pre-install: Use ctr from the host

Let's take the same approach taken to use systemd and use ctr directly
from the host, which helps us to avoid actually mounting /run/ content
into our daemonset.

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>

install/pre-install-payload/Dockerfile

@@ -116,6 +116,3 @@ COPY ${NYDUS_SNAPSHOTTER_ARTIFACTS} ${NODE_DESTINATION}/share/nydus-snapshotter/
 
 ARG CONTAINER_ENGINE_ARTIFACTS=./scripts
 COPY ${CONTAINER_ENGINE_ARTIFACTS}/* ${DESTINATION}/scripts/
-
-# Also copy `ctr` to our final image, so we can use it to remove nydus snapshots
-COPY --from=official-containerd-binary-downloader ${NODE_DESTINATION}/bin/ctr /usr/bin/ctr

install/pre-install-payload/scripts/reqs-deploy.sh

@@ -13,6 +13,10 @@ die() {
 	exit 1
 }
 
+function host_ctr() {
+	nsenter --target 1 --mount ctr "${@}"
+}
+
 function host_systemctl() {
 	nsenter --target 1 --mount systemctl "${@}"
 }
@@ -112,8 +116,8 @@ function uninstall_containerd_artefacts() {
 
 function uninstall_nydus_snapshotter_artefacts() {
 	if host_systemctl list-units | grep -q nydus-snapshotter; then
-		for i in `ctr -n k8s.io snapshot --snapshotter nydus list | grep -v KEY | cut -d' ' -f1`; do
-			ctr -n k8s.io snapshot --snapshotter nydus rm $i || true
+		for i in `host_ctr -n k8s.io snapshot --snapshotter nydus list | grep -v KEY | cut -d' ' -f1`; do
+			host_ctr -n k8s.io snapshot --snapshotter nydus rm $i || true
 		done
 
 		remove_nydus_snapshotter_from_containerd