Requirements

To be added as a node to the SKALE Network, a prospective node must run the SKALE Admin, which manages all operations in the node and is installed with the skale-node-cli. SKALE Admin evaluates the prospective node to ensure that it is upholding network hardware requirements. If the prospective node passes this verification step, the SKALE Admin permits the node to submit a request to SKALE Manager in order to join the network. This request contains both the required network deposit as well as node metadata collected by the SKALE Daemon (e.g., IP address, port, public key, etc.).

Once the request has been submitted to SKALE Manager on Ethereum, SKALE Manager randomly defines the prospective node as a 'full node' or a 'fractional node' by assigning different sizes of SKALE Chains to the prospective node. Full nodes have all of their resources utilized for a single Elastic Sidechain, while fractional nodes participate in multiple Elastic Sidechains (multi-tenancy).

After the node registration, the node receives an assigned group of random node peers to monitor. Peers regularly audit several metrics at predetermined periods (e.g. five minutes) and submit the batched metrics to the SKALE Manager once for every network epoch. The batched metrics are used to determine the node's bounty reward. Currently, each node will only monitor downtime and latency for the other node peers, and more metrics will be added throughout the Incentivized Devnet testing.

Hardware Requirements (Devnet)

External Storage

Docker has an easy way of limiting other machine resources such as CPU, memory, and volume. These resources are configurable through the docker set up. Configuring machine resources such as CPU and memory are easy to complete via the docker set up; however, configuring volume requires a few more steps.

To assist with configuring volume, SKALE Labs introduced Docker Convoy, Logical Volume Manager (LVM), and external disk space to format and partition disk space per SKALE Chain. Docker Convoy is a Docker volume plugin for a variety of storage backends. Docker Convoy supports vendor-specific extensions such as snapshots, backups, and restores.

When a validator sets up a node through the CLI, SKALE Admin calls the Docker Convoy to format the external volume. Each validator in the SKALE Network will be expected to provide non-boot external disk space, which will be used to partition the volume by the SKALE Admin.

Note: If you want to learn more about how our engineering team architected this solution for SKALE please check out our engineers blog here.
SKALE Admin calls Docker Convoy to limit disk space per container (for example 20GB). The Docker Convoy requests LVM to split the volume in 1/128 size partitions. Once LVM splits the container and allocates the new space to the SKALE Chain, LVM and Docker Convoy informs SKALE Admin that the disk is limited based on the configured SKALE Chain size.

SGX (HSM)

Software Guard Extension (SGX) is an Intel® technology coprocessor ledger used for memory encryption and increasing the security of application code by storing encrypted data in the processor. 

A SKALE sub-node connects to the SGX wallet server, and then the SGX wallet connects to the wallet enclave (BLS signatures and ETH keys). Keys stored in the processor cannot be taken out, and it can only be encrypted or decrypted through enclave. The key within the processor is secure in enclave, and hackers cannot hack the enclave and receive the key.

Without SGX, human confirmation is necessary for transactions made in the SKALE Network. SKALE uses SGX for securing cryptographic keys by allowing nodes to connect hardware wallets without human interaction. 

SKALE uses BLS to sign blocks in consensus, and ECDSA is needed to validate regular Ethereum's transactions. SKALE will have a separate wallet integration for ECDSA. SKALE will use Intel® SGX technology to store BLS signatures in the coprocessor level and let users automatically authorize transactions. Currently other than bare-metal servers, SGX is supported for these cloud providers.
(HSMs) Ledger Nano, or Trezor, can support ECDSA signatures but not BLS signatures, which are used by SKALE Consensus. We estimate that it will take a couple of years for these hardware devices to support BLS signatures.
Advantages of SGX Wallet:
SKALE will have two types of SGX operations: