diff --git a/docker-c8/Dockerfile b/docker-c8/Dockerfile
index ede7c70..2cc43c1 100644
--- a/docker-c8/Dockerfile
+++ b/docker-c8/Dockerfile
@@ -1,5 +1,11 @@
 FROM rockylinux:8
 
+# Add labels
+LABEL org.opencontainers.image.source=https://github.com/stfc/grid-workernode
+LABEL org.opencontainers.image.authors=gstsm@stfc.atlassian.net
+LABEL org.opencontainers.image.description="A specialised container image optimised for high-performance batch job execution in RAL's computing environment. \
+It includes essential software, libraries, and dependencies, ensuring efficient, and scalable job processing, benefiting researchers and organisations."
+
 # Basic dependencies
 RUN dnf -y install \
     zip \
@@ -15,44 +21,49 @@ RUN dnf -y install \
     attr \
     tcsh \
     numactl \
-    bc
-
-# Create all possible pool accounts
-RUN curl -s https://raw.githubusercontent.com/stfc/grid-workernode/master/resources/pool_accounts/create.sh | bash -
+    bc \
+    wget && \
+    # Clean up cache to keep layer size small
+    dnf clean all && \
+    rm -rf /var/cache/dnf
 
 # CVMFS (for SUM tests only; install before adding other repos to ensure we have the latest version)
 RUN dnf -y install https://ecsft.cern.ch/dist/cvmfs/cvmfs-release/cvmfs-release-latest.noarch.rpm \
-                   https://download.opensuse.org/repositories/home:/cvmfs:/contrib-egi/AlmaLinux_8/noarch/cvmfs-config-egi-2.7-1.8.obs.el8.noarch.rpm
-RUN dnf -y install cvmfs
+                   https://download.opensuse.org/repositories/home:/cvmfs:/contrib-egi/AlmaLinux_8/noarch/cvmfs-config-egi-2.7-1.8.obs.el8.noarch.rpm && \
+    # Install CVMFS
+    dnf -y install cvmfs && \
+    # Clean up cache to keep layer size small
+    dnf clean all && \
+    rm -rf /var/cache/dnf
 
-# EPEL
+# Install EPEL repository
 RUN dnf -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
 
 # Install HEP_OSlibs
-RUN dnf -y install https://linuxsoft.cern.ch/wlcg/centos8/x86_64/wlcg-repo-1.0.0-1.el8.noarch.rpm
-RUN dnf -y install --enablerepo=devel HEP_OSlibs
+RUN dnf -y install https://linuxsoft.cern.ch/wlcg/centos8/x86_64/wlcg-repo-1.0.0-1.el8.noarch.rpm && \
+    dnf -y install --enablerepo=devel HEP_OSlibs && \
+    # Clean up cache to keep layer size small
+    dnf clean all && \
+    rm -rf /var/cache/dnf
 
 # Boost (need to ensure gfal CLI from CVMFS will work for some VOs)
 RUN dnf -y install boost-date-time boost-filesystem boost-graph boost-iostreams boost-program-options \
                    boost-regex boost-serialization boost-signals boost-system boost-test \
-                   boost-thread boost-wave
-
-# Apptainer
-RUN dnf -y install apptainer
-
-# Disable overlay and loop device management in Apptainer
-RUN sed -i '/enable overlay/c\enable overlay = no' /etc/apptainer/apptainer.conf && \
-    sed -i '/enable underlay/c\enable underlay = yes' /etc/apptainer/apptainer.conf && \
-    sed -i '/max loop devices/c\max loop devices = 0' /etc/apptainer/apptainer.conf
+                   boost-thread boost-wave && \
+    # Clean up cache to keep layer size small
+    dnf clean all && \
+    rm -rf /var/cache/dnf
 
-# Deny setuid in Apptainer
-RUN sed -i '/allow setuid/c\allow setuid = no' /etc/apptainer/apptainer.conf
+# Install Apptainer
+RUN dnf -y install apptainer && \
+    # Clean up cache to keep layer size small
+    dnf clean all && \
+    rm -rf /var/cache/dnf
 
-# Update & cleanup
+# Update OS packages & tidy up
 RUN dnf -y update && \
     dnf clean all && \
     rm -rf /var/cache/dnf
 
