The --monitor-host option was added to the 'init-container' command in
commit 8b84b5e460 to accommodate Podman versions older than 1.2.0
that didn't have the '--dns none' and '--no-hosts' options for
'podman create'. These options are necessary to keep the Toolbx
container's /etc/resolv.conf and /etc/hosts files synchronized with
those of the host.
Note that Podman 1.2.0 was already available a few months before
commit 8b84b5e460 introduced the --monitor-host option. The
chances of someone using an older Podman back then was already on the
decline, and it's very unlikely that a container created with such a
Podman has survived till this date.
Commit b6b484fa79 raised the minimum required Podman version to
1.4.0, and made the '--dns none' and '--no-hosts' options a hard
requirement. The minimum required Podman version was again raised
recently in commit 8e80dd5db1 to 1.6.4. Therefore, these days,
there's no need to separately use the --monitor-host option of
'init-container' for newly created containers to indicate that the
Podman version wasn't older than 1.2.0.
Given all this, it's time to stop using the --monitor-host option of
'init-container', and assume that it's always set. The option is still
accepted to retain compatibility with existing Toolbx containers.
For containers that were created with the --monitor-host option, a
deprecation notice will be shown as:
$ podman start --attach CONTAINER
Flag --monitor-host has been deprecated, it does nothing
...
https://github.com/containers/toolbox/pull/617
58638c5940