Creating a conda environment is taking a long time

[rswamina]

The conda environment creation during development mode installation is taking hours. Should I wait or kill the process?

[rswamina]

Conda environment installation of the tool can take time but not several hours. You could try stopping, removing any partially created environment with a conda remove and try again.
You could also check where it is stalling to identify any specific problems.

[bouweandela]

Since this is still a popular topic: we now recommend using mamba instead of conda, as it is much faster. Installation should finish within minutes with a fast internet connection. Read more about it in our installation instructions.

[alistairsellar]

Related to this topic, a warning for future users who like to take shortcuts: If, like me, you thought that using the Jaspy installation of conda on Jasmin might save you time, don't bother. It's an old version of conda and you can't update it. For me, it lead to an eternity of "Solving environment"...

[alistairsellar]

When using my own conda installation on Jasmin, the "common issues" tips on this tutorial page solved my problem for a basic installation (no ESMValTool branch). Specifically, I needed to add the python=3.9 package spec as a positional argument:

conda create -n esmvaltool -c conda-forge -c esmvalgroup esmvaltool-python python=3.9

[alistairsellar]

However, when trying a development install, this command

conda env create -n a_new_name --file environment.yml

from the Development and contribution section, the same problem needs to be solved. The obvious solution is to include a python=3.9 package spec like in the basic install, but it can't go in the conda env create command line as a positional argument like in the above conda create command. Instead, I added it to the environment.yml file as the first dependency:

dependencies:
  # Python packages that cannot be installed from PyPI:
  - python=3.9
  - cartopy>=0.18

[bouweandela]

There is some advice available on this topic in the installation FAQ. If even that fails, you could try using mamba, it's quite fast (see #1907).

[valeriupredoi]

we have now solved this problem, and in the very near future will will adopt mamba that is much faster than conda, and uses the same API. We just need to test it carefully first but things are looking up already 👍

[ledm]

Mamba is the correct answer for me! It runs so much quicker than conda for stuff like conda env install or conda env update.

[ehogan]

Just in case it is helpful, what works well for me is to specify only the conda-forge channel, for example:

conda create --name esmvaltool-2.3.0 --override-channels -c conda-forge python=3.9 esmvaltool=2.3.0

This takes about 15 minutes to complete and works for ESMValTool v2.4.0 as well :)

[valeriupredoi]

@ehogan and others, with the release of v2.4.0 we have moved to a pure mamba/mambaforge installation procedure: what used to be miniconda it is now mambaforge, and what used to be calls to conda it is now calls to mamba (yes, we like snakes 🐍 ). So I recommend you guys use those new instructions; of course there are variations depending on what the user prefers: you can still use miniconda but install mamba and use it as a dependency solver/environment builder. In all cases, try to not use conda env create or conda create or conda env update anymore (with or without forcing Python version at CL point) since conda is getting harder and harder to work with. We have, of course, run a whole lot of env consistency tests before adopting mamba so rest assured all things will work well 🍺

[valeriupredoi]

Installation instructions