[release/1.7] Allow proxy plugins to have capabilities

[henry118]

Backport: allow proxy plugins to have capabilities

Original PR: #10337

Fixes: #10732

Signed-off-by: Henry Wang [email protected]
(cherry picked from commit 5b8dfbd)

[henry118]

/test pull-containerd-node-e2e-1-7

[samuelkarp]

We don't generally backport new features. Is there a compelling reason to do so here?

[henry118]

This will allow remote snapshotters (i.e. fuse-overlayfs) to report their capabilities like "id-map", so that the id mapped mount optimal path can be executed to speed up the container startup times in userns use cases.

containerd/snapshotter_opts_unix.go

Line 49 in 6fbbe70

// Snapshotter supports ID remapping, we don't need to do anything.

[henry118]

Since the remap-labels option is already part of 1.7, and fuse-overlayfs is also the only one that claims to support it. I am not sure how it could possibly work without this patch. Therefore this is a bug that should be fixed IMHO.

containerd/cmd/ctr/commands/run/run_unix.go

Lines 176 to 181 in 6fbbe70

	// use snapshotter opts or the remapped snapshot support to shift the filesystem
	// currently the only snapshotter known to support the labels is fuse-overlayfs:
	// https://github.com/AkihiroSuda/containerd-fuse-overlayfs
	if context.Bool("remap-labels") {
	cOpts = append(cOpts, containerd.WithNewSnapshot(id, image,
	containerd.WithRemapperLabels(0, uidMap.HostID, 0, gidMap.HostID, uidMap.Size)))

[henry118]

I reported a bug #10732 for this case.

[henry118]

/test pull-containerd-node-e2e-1-7

[henry118]

@samuelkarp Do you think this patch can be merged?

[henry118]

AFAIK backports like this isn't really unprecedented. For instance, #10096.