cgroups: v2: always init parent dirs

By skipping parents we were hitting an issue with the way k8s cgroups
are managed since it is creating those cgroups.
This change ensures we apply subtree_control to all parents as needed.

Before this change pods would fail to start due to missing `cpu.weight`
since we were not delegating cgroup control.

Signed-off-by: Brian Goff <[email protected]>

Makefile

@@ -43,10 +43,9 @@ test/k8s/_out/img: test/k8s/Dockerfile Cargo.toml Cargo.lock $(shell find . -typ
 	mkdir -p $(@D) && $(DOCKER_BUILD) -f test/k8s/Dockerfile --iidfile=$(@) --load  .
 
 .PHONY: test/k8s/cluster
-test/k8s/cluster: target/wasm32-wasi/$(TARGET)/img.tar bin/kind test/k8s/_out/img
-	kind create cluster --name $(KIND_CLUSTER_NAME) --image="$(shell cat test/k8s/_out/img)" && \
-	# Load the image into the cluster. We can't use `kind load image-archive` because it doesn't support non-native arch images. \
-	docker exec -i $(KIND_CLUSTER_NAME)-control-plane ctr -n k8s.io image import --all-platforms - < $(<)
+test/k8s/cluster: target/wasm32-wasi/$(TARGET)/img.tar bin/kind test/k8s/_out/img bin/kind
+	bin/kind create cluster --name $(KIND_CLUSTER_NAME) --image="$(shell cat test/k8s/_out/img)" && \
+	bin/kind load image-archive --name $(KIND_CLUSTER_NAME) $(<)
 
 .PHONY: test/k8s/deploy
 test/k8s/deploy: test/k8s/cluster

crates/containerd-shim-wasm/src/sandbox/cgroups/cgroupv2.rs

@@ -38,12 +38,6 @@ impl CgroupV2 {
         for d in p.iter() {
             full = safe_join(full.clone(), PathBuf::from(d))?;
 
-            if full.exists() {
-                debug!("skipping creation of existing cgroup: {}", full.display());
-                // This is a pre-existing cgroup, so we won't touch subtree control.
-                continue;
-            }
-
             if full.to_str() == self.full_path()?.to_str() {
                 // This is the last element in the path, so we don't need to create it.
                 // The cgroup will get created later when we try to write to a file in it.