DNF update, install and clean in the same layer

for a significantly smaller image size.

Before:

ghcr.io/xcp-ng/xcp-ng-build-env             8.2            e985e704c252  10 minutes ago  1.03 GB
ghcr.io/xcp-ng/xcp-ng-build-env             8.3            b557dcb6d541  11 minutes ago  1.14 GB
ghcr.io/xcp-ng/xcp-ng-build-env             9.0            c738df7d5577  11 minutes ago  857 MB

After:

ghcr.io/xcp-ng/xcp-ng-build-env             8.2            a9a91fa03db8  7 seconds ago       491 MB
ghcr.io/xcp-ng/xcp-ng-build-env             8.3            a36b1399ac01  About a minute ago  557 MB
ghcr.io/xcp-ng/xcp-ng-build-env             9.0            78011dcbd6f3  11 minutes ago      708 MB

Signed-off-by: Gaëtan Lehmann <[email protected]>

Author: glehmann

src/xcp_ng_dev/files/Dockerfile-8.x

@@ -19,18 +19,15 @@ RUN     sed -i -e "s/@XCP_NG_BRANCH@/${XCP_NG_BRANCH}/g" /etc/yum.repos.d/xcp-ng
 # Install GPG key
 RUN     curl -sSf https://xcp-ng.org/RPM-GPG-KEY-xcpng -o /etc/pki/rpm-gpg/RPM-GPG-KEY-xcpng
 
-# Fix invalid rpmdb checksum error with overlayfs, see https://github.com/docker/docker/issues/10180
-# (still needed?)
-RUN     yum install -y yum-plugin-ovl
-
-# Use priorities so that packages from our repositories are preferred over those from CentOS repositories
-RUN     yum install -y yum-plugin-priorities
-
 # Update
-RUN     yum update -y
-
-# Common build requirements
-RUN     yum install -y \
+RUN     yum update -y \
+        # Fix invalid rpmdb checksum error with overlayfs, see https://github.com/docker/docker/issues/10180
+        # (still needed?)
+        && yum install -y yum-plugin-ovl \
+        # Use priorities so that packages from our repositories are preferred over those from CentOS repositories
+        && yum install -y yum-plugin-priorities \
+        # Common build requirements
+        && yum install -y \
             gcc \
             gcc-c++ \
             git \
@@ -41,16 +38,14 @@ RUN     yum install -y \
             sudo \
             yum-utils \
             epel-release \
-            epel-rpm-macros
-
-# Niceties
-RUN     yum install -y \
+            epel-rpm-macros \
+        # Niceties
+        && yum install -y \
             vim \
             wget \
-            which
-
-# clean package cache to avoid download errors
-RUN     yum clean all
+            which \
+        # clean package cache to avoid download errors
+        && yum clean all
 
 # OCaml in XS may be older than in CentOS
 RUN     sed -i "/gpgkey/a exclude=ocaml*" /etc/yum.repos.d/Cent* /etc/yum.repos.d/epel*

src/xcp_ng_dev/files/Dockerfile-9.x

@@ -10,10 +10,9 @@ COPY    files/Alma10-devel.repo /etc/yum.repos.d/
 RUN     curl -sSf https://xcp-ng.org/RPM-GPG-KEY-xcpng -o /etc/pki/rpm-gpg/RPM-GPG-KEY-xcpng
 
 # Update
-RUN     dnf update -y
-
-# Common build requirements
-RUN     dnf install -y \
+RUN     dnf update -y \
+        # Common build requirements
+        && dnf install -y \
             gcc \
             gcc-c++ \
             git \
@@ -23,28 +22,24 @@ RUN     dnf install -y \
             python3-rpm \
             sudo \
             dnf-plugins-core \
-            epel-release
-
-# EPEL: needs epel-release installed first
-RUN     dnf install -y \
+            epel-release \
+        # EPEL: needs epel-release installed first
+        && dnf install -y \
             epel-rpm-macros \
-            almalinux-git-utils
-
-# Niceties
-RUN     dnf install -y \
+            almalinux-git-utils \
+        # Niceties
+        && dnf install -y \
             bash-completion \
             vim \
             wget \
-            which
-
-# clean package cache to avoid download errors
-RUN     yum clean all
-
-# -release*, to be commented out to boostrap the build-env until it gets built
-# FIXME: isn't it already pulled as almalinux-release when available?
-RUN     dnf install -y \
+            which \
+        # -release*, to be commented out to boostrap the build-env until it gets built
+        # FIXME: isn't it already pulled as almalinux-release when available?
+        && dnf install -y \
             xcp-ng-release \
-            xcp-ng-release-presets
+            xcp-ng-release-presets \
+        # clean package cache to avoid download errors
+        && yum clean all
 
 # enable repositories commonly required to build
 RUN     dnf config-manager --enable crb