Inevitably a user will need more resources or want to yield resources to save currency. A user's preference for resources and her willingness to pay for those resources is a bid and the process of changing the bid is bidding. Note that this terminology differs from standard usage. This document only refers to changes in bids as bidding because bids in Tycoon persist until they expire.
A bid consists of a duration and a set of preferences for resources. A bid implicitly uses all of the currency in a host account for funding. The duration is amount of time until the bid expires. A preference specifies a type of resource, possibly a specific instance of the resources, the amount of currency to be spent for the resource, and the minimum and maximum resource requirements.
When a bid is initially sent, it can be admitted or rejected. The most common reason for rejection is bidding too little currency for too much of a scarce resource. Note that only one scarce resource may cause a bid with multiple preferences to be rejected. A user with sufficient flexibility can try again by submitting a new bid with more currency and/or a smaller minimum requirement. Once the bid is accepted, all of its preferences will be activated and the auctioneer will allocate appropriate amounts of all the resources (see Section 4.1.2, “Allocation, Usage, and Spending”).
Despite having been admitted, a bid may still have one or more of its preferences deactivated because of changes in resource scarcity. A host account that owns the deactivated preference will no longer receive the preference's resources. Table 4.1, “Preference Activation/Deactivation Effects” shows the exact effect for different resources.
| Resource | Activation Effect | Deactivation Effect |
|---|---|---|
| CPU | Nothing. | Virtual machine is shutdown. |
| Memory | Nothing. | Virtual machine is shutdown. |
| Disk | Nothing. | Host account is deleted. |
| TCPv4Port | Port is forwarded. | Port is no longer forwarded. |
| IPv4Address | DHCP lease is renewed. | DHCP lease is revoked. |
Table 4.1. Preference Activation/Deactivation Effects
Once the scarcity passes, the Auctioneer will activate the
preference, with the effects shown in Table 4.1, “Preference Activation/Deactivation Effects”. Note that the
activation and deactivation effects for some resources are
not inverse of each other, so a deactivation followed by an
activation will require user intervention to restore the
original state.
Regardless of preference activations and deactivations, a bid lasts for its entire duration. At the end of the duration, the bid expires and the duration is reset for a long time (currently 1Gs). Since this will probably decrease the preference bid amounts, some preferences may be deactivated, possibly causing the auctioneer to delete the account. Users should not rely on their accounts persisting beyond the expiration time.
If the host account runs out of funds, then the account is deleted.
The algorithm for computing allocations and payments is complicated and is TBD.