telco-ran: Pre-create /run/netns bindmount so it propagates to the container-mount-namespace

This closes a race between running `ip netns add` inside the
container-mount-namespace namespace and running it outside of the
container-mount-namespace namespace.

The cause of the race is that the /run/netns/ bindmount created by `ip
netns add` is created with rshared properties, so the external call
would shadow the internal call any time the internal call occurs first.
Forcing the call to happen on the outside ensures any subsequent
internal calls will simply reuse the existing bindmount (as intended).

Signed-off-by: Jim Ramsay <jramsay@redhat.com>

Author: lack

telco-ran/configuration/extra-manifests-builder/01-container-mount-ns-and-kubelet-conf/container-mount-namespace.service

@@ -11,3 +11,14 @@ ExecStartPre=bash -c "findmnt ${RUNTIME_DIRECTORY} || mount --make-unbindable --
 ExecStartPre=touch ${BIND_POINT}
 ExecStart=unshare --mount=${BIND_POINT} --propagation slave mount --make-rshared /
 ExecStop=umount -R ${RUNTIME_DIRECTORY}
+
+# Initialize /run/netns as a shared mount point to prevent shadowing race condition
+# This must happen before CRI-O starts to ensure all namespace bind mounts have
+# the correct parent mount. Without this, 'ip netns add' (called later by network
+# components) would create the mount point and shadow any earlier namespace mounts
+# created by CRI-O's pinns, causing pods to fail with 'setns: Invalid argument'.
+# Creating and deleting a netns retains the side-effect of creating the
+# /run/netns mountpoint (but base exit code solely on whether the mountpoint is
+# present)
+# Reference: OCPBUGS-83562
+ExecStartPost=bash -c "ip netns add kubensmnt && ip netns delete kubensmnt || mountpoint -q /run/netns"

telco-ran/configuration/kube-compare-reference/machine-config/kubelet-configuration-and-container-mount-hiding/01-container-mount-ns-and-kubelet-conf-master.yaml

@@ -36,6 +36,17 @@ spec:
           ExecStartPre=touch ${BIND_POINT}
           ExecStart=unshare --mount=${BIND_POINT} --propagation slave mount --make-rshared /
           ExecStop=umount -R ${RUNTIME_DIRECTORY}
+
+          # Initialize /run/netns as a shared mount point to prevent shadowing race condition
+          # This must happen before CRI-O starts to ensure all namespace bind mounts have
+          # the correct parent mount. Without this, 'ip netns add' (called later by network
+          # components) would create the mount point and shadow any earlier namespace mounts
+          # created by CRI-O's pinns, causing pods to fail with 'setns: Invalid argument'.
+          # Creating and deleting a netns retains the side-effect of creating the
+          # /run/netns mountpoint (but base exit code solely on whether the mountpoint is
+          # present)
+          # Reference: OCPBUGS-83562
+          ExecStartPost=bash -c "ip netns add kubensmnt && ip netns delete kubensmnt || mountpoint -q /run/netns"
         name: container-mount-namespace.service
       - dropins:
         - contents: |

telco-ran/configuration/kube-compare-reference/machine-config/kubelet-configuration-and-container-mount-hiding/01-container-mount-ns-and-kubelet-conf-worker.yaml

@@ -36,6 +36,17 @@ spec:
           ExecStartPre=touch ${BIND_POINT}
           ExecStart=unshare --mount=${BIND_POINT} --propagation slave mount --make-rshared /
           ExecStop=umount -R ${RUNTIME_DIRECTORY}
+
+          # Initialize /run/netns as a shared mount point to prevent shadowing race condition
+          # This must happen before CRI-O starts to ensure all namespace bind mounts have
+          # the correct parent mount. Without this, 'ip netns add' (called later by network
+          # components) would create the mount point and shadow any earlier namespace mounts
+          # created by CRI-O's pinns, causing pods to fail with 'setns: Invalid argument'.
+          # Creating and deleting a netns retains the side-effect of creating the
+          # /run/netns mountpoint (but base exit code solely on whether the mountpoint is
+          # present)
+          # Reference: OCPBUGS-83562
+          ExecStartPost=bash -c "ip netns add kubensmnt && ip netns delete kubensmnt || mountpoint -q /run/netns"
         name: container-mount-namespace.service
       - dropins:
         - contents: |

telco-ran/configuration/source-crs/extra-manifest/01-container-mount-ns-and-kubelet-conf-master.yaml

@@ -36,6 +36,17 @@ spec:
           ExecStartPre=touch ${BIND_POINT}
           ExecStart=unshare --mount=${BIND_POINT} --propagation slave mount --make-rshared /
           ExecStop=umount -R ${RUNTIME_DIRECTORY}
+
+          # Initialize /run/netns as a shared mount point to prevent shadowing race condition
+          # This must happen before CRI-O starts to ensure all namespace bind mounts have
+          # the correct parent mount. Without this, 'ip netns add' (called later by network
+          # components) would create the mount point and shadow any earlier namespace mounts
+          # created by CRI-O's pinns, causing pods to fail with 'setns: Invalid argument'.
+          # Creating and deleting a netns retains the side-effect of creating the
+          # /run/netns mountpoint (but base exit code solely on whether the mountpoint is
+          # present)
+          # Reference: OCPBUGS-83562
+          ExecStartPost=bash -c "ip netns add kubensmnt && ip netns delete kubensmnt || mountpoint -q /run/netns"
         name: container-mount-namespace.service
       - dropins:
         - contents: |

telco-ran/configuration/source-crs/extra-manifest/01-container-mount-ns-and-kubelet-conf-worker.yaml

@@ -36,6 +36,17 @@ spec:
           ExecStartPre=touch ${BIND_POINT}
           ExecStart=unshare --mount=${BIND_POINT} --propagation slave mount --make-rshared /
           ExecStop=umount -R ${RUNTIME_DIRECTORY}
+
+          # Initialize /run/netns as a shared mount point to prevent shadowing race condition
+          # This must happen before CRI-O starts to ensure all namespace bind mounts have
+          # the correct parent mount. Without this, 'ip netns add' (called later by network
+          # components) would create the mount point and shadow any earlier namespace mounts
+          # created by CRI-O's pinns, causing pods to fail with 'setns: Invalid argument'.
+          # Creating and deleting a netns retains the side-effect of creating the
+          # /run/netns mountpoint (but base exit code solely on whether the mountpoint is
+          # present)
+          # Reference: OCPBUGS-83562
+          ExecStartPost=bash -c "ip netns add kubensmnt && ip netns delete kubensmnt || mountpoint -q /run/netns"
         name: container-mount-namespace.service
       - dropins:
         - contents: |