-LABEL source=https://github.com/stfc/grid-workernode
-LABEL description="A specialised container image optimized for high-performance batch job execution in RAL's computing environment. \
-It includes essential software, libraries, and dependencies, ensuring efficient, and scalable job processing, benefiting researchers and organisations."
+# Create all possible pool accounts
+RUN curl -s https://raw.githubusercontent.com/stfc/grid-workernode/master/resources/pool_accounts/create.sh | bash -
diff --git a/docker-c9/Dockerfile b/docker-c9/Dockerfile
index e4195e0..21a9b8b 100644
--- a/docker-c9/Dockerfile
+++ b/docker-c9/Dockerfile
@@ -1,5 +1,11 @@
 FROM rockylinux:9
 
+# Add labels
+LABEL org.opencontainers.image.source=https://github.com/stfc/grid-workernode
+LABEL org.opencontainers.image.authors=gstsm@stfc.atlassian.net
+LABEL org.opencontainers.image.description="A specialised container image optimised for high-performance batch job execution in RAL's computing environment. \
+It includes essential software, libraries, and dependencies, ensuring efficient, and scalable job processing, benefiting researchers and organisations."
+
 # Basic dependencies
 RUN dnf -y install \
     zip \
@@ -15,44 +21,49 @@ RUN dnf -y install \
     attr \
     tcsh \
     numactl \
-    bc
-
-# Create all possible pool accounts
-RUN curl -s https://raw.githubusercontent.com/stfc/grid-workernode/master/resources/pool_accounts/create.sh | bash -
+    bc \
+    wget && \
+    # Clean up cache to keep layer size small
+    dnf clean all && \
+    rm -rf /var/cache/dnf
 
 # CVMFS (for SUM tests only; install before adding other repos to ensure we have the latest version)
 RUN dnf -y install https://ecsft.cern.ch/dist/cvmfs/cvmfs-release/cvmfs-release-latest.noarch.rpm \
-                   https://download.opensuse.org/repositories/home:/cvmfs:/contrib-egi/AlmaLinux_9/noarch/cvmfs-config-egi-2.7-1.8.obs.el9.noarch.rpm
-RUN dnf -y install cvmfs
+                   https://download.opensuse.org/repositories/home:/cvmfs:/contrib-egi/AlmaLinux_9/noarch/cvmfs-config-egi-2.7-1.8.obs.el9.noarch.rpm && \
+    # Install CVMFS
+    dnf -y install cvmfs && \
+    # Clean up cache to keep layer size small
+    dnf clean all && \
+    rm -rf /var/cache/dnf
 
-# EPEL
+# Install EPEL repository
 RUN dnf -y install https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm
 
 # Install HEP_OSlibs
-RUN dnf -y install https://linuxsoft.cern.ch/wlcg/el9/x86_64/wlcg-repo-1.0.0-1.el9.noarch.rpm
-RUN dnf -y install --enablerepo=devel HEP_OSlibs
+RUN dnf -y install https://linuxsoft.cern.ch/wlcg/el9/x86_64/wlcg-repo-1.0.0-1.el9.noarch.rpm && \
+    dnf -y install --enablerepo=devel HEP_OSlibs && \
+    # Clean up cache to keep layer size small
+    dnf clean all && \
+    rm -rf /var/cache/dnf
 
 # Boost (need to ensure gfal CLI from CVMFS will work for some VOs)
 RUN dnf -y install boost-date-time boost-filesystem boost-graph boost-iostreams boost-program-options \
                    boost-regex boost-serialization boost-system boost-test \
-                   boost-thread boost-wave
-
-# Apptainer
-RUN dnf -y install apptainer
-
-# Disable overlay and loop device management in Apptainer
-RUN sed -i '/enable overlay/c\enable overlay = no' /etc/apptainer/apptainer.conf && \
-    sed -i '/enable underlay/c\enable underlay = yes' /etc/apptainer/apptainer.conf && \
-    sed -i '/max loop devices/c\max loop devices = 0' /etc/apptainer/apptainer.conf
+                   boost-thread boost-wave && \
+    # Clean up cache to keep layer size small
+    dnf clean all && \
+    rm -rf /var/cache/dnf
 
-# Deny setuid in Apptainer
-RUN sed -i '/allow setuid/c\allow setuid = no' /etc/apptainer/apptainer.conf
+# Install Apptainer
+RUN dnf -y install apptainer && \
+    # Clean up cache to keep layer size small
+    dnf clean all && \
+    rm -rf /var/cache/dnf
 
-# Update & cleanup
+# Update OS packages & tidy up
 RUN dnf -y update && \
     dnf clean all && \
     rm -rf /var/cache/dnf
 
