Resolving systemd service ordering cycle conflict

I have two service files (serva and servb) as shown below. I want serva to start first (on boot, once network is available), and servb to start only after serva has started. This should be easy, but after playing with several service file parameters I'm still facing this error: > serva.service: Job servb.service/start deleted to break ordering > cycle starting with serva.service/start How do I fix servb.service to achieve what I want? the **serva.service** file is: [Unit] Description=Test Service A (serva) ConditionPathExists=/usr/local/serva ConditionFileIsExecutable=/usr/local/serva/serva ConditionPathIsReadWrite=/tmp Requires=network.target After=network-online.target postgresql.service multi-user.target Wants=postgresql.service [Service] Type=forking PIDFile=/run/serva.pid WorkingDirectory=/usr/local/serva ExecStartPre=/bin/sleep 10 ExecStart=/usr/local/serva/serva SuccessExitStatus=129 200 [Install] WantedBy=multi-user.target The **servb.service** file is: [Unit] Description=Test Service B (servb) ConditionPathExists=/usr/local/servb ConditionFileIsExecutable=/usr/local/servb ConditionPathIsReadWrite=/var/tmp Requires=serva.service After=serva.service [Service] Type=forking PIDFile=/run/servb.pid WorkingDirectory=/usr/local/servb ExecStart=/usr/local/servb/servb SuccessExitStatus=129 200 [Install] WantedBy=serva.service I tried modifying servb to use PartOf=haast.service instead of Requires=, but no change in behaviour. I suspect the 10 second delay in serva is contributing to the problem (but this is essential).