents  
 improves performance.  The other is that vnd on sparse files has   * The second element is an artifact of how virtual disks are passed to
 failed to work.  TODO: give working/notworking NetBSD versions for     Linux, and a source of confusion with NetBSD Xen usage.  Linux domUs
 sparse vnd and gnats reference.  Note that the use of file/vnd for Xen     are given a device name to associate with the disk, and values like
 is not really different than creating a file-backed virtual disk for     "hda1" or "sda1" are common.  In a NetBSD domU, the first disk appears
 some other purpose, except that xentools handles the vnconfig     as xbd0, the second as xbd1, and so on.  However, xl demands a
 commands.  To create an empty 4G virtual disk, simply do     second argument.  The name given is converted to a major/minor by
      calling stat(2) on the name in /dev and this is passed to the domU.
         dd if=/dev/zero of=foo-xbd0 bs=1m count=4096     In the general case, the dom0 and domU can be different operating
      systems, and it is an unwarranted assumption that they have consistent
 Do not use qemu-img-xen, because this will create sparse file.  There     numbering in /dev, or even that the dom0 OS has a /dev.  With NetBSD
 have been recent (2015) reports of sparse vnd(4) devices causing     as both dom0 and domU, using values of 0x0 for the first disk and 0x1
 lockups, but there is apparently no PR.     for the second works fine and avoids this issue.  For a GNU/Linux
      guest, one can create /dev/hda1 in /dev, or to pass 0x301 for
 With the lvm style, one creates logical devices.  They are then used     /dev/hda1.
 similarly to vnds.  TODO: Add an example with lvm.  
   
 In domU config files, the disks are defined as a sequence of 3-tuples.  
 The first element is "method:/path/to/disk".  Common methods are  
 "file:" for file-backed vnd. and "phy:" for something that is already  
 a (TODO: character or block) device.  
   
 The second element is an artifact of how virtual disks are passed to  
 Linux, and a source of confusion with NetBSD Xen usage.  Linux domUs  
 are given a device name to associate with the disk, and values like  
 "hda1" or "sda1" are common.  In a NetBSD domU, the first disk appears  
 as xbd0, the second as xbd1, and so on.  However, xm/xl demand a  
 second argument.  The name given is converted to a major/minor by  
 calling stat(2) on the name in /dev and this is passed to the domU.  
 In the general case, the dom0 and domU can be different operating  
 systems, and it is an unwarranted assumption that they have consistent  
 numbering in /dev, or even that the dom0 OS has a /dev.  With NetBSD  
 as both dom0 and domU, using values of 0x0 for the first disk and 0x1  
 for the second works fine and avoids this issue.  For a GNU/Linux  
 guest, one can create /dev/hda1 in /dev, or to pass 0x301 for  
 /dev/hda1.  
   
 The third element is "w" for writable disks, and "r" for read-only   * The third element is "w" for writable disks, and "r" for read-only
 disks.     disks.
   
   Example:
   [[!template id=filecontent name="/usr/pkg/etc/xen/foo" text="""
   disk = [ 'file:/n0/xen/foo-wd0,0x0,w' ]
   """]]
   
 Note that NetBSD by default creates only vnd[0123].  If you need more  Note that NetBSD by default creates only vnd[0123].  If you need more
 than 4 total virtual disks at a time, run e.g. "./MAKEDEV vnd4" in the  than 4 total virtual disks at a time, run e.g. "./MAKEDEV vnd4" in the
Line 449  Virtual Networking Line 393  Virtual Networking
   
 Xen provides virtual Ethernets, each of which connects the dom0 and a  Xen provides virtual Ethernets, each of which connects the dom0 and a
 domU.  For each virtual network, there is an interface "xvifN.M" in  domU.  For each virtual network, there is an interface "xvifN.M" in
 the dom0, and in domU index N, a matching interface xennetM (NetBSD  the dom0, and a matching interface xennetM (NetBSD name) in domU index N.
 name).  The interfaces behave as if there is an Ethernet with two  The interfaces behave as if there is an Ethernet with two
 adapters connected.  From this primitive, one can construct various  adapters connected.  From this primitive, one can construct various
 configurations.  We focus on two common and useful cases for which  configurations.  We focus on two common and useful cases for which
 there are existing scripts: bridging and NAT.  there are existing scripts: bridging and NAT.
Line 477  The MAC address specified is the one use Line 421  The MAC address specified is the one use
 domain.  The interface in dom0 will use this address XOR'd with  domain.  The interface in dom0 will use this address XOR'd with
 00:00:00:01:00:00.  Random MAC addresses are assigned if not given.  00:00:00:01:00:00.  Random MAC addresses are assigned if not given.
   
