What happens when a parachain's lease runs out?

Question

As the first batch of leases come to a close in the next few months for the first batch of parachains on Kusama ( https://parachains.info/auctions/kusama-1-5 ),

• what can we expect in terms of timings as to when they might have to take actions if they want to re-lease?
• what actions would they likely have to take
• and should we anticipate any interruption of service from those parachains?

(It would be great if answers can include concrete dates concerning this first batch.)

Answer 1

"At the conclusion of the lease, the slot will go back up for auction and the team will need to bid for a slot again if they wish to retain one. Parachain slots are fungible, so teams do not need to always bid on the same slot. To avoid any downtime in connectivity and minimize the risk of losing a subsequent auction, teams can bid on and secure an adjacent slot before their current lease period ends."

So concretely, another slot would be won via the standard auction system in the usual way and then at the point when the lease runs out the parachain would swap from one slot to the next. (The parachain's locked crowdloan would be made available such that people could choose to back the parachain's bid of a new slot)

It is the pallet paras_registrar.swap function which carries out the action defined here:

https://github.com/paritytech/polkadot/blob/64059a2fab9878ffde4971db0c3dc15bcb4282f4/runtime/common/src/paras_registrar.rs#L274

Remember parachains are not forced to renew, - they could become a self sovereign solo chain or swap to be a parathread (once parathreads are enabled via on-chain governance).

Answer 2

when a parachain lease runs out then simply your parachain block producion is stop that is best block which shown in the top of the explorer. there is a some ways to do when your lease period runs out...

Auction Process: Before the lease period ends, an auction is typically held to determine which parachain will be allocated the slot next. This auction allows parachain projects to bid for a lease extension or a new slot on the network.

Slot Reassignment: Once the auction concludes, the winning parachain is assigned the slot previously occupied by the expiring parachain. This ensures continuous operation of the network and allows new projects to join.

Parachain Removal: After the slot is reassigned, the expiring parachain is removed from the network. This removal involves detaching the parachain's state and stopping the validation and block production activities associated with it.

State Backup: Before removal, it is common for the parachain's state to be backed up. This ensures that the historical data and state of the expiring parachain are preserved for future reference or potential reintegration.