CentOS virt - Jan 2021 - OS-level virtualization using LXC and systemd-nspawn containers

Greetings,

----- Original Message -----
> 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.
> LXC/LXD is the same technology, as I understand from
> linuxcontainers.org
linuxcontainers.org is owned by Canonical and yes it documents LXC... but 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.
> 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".
 
TYL,
-- 
Scott Dowdle
704 Church Street
Belgrade, MT 59714
(406)388-0827 [home]
(406)994-3931 [work]

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:

http://ftp.netinch.com/pub/openvz/virtuozzo/releases/

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,
  Gena