Currently if there is any transient gossip failure in any node the
recoevry process depends on other nodes propogating the information
indirectly. In cases if these transient failures affects all the nodes
that this node has in its memberlist then this node will be permenantly
cutoff from the the gossip channel. Added node state management code in
networkdb to address these problems by trying to rejoin the cluster via
the failed nodes when there is a failure. This also necessitates the
need to add new messages called node event messages to differentiate
between node leave and node failure.
Signed-off-by: Jana Radhakrishnan <mrjana@docker.com>
Convert all networkdb core message types from go message types to
protobuf message types. This faciliates future modification of the
message structure without breaking backward compatibility.
Signed-off-by: Jana Radhakrishnan <mrjana@docker.com>
