remove --mount directives

These were added to speed up local image builds. However, it looks like
there is an interaction between runc and Buildah that prevents these
directives from being used (https://issues.redhat.com/browse/RHEL-129120).

Once that is resolved, we should revert this PR.

Author: cheesesashimi

Dockerfile

@@ -7,9 +7,7 @@ COPY . .
 # just use that.  For now we work around this by copying a tarball.
 ENV GOCACHE="/go/rhel9/.cache"
 ENV GOMODCACHE="/go/rhel9/pkg/mod"
-RUN --mount=type=cache,target=/go/rhel9/.cache,z \
-    --mount=type=cache,target=/go/rhel9/pkg/mod,z \
-    make install DESTDIR=./instroot-rhel9 && tar -C instroot-rhel9 -cf instroot-rhel9.tar .
+RUN make install DESTDIR=./instroot-rhel9 && tar -C instroot-rhel9 -cf instroot-rhel9.tar .
 
 # Add a RHEL 8 builder to compile the RHEL 8 compatible binaries
 FROM registry.ci.openshift.org/ocp/builder:rhel-8-golang-1.24-openshift-4.21 AS rhel8-builder
@@ -19,15 +17,12 @@ WORKDIR /go/src/github.com/openshift/machine-config-operator
 COPY . .
 ENV GOCACHE="/go/rhel8/.cache"
 ENV GOMODCACHE="/go/rhel8/pkg/mod"
-RUN --mount=type=cache,target=/go/rhel8/.cache,z \
-    --mount=type=cache,target=/go/rhel8/pkg/mod,z \
-    make install DESTDIR=./instroot-rhel8 && tar -C instroot-rhel8 -cf instroot-rhel8.tar .
+RUN make install DESTDIR=./instroot-rhel8 && tar -C instroot-rhel8 -cf instroot-rhel8.tar .
 
 FROM registry.ci.openshift.org/ocp/4.21:base-rhel9
 ARG TAGS=""
 COPY install /manifests
-RUN --mount=type=cache,target=/var/cache/dnf,z \
-    if [ "${TAGS}" = "fcos" ]; then \
+RUN if [ "${TAGS}" = "fcos" ]; then \
     # comment out non-base/extensions image-references entirely for fcos
     sed -i '/- name: rhel-coreos-/,+3 s/^/#/' /manifests/image-references && \
     # also remove extensions from the osimageurl configmap (if we don't, oc won't rewrite it, and the placeholder value will survive and get used)

Dockerfile.rhel7

@@ -8,9 +8,7 @@ COPY . .
 # just use that.  For now we work around this by copying a tarball.
 ENV GOCACHE="/go/rhel9/.cache"
 ENV GOMODCACHE="/go/rhel9/pkg/mod"
-RUN --mount=type=cache,target=/go/rhel9/.cache,z \
-    --mount=type=cache,target=/go/rhel9/pkg/mod,z \
-    make install DESTDIR=./instroot-rhel9 && tar -C instroot-rhel9 -cf instroot-rhel9.tar .
+RUN make install DESTDIR=./instroot-rhel9 && tar -C instroot-rhel9 -cf instroot-rhel9.tar .
 
 # Add a RHEL 8 builder to compile the RHEL 8 compatible binaries
 FROM registry.ci.openshift.org/ocp/builder:rhel-8-golang-1.24-openshift-4.21 AS rhel8-builder
@@ -20,15 +18,12 @@ WORKDIR /go/src/github.com/openshift/machine-config-operator
 COPY . .
 ENV GOCACHE="/go/rhel8/.cache"
 ENV GOMODCACHE="/go/rhel8/pkg/mod"
-RUN --mount=type=cache,target=/go/rhel8/.cache,z \
-    --mount=type=cache,target=/go/rhel8/pkg/mod,z \
-    make install DESTDIR=./instroot-rhel8 && tar -C instroot-rhel8 -cf instroot-rhel8.tar .
+RUN make install DESTDIR=./instroot-rhel8 && tar -C instroot-rhel8 -cf instroot-rhel8.tar .
 
 FROM registry.ci.openshift.org/ocp/4.21:base-rhel9
 ARG TAGS=""
 COPY install /manifests
-RUN --mount=type=cache,target=/var/cache/dnf,z \
-    if [ "${TAGS}" = "fcos" ]; then \
+RUN if [ "${TAGS}" = "fcos" ]; then \
     # comment out non-base/extensions image-references entirely for fcos
     sed -i '/- name: rhel-coreos-/,+3 s/^/#/' /manifests/image-references && \
     # also remove extensions from the osimageurl configmap (if we don't, oc won't rewrite it, and the placeholder value will survive and get used)
@@ -45,7 +40,8 @@ RUN --mount=type=cache,target=/var/cache/dnf,z \
     # Create the build user which will be used for doing OS image builds. We
     # use the username "build" and the uid 1000 since this matches what is in
     # the official Buildah image.
-    useradd --uid 1000 build
+    # Conditional checks if "build" user does not exist before adding user.
+    if ! id -u "build" >/dev/null 2>&1; then useradd --uid 1000 build; fi
 # Copy the binaries *after* we install nmstate so we don't invalidate our cache for local builds.
 COPY --from=rhel9-builder /go/src/github.com/openshift/machine-config-operator/instroot-rhel9.tar /tmp/instroot-rhel9.tar
 RUN cd / && tar xf /tmp/instroot-rhel9.tar && rm -f /tmp/instroot-rhel9.tar