This change updates tests to honor `BootstrapExpect` exclusively when
forming test clusters and removes test only knobs, e.g.
`config.DevDisableBootstrap`.
Background:
Test cluster creation is fragile. Test servers don't follow the
BootstapExpected route like production clusters. Instead they start as
single node clusters and then get rejoin and may risk causing brain
split or other test flakiness.
The test framework expose few knobs to control those (e.g.
`config.DevDisableBootstrap` and `config.Bootstrap`) that control
whether a server should bootstrap the cluster. These flags are
confusing and it's unclear when to use: their usage in multi-node
cluster isn't properly documented. Furthermore, they have some bad
side-effects as they don't control Raft library: If
`config.DevDisableBootstrap` is true, the test server may not
immediately attempt to bootstrap a cluster, but after an election
timeout (~50ms), Raft may force a leadership election and win it (with
only one vote) and cause a split brain.
The knobs are also confusing as Bootstrap is an overloaded term. In
BootstrapExpect, we refer to bootstrapping the cluster only after N
servers are connected. But in tests and the knobs above, it refers to
whether the server is a single node cluster and shouldn't wait for any
other server.
Changes:
This commit makes two changes:
First, it relies on `BootstrapExpected` instead of `Bootstrap` and/or
`DevMode` flags. This change is relatively trivial.
Introduce a `Bootstrapped` flag to track if the cluster is bootstrapped.
This allows us to keep `BootstrapExpected` immutable. Previously, the
flag was a config value but it gets set to 0 after cluster bootstrap
completes.
Introduce limits to prevent unauthorized users from exhausting all
ephemeral ports on agents:
* `{https,rpc}_handshake_timeout`
* `{http,rpc}_max_conns_per_client`
The handshake timeout closes connections that have not completed the TLS
handshake by the deadline (5s by default). For RPC connections this
timeout also separately applies to first byte being read so RPC
connections with TLS enabled have `rpc_handshake_time * 2` as their
deadline.
The connection limit per client prevents a single remote TCP peer from
exhausting all ephemeral ports. The default is 100, but can be lowered
to a minimum of 26. Since streaming RPC connections create a new TCP
connection (until MultiplexV2 is used), 20 connections are reserved for
Raft and non-streaming RPCs to prevent connection exhaustion due to
streaming RPCs.
All limits are configurable and may be disabled by setting them to `0`.
This also includes a fix that closes connections that attempt to create
TLS RPC connections recursively. While only users with valid mTLS
certificates could perform such an operation, it was added as a
safeguard to prevent programming errors before they could cause resource
exhaustion.
Copy the updated version of freeport (sdk/freeport), and tweak it for use
in Nomad tests. This means staying below port 10000 to avoid conflicts with
the lib/freeport that is still transitively used by the old version of
consul that we vendor. Also provide implementations to find ephemeral ports
of macOS and Windows environments.
Ports acquired through freeport are supposed to be returned to freeport,
which this change now also introduces. Many tests are modified to include
calls to a cleanup function for Server objects.
This should help quite a bit with some flakey tests, but not all of them.
Our port problems will not go away completely until we upgrade our vendor
version of consul. With Go modules, we'll probably do a 'replace' to swap
out other copies of freeport with the one now in 'nomad/helper/freeport'.
Adds new package that can be used by client and server RPC endpoints to
facilitate monitoring based off of a logger
clean up old code
small comment about write
rm old comment about minsize
rename to Monitor
Removes connection logic from monitor command
Keep connection logic in endpoints, use a channel to send results from
monitoring
use new multisink logger and interfaces
small test for dropped messages
update go-hclogger and update sink/intercept logger interfaces
Adds nomad monitor command. Like consul monitor, this command allows you
to stream logs from a nomad agent in real time with a a specified log
level
add endpoint tests
Upgrade go-hclog to latest version
The current version of go-hclog pads log prefixes to equal lengths
so info becomes [INFO ] and debug becomes [DEBUG]. This breaks
hashicorp/logutils/level.go Check function. Upgrading to the latest
version removes this padding and fixes log filtering that uses logutils
Check
AgentMonitor is an endpoint to stream logs for a given agent. It allows
callers to pass in a supplied log level, which may be different than the
agents config allowing for temporary debugging with lower log levels.
Pass in logWriter when setting up Agent
Consul Connect must route traffic between network namespaces through a
public interface (i.e. not localhost). In order to support testing in
dev mode, users needed to manually set the interface which doesn't
make for a smooth experience.
This commit adds a facility for adding optional parameters to the
`nomad agent -dev` flag and uses it to add a `-dev=connect` flag that
binds to a public interface on the host.
Noticed few places where tests seem to block indefinitely and panic
after the test run reaches the test package timeout.
I intend to follow up with the proper fix later, but timing out is much
better than indefinitely blocking.
Mahmood Ali