Difference between revisions of "Xen on CentOS - Automating Installation-Administration"
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!!! IMPORTANT: !!! | !!! IMPORTANT: !!! | ||
| − | * foresee a logvol /var/lib/xen/save which will take "Speicherabbilder" of running | + | * foresee a logvol with mount point /var/lib/xen/save which will take "Speicherabbilder" of running |
domUs, when the dom0 gets the reboot command, therefore it should be | domUs, when the dom0 gets the reboot command, therefore it should be | ||
| − | as large as available RAM + something (summ of all swap of domUs, see below) | + | as large as available RAM + something (summ of all swap of domUs ?, see below) |
| − | * give each domU not more than 512MB swap, if a domU | + | * give each domU not more than 512MB swap, if a domU excessively uses swap it will anyways got stuck. |
== Naming convention: == | == Naming convention: == | ||
| Line 24: | Line 24: | ||
= Virtualization considerations = | = Virtualization considerations = | ||
| − | * Dom0 (Host) needs < 10G for its system, tmp is not extensively used nor is var. To prevent the system to be unresponsive due to full / fs we could give 4GB /tmp and /var each. These values can be smaller if we have hardware which has some disk space restrictions. | + | |
| + | == dom0 Filesystem layout == | ||
| + | * Dom0 (Host) needs < 10G for its system, tmp is not extensively used nor is var. To prevent the system to be unresponsive due to full / fs we could give 4GB /tmp and /var each and an extra volume for /var/lib/xen/save (size .gt. pys. RAM in dom0) to take the files in which the state of the domUs are saved (roughly comparable to hybernate a running computer). These values can be smaller if we have hardware which has some disk space restrictions. | ||
| + | |||
* For performance its best to limit the Memory of the dom0 to 512 MB and to prevent it from ballooning (i.e. takes all available memory) | * For performance its best to limit the Memory of the dom0 to 512 MB and to prevent it from ballooning (i.e. takes all available memory) | ||
| Line 30: | Line 33: | ||
* Dom0-swap should never happen, there are no processes that consume memory, if it swaps something went wrong, just in case we can try 1 GB swap | * Dom0-swap should never happen, there are no processes that consume memory, if it swaps something went wrong, just in case we can try 1 GB swap | ||
| − | == PE-1950 configuration == | + | === PE-1950 configuration === |
Hard disks: 2 X 500GB | Hard disks: 2 X 500GB | ||
principle layout: | principle layout: | ||
| Line 41: | Line 44: | ||
* LVM | * LVM | ||
Volumegroup System, Size: rest of available space | Volumegroup System, Size: rest of available space | ||
| − | I System-Volumes-Dom0 [/, /tmp] fs: ext3 | + | I System-Volumes-Dom0 [/, /tmp, /var /var/lib/xen/save] fs: ext3 |
II DomU-lvms added when needed | II DomU-lvms added when needed | ||
| − | == PE-2950 configuration == | + | === PE-2950 configuration === |
Hard disks: 4 X 500GB | Hard disks: 4 X 500GB | ||
principle layout:hardware raid-10 | principle layout:hardware raid-10 | ||
| Line 54: | Line 57: | ||
* LVM | * LVM | ||
| − | + | Volumegroups systemvg and xenvg, Size: rest of available space | |
| − | + | * System-Volumes-Dom0 [/, /tmp, /var, /var/lib/xen/save] fs: ext3 | |
| − | + | * DomU-lvms added when needed | |
| + | |||
| + | == Network == | ||
| + | === DomU MAC Adresses === | ||
| + | Xen domUs have the MAC-Addresses in 00:16:3e:*:*:*. | ||
| + | To avoid collisions in MAC adresses one can take the IP of the domU A.B.C.D and use the hex values for B,C and D. The following command might be usefull: | ||
| + | printf "00:16:3e:%02x:%02x:%02x\n" {B,C,D} | ||
| + | replace B,C,D accordingly. | ||
Latest revision as of 10:38, 23 March 2009
UNDER CONSTRUCTION
Introduction
This document assumes an functioning quattor environment and an installationserver with dhcp, tftp, and pxeboot.
Needed Tools
- Quattor [Quattor at nikhef]
- pypxeboot (on dom0s)
filesystem dom0
Quattor templates: /cfg/sites/ndpf/site/filesystems/*.tpl
!!! IMPORTANT: !!! * foresee a logvol with mount point /var/lib/xen/save which will take "Speicherabbilder" of running domUs, when the dom0 gets the reboot command, therefore it should be as large as available RAM + something (summ of all swap of domUs ?, see below) * give each domU not more than 512MB swap, if a domU excessively uses swap it will anyways got stuck.
Naming convention:
since the Filesystem layout depends on the hardware [how many hard disks 2-4, which raid (1 or 1-0)] and on the function in terms of xen-Dom0, xen-DomU, generic, ... I used the following scheme <hardware>-<function>.tpl The filesystem Template for our Dell-Power-Edge-1950 -function xen-Dom0 would then be: pe1950-x0.tpl
Virtualization considerations
dom0 Filesystem layout
- Dom0 (Host) needs < 10G for its system, tmp is not extensively used nor is var. To prevent the system to be unresponsive due to full / fs we could give 4GB /tmp and /var each and an extra volume for /var/lib/xen/save (size .gt. pys. RAM in dom0) to take the files in which the state of the domUs are saved (roughly comparable to hybernate a running computer). These values can be smaller if we have hardware which has some disk space restrictions.
- For performance its best to limit the Memory of the dom0 to 512 MB and to prevent it from ballooning (i.e. takes all available memory)
- Dom0-swap should never happen, there are no processes that consume memory, if it swaps something went wrong, just in case we can try 1 GB swap
PE-1950 configuration
Hard disks: 2 X 500GB principle layout:
- Raid-1
- Primary Partitions
/boot 512MB /swap 4096MB
- LVM
Volumegroup System, Size: rest of available space I System-Volumes-Dom0 [/, /tmp, /var /var/lib/xen/save] fs: ext3 II DomU-lvms added when needed
PE-2950 configuration
Hard disks: 4 X 500GB principle layout:hardware raid-10
- Primary Partitions
/boot 512MB /swap 4096MB
- LVM
Volumegroups systemvg and xenvg, Size: rest of available space
- System-Volumes-Dom0 [/, /tmp, /var, /var/lib/xen/save] fs: ext3
- DomU-lvms added when needed
Network
DomU MAC Adresses
Xen domUs have the MAC-Addresses in 00:16:3e:*:*:*. To avoid collisions in MAC adresses one can take the IP of the domU A.B.C.D and use the hex values for B,C and D. The following command might be usefull:
printf "00:16:3e:%02x:%02x:%02x\n" {B,C,D}
replace B,C,D accordingly.
