I certainly may not have run the qubesctl command correctly, but the gui based update utility also fails. I had changed the default disposable template to fedora-34-qubes-core. Does it need to be a centos-8 template to work?
[root@dom0 ~]# qubesctl --skip-dom0 --targets=centos-8 --show-output --force-color state.sls update.qubes-vm centos-8: centos-8: ---------- _error: Failed to return clean data retcode: 1 stderr: Traceback (most recent call last): File "/var/tmp/.root_dd8a91_salt/pyall/salt/loader_context.py", line 10, in <module> import _contextvars as contextvars ModuleNotFoundError: No module named '_contextvars' During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/var/tmp/.root_dd8a91_salt/salt-call", line 27, in <module> salt_call() File "/var/tmp/.root_dd8a91_salt/pyall/salt/scripts.py", line 437, in salt_call import salt.cli.call File "/var/tmp/.root_dd8a91_salt/pyall/salt/cli/call.py", line 6, in <module> import salt.cli.caller File "/var/tmp/.root_dd8a91_salt/pyall/salt/cli/caller.py", line 14, in <module> import salt.loader File "/var/tmp/.root_dd8a91_salt/pyall/salt/loader.py", line 29, in <module> import salt.loader_context File "/var/tmp/.root_dd8a91_salt/pyall/salt/loader_context.py", line 13, in <module> import contextvars File "/var/tmp/.root_dd8a91_salt/py3/contextvars.py", line 1, in <module> from _contextvars import Context, ContextVar, Token, copy_context ModuleNotFoundError: No module named '_contextvars' stdout: [root@dom0 ~]# -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/CA%2BVdTb9htOT37wfMxtUHBFSgM%3DgNgzKKLwv%2Bdzzjag3sSCL%3DBQ%40mail.gmail.com.
[root@dom0 ~]# qubesctl --skip-dom0 --targets=centos-8 --show-output --force-color state.sls update.qubes-vm centos-8: centos-8: ---------- _error: Failed to return clean data retcode: 1 stderr: Traceback (most recent call last): File "/var/tmp/.root_dd8a91_salt/pyall/salt/loader_context.py", line 10, in <module> import _contextvars as contextvars ModuleNotFoundError: No module named '_contextvars' During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/var/tmp/.root_dd8a91_salt/salt-call", line 27, in <module> salt_call() File "/var/tmp/.root_dd8a91_salt/pyall/salt/scripts.py", line 437, in salt_call import salt.cli.call File "/var/tmp/.root_dd8a91_salt/pyall/salt/cli/call.py", line 6, in <module> import salt.cli.caller File "/var/tmp/.root_dd8a91_salt/pyall/salt/cli/caller.py", line 14, in <module> import salt.loader File "/var/tmp/.root_dd8a91_salt/pyall/salt/loader.py", line 29, in <module> import salt.loader_context File "/var/tmp/.root_dd8a91_salt/pyall/salt/loader_context.py", line 13, in <module> import contextvars File "/var/tmp/.root_dd8a91_salt/py3/contextvars.py", line 1, in <module> from _contextvars import Context, ContextVar, Token, copy_context ModuleNotFoundError: No module named '_contextvars' stdout: [root@dom0 ~]#