-LABEL source=https://github.com/stfc/grid-workernode
-LABEL description="A specialised container image optimized for high-performance batch job execution in RAL's computing environment. \
-It includes essential software, libraries, and dependencies, ensuring efficient, and scalable job processing, benefiting researchers and organisations."
+# Create all possible pool accounts
+RUN curl -s https://raw.githubusercontent.com/stfc/grid-workernode/master/resources/pool_accounts/create.sh | bash -
diff --git a/xrootd/Dockerfile b/xrootd/Dockerfile
index f5f5874..770d977 100644
--- a/xrootd/Dockerfile
+++ b/xrootd/Dockerfile
@@ -1,10 +1,18 @@
 FROM rockylinux:8
+
+# Add labels and arguments
 ARG XROOTD_VERSION=5.7.3-3
 ARG XRDCEPH_VERSION=5.7.3-3
 ARG CEPH_VERSION=14.2.22-0
+ARG ARCH=x86_64
+ARG DISTRO=el8
 LABEL xrootd-ver=$XROOTD_VERSION
 LABEL xrdceph-ver=$XRDCEPH_VERSION
 LABEL ceph-ver=$CEPH_VERSION
+LABEL org.opencontainers.image.source=https://github.com/stfc/grid-workernode
+LABEL org.opencontainers.image.authors=gstsm@stfc.atlassian.net
+LABEL org.opencontainers.image.description="A specialised container image optimised as a local XROOTD gateway in RAL's computing environment. \
+It includes software for XROOTD along with libraries, and dependencies, ensuring efficient, and scalable data staging, benefiting researchers and organisations."
 
 # xrootd user - needs to be consistent with the host
 RUN groupadd --gid 65432 xrootd && \
@@ -13,50 +21,52 @@ RUN groupadd --gid 65432 xrootd && \
 # Repositories
 COPY *.repo /etc/yum.repos.d/
 
-# install versionlock, and configure versionlocks
-RUN dnf -y install python3-dnf-plugin-versionlock
-RUN dnf -y versionlock add ceph-${CEPH_VERSION}.el8.x86_64 \
-                           ceph-base-${CEPH_VERSION}.el8.x86_64 \
-                           ceph-common-${CEPH_VERSION}.el8.x86_64 \
-                           ceph-mds-${CEPH_VERSION}.el8.x86_64 \
-                           ceph-mgr-${CEPH_VERSION}.el8.x86_64 \
-                           ceph-mon-${CEPH_VERSION}.el8.x86_64 \
-                           ceph-osd-${CEPH_VERSION}.el8.x86_64 \
-                           ceph-selinux-${CEPH_VERSION}.el8.x86_64 \
-                           libcephfs2-${CEPH_VERSION}.el8.x86_64 \
-                           librados2-${CEPH_VERSION}.el8.x86_64 \
-                           libradosstriper1-${CEPH_VERSION}.el8.x86_64 \
-                           librbd1-${CEPH_VERSION}.el8.x86_64 \
-                           librgw2-${CEPH_VERSION}.el8.x86_64 \
-                           python-ceph-argparse-${CEPH_VERSION}.el8.x86_64 \
-                           python-cephfs-${CEPH_VERSION}.el8.x86_64 \
-                           python-rados-${CEPH_VERSION}.el8.x86_64 \
-                           python-rbd-${CEPH_VERSION}.el8.x86_64 \
-                           python-rgw-${CEPH_VERSION}.el8.x86_64 \
-                           python3-ceph-argparse-${CEPH_VERSION}.el8.x86_64 \
-                           python3-cephfs-${CEPH_VERSION}.el8.x86_64 \
-                           python3-rados-${CEPH_VERSION}.el8.x86_64 \
-                           python3-rbd-${CEPH_VERSION}.el8.x86_64 \
-                           python3-rgw-${CEPH_VERSION}.el8.x86_64 \
-                           xrootd-${XROOTD_VERSION}.el8.x86_64 \
-                           xrootd-client-${XROOTD_VERSION}.el8.x86_64 \
-                           xrootd-client-libs-${XROOTD_VERSION}.el8.x86_64 \
-                           xrootd-libs-${XROOTD_VERSION}.el8.x86_64 \
-                           xrootd-selinux-${XROOTD_VERSION}.el8.noarch \
-                           xrootd-server-${XROOTD_VERSION}.el8.x86_64 \
-                           xrootd-server-libs-${XROOTD_VERSION}.el8.x86_64 \
-                           xrootd-ceph-buffered-${XRDCEPH_VERSION}.el8.x86_64 \
-                           xrootd-voms-${XROOTD_VERSION}.el8.x86_64 \
-                           xrootd-scitokens-${XROOTD_VERSION}.el8.x86_64
-
-RUN dnf -y versionlock list
-
+# Install versionlock, and configure versionlocks
+RUN dnf -y install python3-dnf-plugin-versionlock && \
+    dnf -y versionlock add ceph-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   ceph-base-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   ceph-common-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   ceph-mds-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   ceph-mgr-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   ceph-mon-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   ceph-osd-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   ceph-selinux-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   libcephfs2-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   librados2-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   libradosstriper1-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   librbd1-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   librgw2-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   python-ceph-argparse-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   python-cephfs-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   python-rados-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   python-rbd-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   python-rgw-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   python3-ceph-argparse-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   python3-cephfs-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   python3-rados-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   python3-rbd-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   python3-rgw-${CEPH_VERSION}.${DISTRO}.${ARCH} \
+                   xrootd-${XROOTD_VERSION}.${DISTRO}.${ARCH} \
+                   xrootd-client-${XROOTD_VERSION}.${DISTRO}.${ARCH} \
+                   xrootd-client-libs-${XROOTD_VERSION}.${DISTRO}.${ARCH} \
+                   xrootd-libs-${XROOTD_VERSION}.${DISTRO}.${ARCH} \
+                   xrootd-selinux-${XROOTD_VERSION}.${DISTRO}.noarch \
+                   xrootd-server-${XROOTD_VERSION}.${DISTRO}.${ARCH} \
+                   xrootd-server-libs-${XROOTD_VERSION}.${DISTRO}.${ARCH} \
+                   xrootd-ceph-buffered-${XRDCEPH_VERSION}.${DISTRO}.${ARCH} \
+                   xrootd-voms-${XROOTD_VERSION}.${DISTRO}.${ARCH} \
+                   xrootd-scitokens-${XROOTD_VERSION}.${DISTRO}.${ARCH} && \
+    # For debugging purposes, show the versionlock list
+    dnf -y versionlock list
 
