The metadata store is in the best place to handle events directly after
the database has been updated. This prevents every user of the image
store interface from having to know whether or not they are responsible
for publishing events and avoid double events if the grpc local service
is used.
Signed-off-by: Derek McGowan <derek@mcg.dev>
Prior to this commit, `readOnly` volumes were not recursively read-only and
could result in compromise of data;
e.g., even if `/mnt` was mounted as read-only, its submounts such as
`/mnt/usbstorage` were not read-only.
This commit utilizes runc's "rro" bind mount option to make read-only bind
mounts literally read-only. The "rro" bind mount options is implemented by
calling `mount_setattr(2)` with `MOUNT_ATTR_RDONLY` and `AT_RECURSIVE`.
The "rro" bind mount options requires kernel >= 5.12, with runc >= 1.1 or
a compatible runtime such as crun >= 1.4.
When the "rro" bind mount options is not available, containerd falls back
to the legacy non-recursive read-only mounts by default.
The behavior is configurable via `/etc/containerd/config.toml`:
```toml
version = 2
[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.runc]
# treat_ro_mounts_as_rro ("Enabled"|"IfPossible"|"Disabled")
# treats read-only mounts as recursive read-only mounts.
# An empty string means "IfPossible".
# "Enabled" requires Linux kernel v5.12 or later.
# This configuration does not apply to non-volume mounts such as "/sys/fs/cgroup".
treat_ro_mounts_as_rro = ""
```
Replaces:
- kubernetes/enhancements issue 3857
- kubernetes/enhancements PR 3858
Note: this change does not affect non-CRI clients such as ctr, nerdctl, and Docker/Moby.
RRO mounts have been supported since nerdctl v0.14 (containerd/nerdctl PR 511)
and Docker v25 (moby/moby PR 45278).
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
This change simplifies the CRI plugin dependencies by not requiring the
CRI image plugin to depend on any other CRI components. Since other CRI
plugins depend on the image plugin, this allows prevents a dependency
cycle for CRI configurations on a base plugin.
Signed-off-by: Derek McGowan <derek@mcg.dev>