 Sizing domains  
 --------------  
   
 Modern x86 hardware has vast amounts of resources.  However, many  
 virtual servers can function just fine on far less.  A system with  
 512M of RAM and a 4G disk can be a reasonable choice.  Note that it is  
 far easier to adjust virtual resources than physical ones.  For  
 memory, it's just a config file edit and a reboot.  For disk, one can  
 create a new file and vnconfig it (or lvm), and then dump/restore,  
 just like updating physical disks, but without having to be there and  
 without those pesky connectors.  
   
 Starting domains automatically  Starting domains automatically
 ------------------------------  ------------------------------
   
 To start domains foo at bar at boot and shut them down cleanly on dom0  To start domains `domU-netbsd` and `domU-linux` at boot and shut them
 shutdown, in rc.conf add:  down cleanly on dom0 shutdown, add the following in rc.conf:
   
         xendomains="foo bar"  [[!template id=filecontent name="/etc/rc.conf" text="""
   xendomains="domU-netbsd domU-linux"
 Note that earlier versions of the xentools41 xendomains rc.d script  """]]
 used xl, when one should use xm with 4.1.  
   
 Creating specific unprivileged domains (domU)  #Creating a domU
 =============================================  
   
 Creating domUs is almost entirely independent of operating system.  We  Creating domUs is almost entirely independent of operating system.  We
 have already presented the basics of config files.  Note that you must  have already presented the basics of config files.  Note that you must
 have already completed the dom0 setup so that "xl list" (or "xm list")  have already completed the dom0 setup so that "xl list" works.
 works.  
   
 Creating an unprivileged NetBSD domain (domU)  Creating a NetBSD domU
 ---------------------------------------------  ----------------------
   
 See the earlier config file, and adjust memory.  Decide on how much  See the earlier config file, and adjust memory.  Decide on how much
 storage you will provide, and prepare it (file or lvm).  storage you will provide, and prepare it (file or LVM).
   
 While the kernel will be obtained from the dom0 file system, the same  While the kernel will be obtained from the dom0 file system, the same
 file should be present in the domU as /netbsd so that tools like  file should be present in the domU as /netbsd so that tools like
Line 535  kernel to / and change the kernel line i Line 464  kernel to / and change the kernel line i
   
         kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"          kernel = "/home/bouyer/netbsd-INSTALL_XEN3_DOMU"
   
 Then, start the domain as "xl create -c configname".  Then, start the domain as "xl create -c configfile".
   
 Alternatively, if you want to install NetBSD/Xen with a CDROM image, the following  Alternatively, if you want to install NetBSD/Xen with a CDROM image, the following
 line should be used in the config file.  line should be used in the config file.
Line 580  not really a Xen-specific issue, but bec Line 509  not really a Xen-specific issue, but bec
 obtained from the dom0, it is far more likely to be out of sync or  obtained from the dom0, it is far more likely to be out of sync or
 missing with Xen.)  missing with Xen.)
   
 Creating an unprivileged Linux domain (domU)  Creating a Linux domU
 --------------------------------------------  ---------------------
   
 Creating unprivileged Linux domains isn't much different from  Creating unprivileged Linux domains isn't much different from
 unprivileged NetBSD domains, but there are some details to know.  unprivileged NetBSD domains, but there are some details to know.
Line 624  To get the Linux console right, you need Line 553  To get the Linux console right, you need
 to your configuration since not all Linux distributions auto-attach a  to your configuration since not all Linux distributions auto-attach a
 tty to the xen console.  tty to the xen console.
   
 Creating an unprivileged Solaris domain (domU)  Creating a Solaris domU
 ----------------------------------------------  -----------------------
   
 See possibly outdated  See possibly outdated
 [Solaris domU instructions](/ports/xen/howto-solaris/).  [Solaris domU instructions](/ports/xen/howto-solaris/).
Line 701  note that only the "xpci" lines are unus Line 630  note that only the "xpci" lines are unus
         cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives          cd*     at scsibus? target ? lun ?      # SCSI CD-ROM drives
   
   
 NetBSD as a domU in a VPS  #NetBSD as a domU in a VPS
 =========================  
   
 The bulk of the HOWTO is about using NetBSD as a dom0 on your own  The bulk of the HOWTO is about using NetBSD as a dom0 on your own
 hardware.  This section explains how to deal with Xen in a domU as a  hardware.  This section explains how to deal with Xen in a domU as a
Line 767  Amazon Line 695  Amazon
 ------  ------
   
 See the [Amazon EC2 page](/amazon_ec2/).  See the [Amazon EC2 page](/amazon_ec2/).
   
 Random pointers  
 ===============  
   
 This section contains links from elsewhere not yet integrated into the  
 HOWTO, and other guides.  
   
 * http://www.lumbercartel.ca/library/xen/  
 * http://pbraun.nethence.com/doc/sysutils/xen_netbsd_dom0.html  
 * https://gmplib.org/~tege/xen.html  

Removed from v.1.157  
changed lines
  Added in v.1.167


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