-# Ceph
+# Install CEPH
 RUN dnf -y install ceph \
-                   ceph-common
+                   ceph-common && \
+                    # Clean up cache to keep layer size small
+                    dnf clean all && \
+                    rm -rf /var/cache/dnf
 
-# xrootd
+# Install XROOTD
 RUN dnf -y install xrootd-ceph-buffered \
                    xrootd-client \
                    xrootd-client-libs \
@@ -65,23 +75,34 @@ RUN dnf -y install xrootd-ceph-buffered \
                    xrootd-server-libs \
                    xrootd-voms \
                    xrootd-scitokens \
-                   jemalloc
-
+                   jemalloc && \
+                   # Clean up cache to keep layer size small
+                   dnf clean all && \
+                   rm -rf /var/cache/dnf
 
 # For N2N mapping
-RUN dnf -y install http://repos.gridpp.rl.ac.uk/yum/xrootd-cmstfc/el8/xrootd-cmstfc-1.5.2-6.osgroup.el8.x86_64.rpm
+RUN dnf -y install http://repos.gridpp.rl.ac.uk/yum/xrootd-cmstfc/${DISTRO}/xrootd-cmstfc-1.5.2-6.osgroup.${DISTRO}.${ARCH}.rpm
 
-# Needed by the health-check scripts
-RUN dnf -y install openssl
+# Required for health-check scripts
+RUN dnf -y install openssl && \
+                   # Clean up cache to keep layer size small
+                   dnf clean all && \
+                   rm -rf /var/cache/dnf
 
-# python3 needed for cephsum script
+# Python3 required for cephsum script
 RUN dnf -y install python3 \
-                   python3-rados
+                   python3-rados && \
+                   # Clean up cache to keep layer size small
+                   dnf clean all && \
+                   rm -rf /var/cache/dnf
 
 # Install netcat for service healthcheck
-RUN dnf -y install netcat
+RUN dnf -y install netcat && \
+                   # Clean up cache to keep layer size small
+                   dnf clean all && \
+                   rm -rf /var/cache/dnf
 
-# Update & cleanup
+# Update OS packages & tidy up
 RUN dnf -y update && \
                    dnf clean all && \
                    rm -rf /var/cache/dnf