restarting all specific units on systemctl without for loop?

UPDATE Systemd supports wildcards from systemd-209 forward https://serverfault.com/a/797926/291826

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Two years later systemctl still doesn't allow wildcards, even though they would be extremely useful.

I did however take your note about systemctl -t service --failed and I hacked together this. I decided to post it here because the next person to find this question could be helped by it.

systemctl restart $(systemctl -t service --failed | grep openstack-nova-*.service | cut -d ' ' -f 1)

This takes systemctl -t service --failed, greps for the services matching "openstack-nova-*.service" and then removes the descriptors of those files by cutting (cut) on the space (-d ' ') and taking the first result (-f 1). Then it restarts the whole bunch because thankfully systemctl command allows for multiple services to be passed to it to stop.