binpath and variant

[tisonkun]

I wonder if gtctl can -

• specify the binpath of greptimedb in use
• specify the variant (with PyO3 backend, centos image) in use

.. or we are currently fixedly using some default. If so, what's the default?

cc @zyy17

[zyy17]

@tisonkun, the gtctl will choose the binary and docker images that users mostly use; for example, we use the binary without the pyo3 backend(it's easy to set up) and the ubuntu-based docker image as the default option. Also, the gtctl has the option to specify the binary or docker image, for example:

• bare-metal deployment: you can use the config file to control the local binary;

• K8s deployment: you can use the following command to set image:

  gtctl cluster create mycluster \
    --set cluster.image.repository=greptime/greptimedb \
   --set cluster.image.tag=latest
  

Both configurations are not easy to use. I think we should refactor the configurations in the future.