Wondering how to migrate Openvz to lxc proxmox? We can help you.

As part of our Server Management Services, we assist our customers with several similar queries.

Today, let us see procedure followed by our Support Techs in order to perform this task.

How to migrate Openvz to lxc proxmox?

OpenVZ is not available for Kernels above 2.6.32, therefore a migration is necessary.

Today, let us see the steps followed by our Support Techs to perform this task.

Basically you have to follow these steps:

On the Proxmox VE 3.x node:

1. Firstly, note the network settings used by the container
2. Then, make a backup of the OpenVZ container

On the Proxmox VE 4.x node:

1. Restore/create a LXC container based on the backup
2. Then, configure the network with the previous settings
3. Boot and voilà, it works

Unsupported OpenVZ templates

All OpenVZ templates are not supported.

If you try to convert OpenVZ template with unsupported OS then you will get error message during pct restore command and restore will fail.

unsupported fedora release ‘Fedora release 14 (Laughlin)’

Step by step conversion

Firstly, login with ssh on your Proxmox VE 3.x node:

Suppose you want to migrate three different containers: a CentOS container, an Ubuntu, and a Debian container.

vzlist
CTID NPROC STATUS IP_ADDR HOSTNAME
100 20 running - centos6vz.proxmox.com
101 18 running - debian7vz.proxmox.com
102 20 running 192.168.15.142 ubuntu12vz.proxmox.com

Get the network configuration of the OpenVZ containers, and note it somewhere

A) If your container uses a venet device, you get the address directly from the command line:

vzlist 102
CTID NPROC STATUS IP_ADDR HOSTNAME
102 20 running 192.168.15.142 ubuntu12vz.proxmox.com

B) If your container uses veth, the network configuration is done inside the container.

How to find the network configuration depends on which OS is running inside the container:

If you have a CentOS based container, you can get the network configuration like this:

# start a root shell inside the container 100
vzctl enter 100
cat /etc/sysconfig/network-scripts/ifcfg-eth0
exit

There may be more than one network interface in CentOS that will be seen using ifcfg-eth1 and the like in the above command.

If you have a Debian, Ubuntu or Turnkey Linux appliance (all network interfaces are available in one go here):

vzctl enter 101
cat /etc/network/interfaces
exit

Make a backup of your containers

Firstly, choose on which storage you want to backup the containers.

# List available storages:
pvesm status
freenas nfs 1 27676672 128 27676544 0.50%
local dir 1 8512928 2122088 6390840 25.43%
nas-iso nfs 1 2558314496 421186560 2137127936 16.96%

By default, this storage does not allow backups to be stored, so make sure you enable it for backup contents. (See Storage type Content)

Then backup all the containers

# Stop the container, and start a backup right after the shutdown:
vzctl stop 100 && vzdump 100 -storage local
vzctl stop 101 && vzdump 101 -storage local
vzctl stop 102 && vzdump 102 -storage local

At that point you can either:

A) Upgrade your Proxmox VE 3.x node to Proxmox VE 4.x
B) Copy the backups to a Proxmox VE 4.x node, and do the conversion on the Proxmox VE 4.x node

Suppose you follow option B) (copy the backups to the Proxmox VE 4.x node, and convert to LXC format)

# Copy each container tar backup to the pve4 node via ssh:
cd /var/lib/vz/dump/
scp vzdump-openvz-100-2015_08_27-10_46_47.tar root@pve4:/var/lib/vz/dump
scp vzdump-openvz-101-2015_08_27-10_50_44.tar root@pve4:/var/lib/vz/dump
scp vzdump-openvz-102-2015_08_27-10_56_34.tar root@pve4:/var/lib/vz/dump

Restore/Create LXCs based on your backup

Now switch to the Proxmox VE 4 node, and create containers based on the backup:

pct restore 100 /var/lib/vz/dump/vzdump-openvz-100-2015_08_27-10_46_47.tar
pct restore 101 /var/lib/vz/dump/vzdump-openvz-101-2015_08_27-10_50_44.tar
pct restore 102 /var/lib/vz/dump/vzdump-openvz-102-2015_08_27-10_56_34.tar

At that point you should be able to see your containers in the web interface, but they still have no network.

Please note if you want to / have to restore to a different storage than the default ‘local’ one, add “-storage STORAGEID” to the “pct restore” command.

E.g., if you have a ZFS storage called ‘local-zfs’, you can use the following command to restore:

pct restore 100 /var/lib/vz/dump/vzdump-openvz-100-2015_08_27-10_46_47.tar -storage local-zfs

Add network configuration based on the original settings

LXCs uses virtual network adapter which are bridged to the physical interface of your host.

In Proxmox VE 3.x the configuration of each container using a veth device had to be done inside the container.

In Proxmox VE 4.x you can do this directly from the host.

Add network configuration via the GUI

For each container:

1. Firstly, select the container by clicking on it
2. Then, go to the Network tab
3. Next, click Add device
4. On the veth device panel, add a device with the parameters:

ID: net0
name eth0
put your IP address and the corresponding netmask in the following format 192.168.5.75/24

Add network configuration via the CLI

pct set 101 -net0 name=eth0,bridge=vmbr0,ip=192.168.15.144/24,gw=192.168.15.1
pct set 102 -net0 name=eth0,bridge=vmbr0,ip=192.168.15.145/24,gw=192.168.15.1

Start the containers

pct start 100
pct start 101
pct start 102

and voilà, you can now log in to a container and check that your services are running

pct enter 100

[Need help with similar query? We’d be glad to assist you]

Conclusion

In short, today we saw how our Support Techs migrate Openvz to lxc proxmox.