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Physical to container

2,758 bytes added, 06:03, 26 October 2017
→‎Prepare a new “empty” container
A rough description of how to migrate existing physical server into a [[container]].
Ll10xC <== Preparing to migrate == Stop most services on a machine to be migrated. “Most” means services such as web server, databases and the like — so you will not lose your data. Just leave the bare minimum (including ssh daemon). To make things easier you may like to first follow the basic instructions elsewhere and create a href="http://vcdhcndzvrkedummy container based on the same Linux distribution you want to migrate.com/">vcdhcndzvrke</That way you can take that dummy as a>, [url=http://wlzccnbajovktemplate and then copy to your new migrated container and modify. You can later discard this dummy. {{Note|Still better is to use this container from the same Linux distribution you want to migrate as the starting point for the new installation.com/]wlzccnbajovk[/url]In this case, [link=http://evdvbvxnaocr.com/]evdvbvxnaocr[/link]if we are carefull to copy only the needed files from the original system, http://sqehjqssrncmwe will be able to skip many of the following steps.com/}}
== Prepare a new “empty” container ==
For OpenVZ this would mean the following (assume you chose CT ID of 123):
<source lang="bash">
mkdir /vz/root/123 /vz/private/123
cat /etc/vz/conf/ve-vps.basic.conf-sample > /etc/vz/conf/123.conf</source>
Hint: {{Note|Now comes the dummy container handy mentioned above: Simply copy the xxx.conf file of the dummy to your new yyy.conf and modify it.}}
{{Note|If you have created a container from the same distro as the basis for the migration, simply take note of the CT ID and skip this step.}}
== Copying the data ==
=== rsync ===
rsync example (run from On the new HN)create a file <code>/tmp/exclude.txt</code> with: rsync -arvpz --numeric-ids --exclude=<pre>/tmp/boot/lib/modules/etc/blkid/etc/dev --exclude=mtab/proc --exclude=etc/tmp -e ssh root@a.b.c.d:lvm/ etc/vzfstab/privateetc/123udev</pre>
(Commentand run <b>rsync</b> as follows: I think <source lang="bash"> rsync -avz -H -X --one -file-system --numeric-ids --exclude-from=/tmp/exclude.txt -e ssh root@a.b.c.d:/ /vz/private/123/</source> {{Note|You should add the "<code>-H" </code> option, so hardlinks will be preserved during sync. and also include the <code>-X</code> option to preserve file extended attributes}} If your source system have multiple partitions (for example <code>/var</code> or <code>/home</code>) repeat the command above for each partition in your system; for example:<source lang="bash">rsync -avz -H -X --one-file-system --numeric-ids -[[Special:Contributions/194.95.66e ssh root@a.21|194b.95c.66.21]] 12d:05, 8 September 2011 (UTC))/var/ /vz/private/123/var/</source>
'''Advantage:''' Your system doesn't really go down.
You have to add <code>OSTEMPLATE=xxx</code> line to <code>/etc/vz/conf/123.conf</code> file, where <code>xxx</code> would be distribution name (like <code>debian-3.0</code>) for vzctl to be able to make changes specific for this distribution.
{{Note|If you copied from the dummy container or are using it as basis for your migrated system then this step is already accomplished.}}
=== IP address(es) ===
=== /etc/fstab ===
Since you do not have any real disk partitions in a container, /etc/fstab (or most part of it) is no longer needed. Empty it (excluding the lines for <code>/dev/pts</code>, <code>/proc</code>, <code>/sys</code> and such):
<source lang="bash">
mv /vz/private/123/etc/fstab /vz/private/123/etc/fstab.old
egrep '/dev/pts|/dev/shm|/proc|/sys' /vz/private/123/etc/fstab.old > /vz/private/123/etc/fstab
</source>
You can also mount a devpts in a running (but not fully functional) container:
vzctl exec 123 mount -t devpts none /dev/pts
 
A still better approach would be simply to copy the <code>/etc/fstab</code> from a previously created container from a template of the same or similar distribution. In the case of RedHat/CentOS 5 this is:
<source lang="bash">
none /dev/pts devpts rw 0 0
</source>
and for RedHat/CentOS 6:
<source lang="bash">
none /dev/pts devpts rw,gid=5,mode=620 0 0
</source>
=== /dev ===
{{Note| Once again if you are using the container from the same distro as basis, and you were carefull to not overwrite <code>/dev</code> with <b>rsync</b> by using the <code>--one-file-system</code> option, you can skip this section}}
==== Introduction: static /dev ====
Please pay attention to the access permissions of the device files being created: a default file mode for newly created files is affected by <code>umask</code> ([[w:umask]]). You can use --mode option for <code>mknod</code> to set the desired permissions.
Hint:{{Note|Now comes the dummy container handy mentioned above: Simply copy the entire /dev directory of the dummy to your new migrated container - worked in my case at least with Debian Etch.}}
==== tty device nodes ====
===/proc===
{{Note| One more time you may skip this if you are using a container created from a template of the same distro as your basis system.}}
 
Make sure the /proc directory exists:
ls -la /vz/private/123/ | grep proc
=== /etc/init.d services ===
Some system services can (or in some cases should) be disabledand/or uninstaled. A few good candidates are:
* acpid, amd (not needed)
* lm_sensors (container does not have access to hardware sensors)
* microcodectl (container can not update CPU microcode)
* netplugd (container does not have real Ethernet device)* irqbalance (this is handled in host node)* auditd ( not needed in container)* lvm2-monitor (no LVM in containers)* ntp/ntpd (clock taken from host node)
To see which services are enabled:
iface lo inet loopback
iface eth0 inet dhcpstatic
address 10.0.0.4
netmask 255.0.0.0
* Centos 5.7 with MySQL, Apache, Nginx, Memcached, Postfix, Openx, etc. --[[User:juranas|Juranas]] 18 November 2011
* RedHat Enterprise Linux 5 (rhel 5.6 - x86_64) 14:50, 18 November 2011
* Debian 6.0.4 with DTC Hosting Contro Panel . 15:00, 14 May 2012
* Debian 6, LAMP with ISPManager CP (no adjustments were made, just transferred the file structure and created ctid.conf) 03:19, 15 Jun 2012
* Debian 5.0.3, with Mysql, Apache, ISCP omega, Postfix, etc --[[Special:Contributions/91.143.222.253|91.143.222.253]] 19:47, 28 June 2012 (EDT)
* Debian 6.0.5 with artica-zarafa, 20 Nov 2012
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