Dockerfile optimization (kubernetes-sigs#9821)

Reducing the number of layers, increasing readability, reducing the size of the image (how much I can’t check, it’s impossible for me to build due to the unavailability of the vagrant repository)

pipeline.Dockerfile

@@ -2,50 +2,42 @@
 FROM ubuntu:focal-20220531
 
 ARG ARCH=amd64
-ARG TZ=Etc/UTC
-RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
-
-ENV VAGRANT_VERSION=2.3.4
-ENV VAGRANT_DEFAULT_PROVIDER=libvirt
-ENV VAGRANT_ANSIBLE_TAGS=facts
-
-RUN apt update -y \
-    && apt install -y \
-    libssl-dev python3-dev sshpass apt-transport-https jq moreutils wget libvirt-dev openssh-client rsync git \
-    ca-certificates curl gnupg2 software-properties-common python3-pip unzip \
-    && rm -rf /var/lib/apt/lists/*
-RUN curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add - \
-    && add-apt-repository \
-    "deb [arch=$ARCH] https://download.docker.com/linux/ubuntu \
-    $(lsb_release -cs) \
-    stable" \
-    && apt update -y && apt-get install --no-install-recommends -y docker-ce \
-    && rm -rf /var/lib/apt/lists/*
 
 # Some tools like yamllint need this
 # Pip needs this as well at the moment to install ansible
 # (and potentially other packages)
 # See: https://github.com/pypa/pip/issues/10219
-ENV LANG=C.UTF-8
+ENV VAGRANT_VERSION=2.3.4 \
+    VAGRANT_DEFAULT_PROVIDER=libvirt \
+    VAGRANT_ANSIBLE_TAGS=facts \ 
+    LANG=C.UTF-8 \
+    DEBIAN_FRONTEND=noninteractive
+
+RUN apt update && apt install -y \
+    libssl-dev python3-dev python3-pip sshpass apt-transport-https jq moreutils libvirt-dev openssh-client rsync git \
+    ca-certificates curl gnupg2 software-properties-common unzip \
+    && curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add - \
+    && add-apt-repository "deb [arch=$ARCH] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" \
+    && apt update && apt install --no-install-recommends -y docker-ce \
+    && apt autoremove -yqq --purge && apt clean && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /kubespray
-COPY . .
-RUN /usr/bin/python3 -m pip install --no-cache-dir pip -U \
-    && /usr/bin/python3 -m pip install --no-cache-dir -r tests/requirements.txt \
-    && python3 -m pip install --no-cache-dir -r requirements.txt \
-    && update-alternatives --install /usr/bin/python python /usr/bin/python3 1
 
-RUN KUBE_VERSION=$(sed -n 's/^kube_version: //p' roles/kubespray-defaults/defaults/main.yaml) \
-    && curl -LO https://storage.googleapis.com/kubernetes-release/release/$KUBE_VERSION/bin/linux/$ARCH/kubectl \
-    && chmod a+x kubectl \
-    && mv kubectl /usr/local/bin/kubectl
-
-# Install Vagrant
-RUN wget https://releases.hashicorp.com/vagrant/${VAGRANT_VERSION}/vagrant_${VAGRANT_VERSION}-1_amd64.deb && \
- dpkg -i vagrant_${VAGRANT_VERSION}-1_amd64.deb && \
- rm vagrant_${VAGRANT_VERSION}-1_amd64.deb && \
- vagrant plugin install vagrant-libvirt
+COPY . .
 
-# Install Kubernetes collections
-RUN pip3 install kubernetes \
-    && ansible-galaxy collection install kubernetes.core
+RUN update-alternatives --install /usr/bin/python python /usr/bin/python3 1 \
+    && pip install --no-cache-dir pip -U \
+    && pip install --no-cache-dir -r tests/requirements.txt -r requirements.txt \
+    && KUBE_VERSION=$(sed -n 's/^kube_version: //p' roles/kubespray-defaults/defaults/main.yaml) \
+    && curl -L https://storage.googleapis.com/kubernetes-release/release/$KUBE_VERSION/bin/linux/$ARCH/kubectl -o /usr/local/bin/kubectl\
+    && chmod a+x /usr/local/bin/kubectl \
+    # Install Vagrant
+    && curl -LO https://releases.hashicorp.com/vagrant/${VAGRANT_VERSION}/vagrant_${VAGRANT_VERSION}-1_amd64.deb \
+    && dpkg -i vagrant_${VAGRANT_VERSION}-1_amd64.deb \
+    && rm vagrant_${VAGRANT_VERSION}-1_amd64.deb \
+    && vagrant plugin install vagrant-libvirt \
+    # Install Kubernetes collections
+    && pip install --no-cache-dir kubernetes \
+    && ansible-galaxy collection install kubernetes.core \
+    # Clean cache python
+    && find / -type d -name '*__pycache__' -prune -exec rm -rf {} \;