Commit Graph

6 Commits

Author SHA1 Message Date
Daniel Nephin 8654adfc53 Handle FSM.Apply errors in raftApply
Previously we were inconsistently checking the response for errors. This
PR moves the response-is-error check into raftApply, so that all callers
can look at only the error response, instead of having to know that
errors could come from two places.

This should expose a few more errors that were previously hidden because
in some calls to raftApply we were ignoring the response return value.

Also handle errors more consistently. In some cases we would log the
error before returning it. This can be very confusing because it can
result in the same error being logged multiple times. Instead return
a wrapped error.
2021-04-20 13:29:29 -04:00
R.B. Boyer 0247f409a0
server: when wan federating via mesh gateways only do heuristic primary DC bypass on the leader (#9366)
Fixes #9341
2021-01-22 10:03:24 -06:00
André Cruz a64686fab6
testing: Fix govet errors 2020-08-21 18:01:55 +01:00
R.B. Boyer 3ad570ba99
server: don't activate federation state replication or anti-entropy until all servers are running 1.8.0+ (#8014) 2020-06-04 16:05:27 -05:00
R.B. Boyer 813d69622e
agent: handle re-bootstrapping in a secondary datacenter when WAN federation via mesh gateways is configured (#7931)
The main fix here is to always union the `primary-gateways` list with
the list of mesh gateways in the primary returned from the replicated
federation states list. This will allow any replicated (incorrect) state
to be supplemented with user-configured (correct) state in the config
file. Eventually the game of random selection whack-a-mole will pick a
winning entry and re-replicate the latest federation states from the
primary. If the user-configured state is actually the incorrect one,
then the same eventual correct selection process will work in that case,
too.

The secondary fix is actually to finish making wanfed-via-mgws actually
work as originally designed. Once a secondary datacenter has replicated
federation states for the primary AND managed to stand up its own local
mesh gateways then all of the RPCs from a secondary to the primary
SHOULD go through two sets of mesh gateways to arrive in the consul
servers in the primary (one hop for the secondary datacenter's mesh
gateway, and one hop through the primary datacenter's mesh gateway).
This was neglected in the initial implementation. While everything
works, ideally we should treat communications that go around the mesh
gateways as just provided for bootstrapping purposes.

Now we heuristically use the success/failure history of the federation
state replicator goroutine loop to determine if our current mesh gateway
route is working as intended. If it is, we try using the local gateways,
and if those don't work we fall back on trying the primary via the union
of the replicated state and the go-discover configuration flags.

This can be improved slightly in the future by possibly initializing the
gateway choice to local on startup if we already have replicated state.
This PR does not address that improvement.

Fixes #7339
2020-05-27 11:31:10 -05:00
R.B. Boyer a7fb26f50f
wan federation via mesh gateways (#6884)
This is like a Möbius strip of code due to the fact that low-level components (serf/memberlist) are connected to high-level components (the catalog and mesh-gateways) in a twisty maze of references which make it hard to dive into. With that in mind here's a high level summary of what you'll find in the patch:

There are several distinct chunks of code that are affected:

* new flags and config options for the server

* retry join WAN is slightly different

* retry join code is shared to discover primary mesh gateways from secondary datacenters

* because retry join logic runs in the *agent* and the results of that
  operation for primary mesh gateways are needed in the *server* there are
  some methods like `RefreshPrimaryGatewayFallbackAddresses` that must occur
  at multiple layers of abstraction just to pass the data down to the right
  layer.

* new cache type `FederationStateListMeshGatewaysName` for use in `proxycfg/xds` layers

* the function signature for RPC dialing picked up a new required field (the
  node name of the destination)

* several new RPCs for manipulating a FederationState object:
  `FederationState:{Apply,Get,List,ListMeshGateways}`

* 3 read-only internal APIs for debugging use to invoke those RPCs from curl

* raft and fsm changes to persist these FederationStates

* replication for FederationStates as they are canonically stored in the
  Primary and replicated to the Secondaries.

* a special derivative of anti-entropy that runs in secondaries to snapshot
  their local mesh gateway `CheckServiceNodes` and sync them into their upstream
  FederationState in the primary (this works in conjunction with the
  replication to distribute addresses for all mesh gateways in all DCs to all
  other DCs)

* a "gateway locator" convenience object to make use of this data to choose
  the addresses of gateways to use for any given RPC or gossip operation to a
  remote DC. This gets data from the "retry join" logic in the agent and also
  directly calls into the FSM.

* RPC (`:8300`) on the server sniffs the first byte of a new connection to
  determine if it's actually doing native TLS. If so it checks the ALPN header
  for protocol determination (just like how the existing system uses the
  type-byte marker).

* 2 new kinds of protocols are exclusively decoded via this native TLS
  mechanism: one for ferrying "packet" operations (udp-like) from the gossip
  layer and one for "stream" operations (tcp-like). The packet operations
  re-use sockets (using length-prefixing) to cut down on TLS re-negotiation
  overhead.

* the server instances specially wrap the `memberlist.NetTransport` when running
  with gateway federation enabled (in a `wanfed.Transport`). The general gist is
  that if it tries to dial a node in the SAME datacenter (deduced by looking
  at the suffix of the node name) there is no change. If dialing a DIFFERENT
  datacenter it is wrapped up in a TLS+ALPN blob and sent through some mesh
  gateways to eventually end up in a server's :8300 port.

* a new flag when launching a mesh gateway via `consul connect envoy` to
  indicate that the servers are to be exposed. This sets a special service
  meta when registering the gateway into the catalog.

* `proxycfg/xds` notice this metadata blob to activate additional watches for
  the FederationState objects as well as the location of all of the consul
  servers in that datacenter.

* `xds:` if the extra metadata is in place additional clusters are defined in a
  DC to bulk sink all traffic to another DC's gateways. For the current
  datacenter we listen on a wildcard name (`server.<dc>.consul`) that load
  balances all servers as well as one mini-cluster per node
  (`<node>.server.<dc>.consul`)

* the `consul tls cert create` command got a new flag (`-node`) to help create
  an additional SAN in certs that can be used with this flavor of federation.
2020-03-09 15:59:02 -05:00