New PeerManager, Allocator, Informer components have been added along
with a new "replication_factor" configuration option.
First, cluster peers collect and push metrics (Informer) to the Cluster
leader regularly. The Informer is an interface that can be implemented
in custom wayts to support custom metrics.
Second, on a pin operation, using the information from the collected metrics,
an Allocator can provide a list of preferences as to where the new pin
should be assigned. The Allocator is an interface allowing to provide
different allocation strategies.
Both Allocator and Informer are Cluster Componenets, and have access
to the RPC API.
The allocations are kept in the shared state. Cluster peer failure
detection is still missing and re-allocation is still missing, although
re-pinning something when a node is down/metrics missing does re-allocate
the pin somewhere else.
License: MIT
Signed-off-by: Hector Sanjuan <hector@protocol.ai>
At the beginning we opted for native types which were
serializable (PinInfo had a CidStr field instead of Cid).
Now we provide types in two versions: native and serializable.
Go methods use native. The rest of APIs (REST/RPC) use always
serializable versions. Methods are provided to convert between the
two.
The reason for moving these out of the way is to be able to re-use
type definitions when parsing API responses in `ipfs-cluster-ctl` or
any other clients that come up. API responses are just the serializable
version of types in JSON encoding. This also reduces having
duplicate types defs and parsing methods everywhere.
License: MIT
Signed-off-by: Hector Sanjuan <hector@protocol.ai>
This is the third implementation attempt. This time, rather than
broadcasting PeerAdd/Join requests to the whole cluster, we use the
consensus log to broadcast new peers joining.
This makes it easier to recover from errors and to know who exactly
is member of a cluster and who is not. The consensus is, after all,
meant to agree on things, and the list of cluster peers is something
everyone has to agree on.
Raft itself uses a special log operation to maintain the peer set.
The tests are almost unchanged from the previous attempts so it should
be the same, except it doesn't seem possible to bootstrap a bunch of nodes
at the same time using different bootstrap nodes. It works when using
the same. I'm not sure this worked before either, but the code is
simpler than recursively contacting peers, and scales better for
larger clusters.
Nodes have to be careful about joining clusters while keeping the state
from a different cluster (disjoint logs). This may cause problems with
Raft.
License: MIT
Signed-off-by: Hector Sanjuan <hector@protocol.ai>
This commit adds PeerAdd() and PeerRemove() endpoints, CLI support,
tests. Peer management is a delicate issue because of how the consensus
works underneath and the places that need to track such peers.
When adding a peer the procedure is as follows:
* Try to open a connection to the new peer and abort if not reachable
* Broadcast a PeerManagerAddPeer operation which tells all cluster members
to add the new Peer. The Raft leader will add it to Raft's peerset and
the multiaddress will be saved in the ClusterPeers configuration key.
* If the above fails because some cluster node is not responding,
broadcast a PeerRemove() and try to undo any damage.
* If the broadcast succeeds, send our ClusterPeers to the new Peer along with
the local multiaddress we are using in the connection opened in the
first step (that is the multiaddress through which the other peer can reach us)
* The new peer updates its configuration with the new list and joins
the consensus
License: MIT
Signed-off-by: Hector Sanjuan <hector@protocol.ai>
I have renamed "members" to "peers".
Added IPFS daemon ID and addresses to the ID object and
have Peers() return the collection of ID() objects from the cluster.
License: MIT
Signed-off-by: Hector Sanjuan <hector@protocol.ai>
The former RPC stuff had become a monster, really hard to have an overview
of the RPC api capabilities and with lots of magic.
go-libp2p-rpc allows to have a clearly defined RPC api which
shows which methods every component can use. A component to perform
remote requests, and the convoluted LeaderRPC, BroadcastRPC methods are
no longer necessary.
Things are much simpler now, less goroutines are needed, the central channel
handling bottleneck is gone, RPC requests are very streamlined in form.
In the future, it would be inmediate to have components living on different
libp2p hosts and it is way clearer how to plug into the advanced cluster rpc
api.
License: MIT
Signed-off-by: Hector Sanjuan <hector@protocol.ai>
