private RestApiException restApiExceptionWithDenialReason(
            String operationDescription,
            HostName hostName,
            HostStateChangeDeniedException e) {
        return createRestApiException(operationDescription, hostName, e, e.getConstraintName(), e.getMessage(),
                Response.Status.CONFLICT);
    }
Resume normal operations for all services on a host that has previously been allowed suspension.

If the host is already registered as running normal operations, then resume() is idempotent
and will succeed.
orchestrator/src/main/java/com/yahoo/vespa/orchestrator/resources/HostRequestHandler.java