Cloning ploop containers

This describes a non-official and unsupported method of cloning ploop containers. It uses shared base ploop delta (this configuration is not officially supported but apparently works just fine).

This method lets you very quickly create thousands of identical containers, saving a lot of disk space as well. This might be useful for example in testing, but should not be used in production.

Legacy OpenVZ

SRCID=50 # "Donor" container ID
TMPL=centos-6-x86_64 # Template to use

vztmpl-dl $TMPL # make sure we use the latest one
vzctl create $SRCID --ostemplate $TMPL

vzctl mount $SRCID
while killall -0 ext4lazyinit; do sleep 1; done
vzctl umount $SRCID

vzctl snapshot $SRCID

for CT in $(seq 1000 2000); do \
       mkdir -p /vz/private/$CT/root.hdd /vz/root/$CT; \
       ln /vz/private/$SRCID/root.hdd/root.hdd /vz/private/$CT/root.hdd/root.hdd; \
       cp -nr /vz/private/$SRCID/root.hdd /vz/private/$CT/; \
       cp /etc/vz/conf/$SRCID.conf /etc/vz/conf/$CT.conf; \
done

vzctl set $SRCID --disabled yes --save # make sure we don't use it

VZ7

The differences from the above script are:

1. Need to run vzpkg instead of vztmpl-dl
2. Need to remove VEID= line from the "donor" config file
3. Need to copy .ve.layout from the donor private area#
4. Base delta name is root.hds not root.hdd

SRCID=50 # "Donor" container ID
TMPL=centos-6-x86_64 # Template to use

vzpkg update cache $TMPL # make sure we use the latest one
vzctl create $SRCID --ostemplate $TMPL
vzctl mount $SRCID
while killall -0 ext4lazyinit; do sleep 1; done
vzctl umount $SRCID

vzctl snapshot $SRCID

sed -ie '/^VEID=/d' /etc/vz/conf/$SRCID.conf

for CT in $(seq 1000 2000); do \
       mkdir -p /vz/private/$CT/root.hdd /vz/root/$CT; \
       ln /vz/private/$SRCID/root.hdd/root.hds /vz/private/$CT/root.hdd/root.hds; \
       cp -nr /vz/private/$SRCID/root.hdd /vz/private/$CT/; \
       cp /etc/vz/conf/$SRCID.conf /etc/vz/conf/$CT.conf; \
       cp -a /vz/private/50/.ve.layout /vz/private/$CT/; \
done

vzctl set $SRCID --disabled yes --save # make sure we don't use it