[CentOS-virt] OS-level virtualization using LXC and systemd-nspawn containers

Tue Jan 26 16:12:38 UTC 2021
Gena Makhomed <gmm at csdoc.com>

On 26.01.2021 0:05, Scott Dowdle wrote:

>> OpenVZ 7 has no updates, and therefore is not suitable for production.

> The free updates lag behind the paid Virtuozzo 7 version and plenty of people are using it in production. I'm not one of those.

See all released OpenVZ 7 updates:


Lag between two serial updates can be up to 4-5 month.

OpenVZ 7 has many other disadvantages, so I can't use it for production.

>> LXC/LXD is the same technology, as I understand from linuxcontainers.org

> LXD is a management layer on top of it which provides for easy clustering and even managing VMs.  I think it is the closest thing to vzctl/prlctl from OpenVZ.

"Yes, you could use LXC without LXD. But you probably would not want to.
On its own, LXC will give you only a basic subset of features.
For a production environment, you’ll want to use LXD".

>> podman can't be a replacement for OpenVZ 6 / systemd-nspawn because
>> it destroys the root filesystem on the container stop, and all
>> changes made in container configs and other container files will be lost.
>> This is a nightmare for the website hosting server with containers.

> No, it does NOT destroy the delta disk (that's what I call where changes are stored) upon container stop and I'm not sure why you think it does.  You can even export a systemd unit file to manage the container as a systemd service or user service.  volumes are a nice way to handle persistence of data if you want to nuke the existing container and make a new one from scratch without losing your data.  While it is true you have to approach the container a little differently, podman systemd containers are fairly reasonable "system containers".

podman is replacement for Docker,
it is not replacement for OpenVZ 6 containers.

I have containers with 1.6 TiB of valuable data - podman
not designed to work in this mode and in such conditions.

So I have only two alternatives for OS-level virtualization:
LXC or systemd-nspawn.

Best regards,