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We strongly recommend all users to use the new generic hostnames for our Atos HPCF service instead of the specific complex login nodes. You may use hpc-login for interactive login access and hpc-batch for remote batch submission, which will always point to an available complex
Note that after the session, the shorthand hostnames such as aa.ecmwf.int will also be retired in favour of the alternatives described in HPC2020: How to connect.
You have more information on how to connect to the Atos HCPF in HPC2020: How to connectin the HPCF Documentation pages.