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.
Restore a few more service-kind index updates so blocking in ServiceDump works in more cases
Namely one omission was that check updates for dumped services were not
unblocking.
Also adds a ServiceDump state store test and also fix a watch bug with the
normal dump.
Follow-on from #6916
When there is an node name conflicts, such messages are displayed within Consul:
`consul.fsm: EnsureRegistration failed: failed inserting node: Error while renaming Node ID: "e1d456bc-f72d-98e5-ebb3-26ae80d785cf": Node name node001 is reserved by node 05f10209-1b9c-b90c-e3e2-059e64556d4a with name node001`
While it is easy to find the node that has reserved the name, it is hard to find
the node trying to aquire the name since it is not registered, because it
is not part of `consul members` output
This PR will display the IP of the offender and solve far more easily those issues.
* Ensure the mesh gateway configuration comes back in the api within each upstream
* Add a test for the MeshGatewayConfig in the ToAPI functions
* Ensure we don’t use gateways for dc local connections
* Update the svc kind index for deletions
* Replace the proxycfg.state cache with an interface for testing
Also start implementing proxycfg state testing.
* Update the state tests to verify some gateway watches for upstream-targets of a discovery chain.
Fixes: #4222
# Data Filtering
This PR will implement filtering for the following endpoints:
## Supported HTTP Endpoints
- `/agent/checks`
- `/agent/services`
- `/catalog/nodes`
- `/catalog/service/:service`
- `/catalog/connect/:service`
- `/catalog/node/:node`
- `/health/node/:node`
- `/health/checks/:service`
- `/health/service/:service`
- `/health/connect/:service`
- `/health/state/:state`
- `/internal/ui/nodes`
- `/internal/ui/services`
More can be added going forward and any endpoint which is used to list some data is a good candidate.
## Usage
When using the HTTP API a `filter` query parameter can be used to pass a filter expression to Consul. Filter Expressions take the general form of:
```
<selector> == <value>
<selector> != <value>
<value> in <selector>
<value> not in <selector>
<selector> contains <value>
<selector> not contains <value>
<selector> is empty
<selector> is not empty
not <other expression>
<expression 1> and <expression 2>
<expression 1> or <expression 2>
```
Normal boolean logic and precedence is supported. All of the actual filtering and evaluation logic is coming from the [go-bexpr](https://github.com/hashicorp/go-bexpr) library
## Other changes
Adding the `Internal.ServiceDump` RPC endpoint. This will allow the UI to filter services better.
* Make Connect health queryies unblock correctly in all cases and use optimal number of watch chans. Fixes#5506.
* Node check test cases and clearer bug test doc
* Comment update
Refs #4984.
Watching chans for every node we touch in a health query is wasteful. In #4984 it shows that if there are more than 682 service instances we always fallback to watching all services which kills performance.
We already have a record in MemDB that is reliably update whenever the service health result should change thanks to per-service watch indexes.
So in general, provided there is at least one service instances and we actually have a service index for it (we always do now) we only ever need to watch a single channel.
This saves us from ever falling back to the general index and causing the performance cliff in #4984, but it also means fewer goroutines and work done for every blocking health query.
It also saves some allocations made during the query because we no longer have to populate a WatchSet with 3 chans per service instance which saves the internal map allocation.
This passes all state store tests except the one that explicitly checked for the fallback behaviour we've now optimized away and in general seems safe.
Node updates were not updating the service indexes, which are used for
service related queries. This caused the X-Consul-Index to stay the same
after a node update as seen from a service query even though the node
data is returned in heath queries. If that happened in between queries
the client would miss this change.
We now update the indexes of the services on the node when it is
updated.
Fixes: #5450
## Background
When making a blocking query on a missing service (was never registered, or is not registered anymore) the query returns as soon as any service is updated.
On clusters with frequent updates (5~10 updates/s in our DCs) these queries virtually do not block, and clients with no protections againt this waste ressources on the agent and server side. Clients that do protect against this get updates later than they should because of the backoff time they implement between requests.
## Implementation
While reducing the number of unnecessary updates we still want :
* Clients to be notified as soon as when the last instance of a service disapears.
* Clients to be notified whenever there's there is an update for the service.
* Clients to be notified as soon as the first instance of the requested service is added.
To reduce the number of unnecessary updates we need to block when a request to a missing service is made. However in the following case :
1. Client `client1` makes a query for service `foo`, gets back a node and X-Consul-Index 42
2. `foo` is unregistered
3. `client1` makes a query for `foo` with `index=42` -> `foo` does not exist, the query blocks and `client1` is not notified of the change on `foo`
We could store the last raft index when each service was last alive to know wether we should block on the incoming query or not, but that list could grow indefinetly.
We instead store the last raft index when a service was unregistered and use it when a query targets a service that does not exist.
When a service `srv` is unregistered this "missing service index" is always greater than any X-Consul-Index held by the clients while `srv` was up, allowing us to immediatly notify them.
1. Client `client1` makes a query for service `foo`, gets back a node and `X-Consul-Index: 42`
2. `foo` is unregistered, we set the "missing service index" to 43
3. `client1` makes a blocking query for `foo` with `index=42` -> `foo` does not exist, we check against the "missing service index" and return immediatly with `X-Consul-Index: 43`
4. `client1` makes a blocking query for `foo` with `index=43` -> we block
5. Other changes happen in the cluster, but foo still doesn't exist and "missing service index" hasn't changed, the query is still blocked
6. `foo` is registered again on index 62 -> `foo` exists and its index is greater than 43, we unblock the query
* Support multiple tags for health and catalog api endpoints
Fixes#1781.
