feat(dockerfile.*): ensure packages are cleaned up after installation

Do for all except Gentoo, for performance reasons when actually using
the test containers.

Dockerfile.apt

@@ -28,6 +28,7 @@ SHELL ["/bin/bash", "-x", "-o", "pipefail", "-c"]
 # hadolint ignore=SC1075,DL3008,DL4001
 RUN apt-get update \
  && apt-get install --yes --no-install-recommends $PKGS \
+ && apt-get clean \
     # Install Salt using the bootstrap script (removing the 10 seconds delay to cancel the bootstrap)
  && curl -L https://raw.githubusercontent.com/saltstack/salt-bootstrap/develop/bootstrap-salt.sh | \
     sed -e '/^\s\+echowarn "You have 10 seconds to cancel and stop the bootstrap process..."/,+2d' | \

Dockerfile.dnf

@@ -21,7 +21,9 @@ ARG SALT_REPO_URL=""
 
 SHELL ["/bin/bash", "-x", "-o", "pipefail", "-c"]
 # hadolint ignore=DL3041
-RUN dnf -y update && dnf -y install ${PKGS} --setopt=install_weak_deps=False && dnf clean all \
+RUN dnf -y update \
+ && dnf -y install ${PKGS} --setopt=install_weak_deps=False \
+ && dnf clean all \
     # Install Salt using the bootstrap script (removing the 10 seconds delay to cancel the bootstrap)
  && curl -L https://raw.githubusercontent.com/saltstack/salt-bootstrap/develop/bootstrap-salt.sh | \
     sed -e '/^\s\+echowarn "You have 10 seconds to cancel and stop the bootstrap process..."/,+2d' | \

Dockerfile.pac

@@ -23,6 +23,7 @@ SHELL ["/bin/bash", "-x", "-o", "pipefail", "-c"]
 RUN pacman --noconfirm -Sy archlinux-keyring \
  && pacman-db-upgrade \
  && pacman --noconfirm -Syu ${PKGS} \
+ && pacman -Scc \
     # Install Salt using the bootstrap script (removing the 10 seconds delay to cancel the bootstrap)
  && curl -L https://raw.githubusercontent.com/saltstack/salt-bootstrap/develop/bootstrap-salt.sh | \
     sed -e '/^\s\+echowarn "You have 10 seconds to cancel and stop the bootstrap process..."/,+2d' | \

Dockerfile.yum

@@ -26,6 +26,7 @@ RUN if [[ "${DISTRO_NAME}" = "centos" ]]; then \
       yum -y install epel-release; \
     fi \
  && yum -y install ${PKGS} \
+ && yum clean all \
     # Install Salt using the bootstrap script (removing the 10 seconds delay to cancel the bootstrap)
  && curl -L https://raw.githubusercontent.com/saltstack/salt-bootstrap/develop/bootstrap-salt.sh | \
     sed -e '/^\s\+echowarn "You have 10 seconds to cancel and stop the bootstrap process..."/,+2d' | \

Dockerfile.zyp

@@ -21,7 +21,9 @@ ARG SALT_REPO_URL=""
 
 SHELL ["/bin/bash", "-x", "-o", "pipefail", "-c"]
 # hadolint ignore=DL3037
-RUN zypper refresh && zypper install --no-recommends -y ${PKGS} && zypper clean \
+RUN zypper refresh \
+ && zypper install --no-recommends -y ${PKGS} \
+ && zypper clean \
  && systemctl enable sshd \
     # https://github.com/inspec/train/issues/377
     # https://github.com/inspec/train/pull/505