In order to do so IPFS Cluster server nodes use a libp2p-based consensus algorithm (currently Raft) to agree on a log of operations and build a consistent state across the cluster. The state represents which objects should be pinned by which nodes.
Additionally, server nodes act as a proxy/wrapper to the IPFS API, so they can be used as a regular node, with the difference that pin requests are handled by the Cluster.
IPFS Cluster provides a server application (`ipfscluster-server`), a Go API, a HTTP API and a command-line tool (`ipfscluster`).
Current functionality only allows pinning in all cluster members, but more strategies (like setting a replication factor for each pin) will be developed.
Since the start of IPFS it was clear that a tool to coordinate a number of different nodes (and the content they are supposed to store) would add a great value to the IPFS ecosystem. Naïve approaches are possible, but they present some weaknesses, specially at dealing with error handling and incorporating multiple pinning strategies.
`ipfs-cluster` aims to address this issues by providing a IPFS node wrapper which coordinates multiple cluster members via a consensus algorithm. This ensures that the desired state of the system is always agreed upon and can be easily maintained by the members of the cluster. Thus, every cluster member has an overview of where each hash is pinned, and the cluster can react to any contingencies, like IPFS nodes dying, by redistributing the storage load to others.
`ipfscluster-server` runs a member node for the cluster. Usage information can be obtained running:
```
$ ipfscluster-server -h
```
Before running `ipfscluster-server` for the first time, initialize a configuration file with:
```
$ ipfscluster-server -init
```
The configuration will be placed in `~/.ipfs-cluster/server.json`.
You can add the multiaddresses for the other members of the cluster in the `cluster_peers` variable.
### `ipfscluster`
`ipfscluster` is the client application to manage the cluster servers and perform actions. `ipfscluster` uses the HTTP API provided by the server nodes.
TODO: This is not done yet
### Go
IPFS Cluster nodes can be launched directly from Go. The `Cluster` object provides methods to interact with the cluster and perform actions.
Documentation and examples on how to use IPFS Cluster from Go can be found in [godoc.org/github.com/ipfs/ipfs-cluster](https://godoc.org/github.com/ipfs/ipfs-cluster).
