Clustertools image size could be optimized

[kosstennbl]

Clustertools image size is ~ 2.1GB, which has to be downloaded and extracted.
Possibly it can be made smaller for faster usage and less space consumption.

Improvement possibilities:
Join layers for Wireshark installation, for external tools download.
Use --no-install-recommends with apt when installing packages.
Remove all the packages needed for build after building Wireshark.
Remove tar archives for external tools.
Remove source code of Wireshark and OpenMetricsValidator after build.

[martin-mat]

cloning/checking out of wireshark can be optimized. The key is in those 2 layers:

RUN git clone https://github.com/wireshark/wireshark.git /wireshark
RUN cd /wireshark && \
    git checkout tags/wireshark-4.0.8 && \
    mkdir build && \
    cd build && \
    cmake ../ && \
    make -j`nproc` && \
    make install

to something like this:

RUN git clone https://github.com/wireshark/wireshark.git --branch wireshark-4.0.8 --depth 1 --single-branch /wireshark &&
    cd /wireshark && \
    mkdir build && \
    cd build && \
    cmake ../ && \
    make -j`nproc` && \
    make install && \
    cd / &&
    rm -rf /wireshark

That would save probably about 2.5G from the image size.

[horecoli]

I believe that a multi-stage build can be used for building Wireshark, where only the binary is copied to a new Debian image. This can be done similarly to how it is done with the validator.