Adds a `ServiceTags` field to the ServiceSpecificRequest to support
multiple tags, updates the filter logic in the catalog store, and
propagates these change through to the health and catalog endpoints.
Note: Leaves `ServiceTag` in the struct, since it is being used as
part of the DNS lookup, which in turn uses the health check.
* Update the api package to support multiple tags
Includes additional tests.
* Update new tests to use the `require` library
* Update HealthConnect check after a bad merge
* [Performance On Large clusters] Checks do update services/nodes only when really modified to avoid too many updates on very large clusters
In a large cluster, when having a few thousands of nodes, the anti-entropy
mechanism performs lots of changes (several per seconds) while
there is no real change. This patch wants to improve this in order
to increase Consul scalability when using many blocking requests on
health for instance.
* [Performance for large clusters] Only updates index of service if service is really modified
* [Performance for large clusters] Only updates index of nodes if node is really modified
* Added comments / ensure IsSame() has clear semantics
* Avoid having modified boolean, return nil directly if stutures are Same
* Fixed unstable unit tests TestLeader_ChangeServerID
* Rewrite TestNode_IsSame() for better readability as suggested by @banks
* Rename ServiceNode.IsSame() into IsSameService() + added unit tests
* Do not duplicate TestStructs_ServiceNode_Conversions() and increase test coverage of IsSameService
* Clearer documentation in IsSameService
* Take into account ServiceProxy into ServiceNode.IsSameService()
* Fixed IsSameService() with all new structures
* Display more information about check being not properly added when it fails
It follows an incident where we add lots of error messages:
[WARN] consul.fsm: EnsureRegistration failed: failed inserting check: Missing service registration
That seems related to Consul failing to restart on respective agents.
Having Node information as well as service information would help diagnose the issue.
* Renamed ensureCheckIfNodeMatches() as requested by @banks
* Allow to rename nodes with IDs, will fix#3974 and #4413
This change allow to rename any well behaving recent agent with an
ID to be renamed safely, ie: without taking the name of another one
with case insensitive comparison.
Deprecated behaviour warning
----------------------------
Due to asceding compatibility, it is still possible however to
"take" the name of another name by not providing any ID.
Note that when not providing any ID, it is possible to have 2 nodes
having similar names with case differences, ie: myNode and mynode
which might lead to DB corruption on Consul server side and
lead to server not properly restarting.
See #3983 and #4399 for Context about this change.
Disabling registration of nodes without IDs as specified in #4414
should probably be the way to go eventually.
* Removed the case-insensitive search when adding a node within the else
block since it breaks the test TestAgentAntiEntropy_Services
While the else case is probably legit, it will be fixed with #4414 in
a later release.
* Added again the test in the else to avoid duplicated names, but
enforce this test only for nodes having IDs.
Thus most tests without any ID will work, and allows us fixing
* Added more tests regarding request with/without IDs.
`TestStateStore_EnsureNode` now test registration and renaming with IDs
`TestStateStore_EnsureNodeDeprecated` tests registration without IDs
and tests removing an ID from a node as well as updated a node
without its ID (deprecated behaviour kept for backwards compatibility)
* Do not allow renaming in case of conflict, including when other node has no ID
* Fixed function GetNodeID that was not working due to wrong type when searching node from its ID
Thus, all tests about renaming were not working properly.
Added the full test cas that allowed me to detect it.
* Better error messages, more tests when nodeID is not a valid UUID in GetNodeID()
* Added separate TestStateStore_GetNodeID to test GetNodeID.
More complete test coverage for GetNodeID
* Added new unit test `TestStateStore_ensureNoNodeWithSimilarNameTxn`
Also fixed comments to be clearer after remarks from @banks
* Fixed error message in unit test to match test case
* Use uuid.ParseUUID to parse Node.ID as requested by @mkeeler
Since DNS is case insensitive and DB as issues when similar names with different
cases are added, check for unicity based on case insensitivity.
Following another big incident we had in our cluster, we also validate
that adding/renaming a not does not conflicts with case insensitive
matches.
We had the following error once:
- one node called: mymachine.MYDC.mydomain was shut off
- another node (different ID) was added with name: mymachine.mydc.mydomain before
72 hours
When restarting the consul server of domain, the consul server restarted failed
to start since it detected an issue in RAFT database because
mymachine.MYDC.mydomain and mymachine.mydc.mydomain had the same names.
Checking at registration time with case insensitivity should definitly fix
those issues and avoid Consul DB corruption.
Bugfix for https://github.com/hashicorp/consul/pull/3899
When a node level check is removed (example: maintenance),
some watchers on services might have to recompute their state.
If those nodes are performing blocking queries, they have to be notified.
While their state was updated when node-level state did change or was added
this was not the case when the check was removed. This fixes it.
This patch did give some better results, but break watches on
the services of a node.
It is possible to apply the same optimization for nodes than
to services (one index per instance), but it would complicate
further the patch.
Let's do it in another PR.
This patch improves the watches for services on large cluster:
each service has now its own index, such watches on a specific service
are not modified by changes in the global catalog.
It should improve a lot the performance of tools such as consul-template
or libraries performing watches on very large clusters with many
services/watches.
Emre Savcı