As part of removing the legacy ACL system ACL upgrading and the flag for
legacy ACLs is removed from Clients.
This commit also removes the 'acls' serf tag from client nodes. The tag is only ever read
from server nodes.
This commit also introduces a constant for the acl serf tag, to make it easier to track where
it is used.
The DebugConfig in the self endpoint can change at any time. It's not a stable API.
This commit adds the XDSPort to a stable part of the XDS api, and changes the envoy command to read
this new field.
It includes support for the old API as well, in case a newer CLI is used with an older API, and
adds a test for both cases.
Signed-off-by: Jakub Sokołowski <jakub@status.im>
* agent: add failures_before_warning setting
The new setting allows users to specify the number of check failures
that have to happen before a service status us updated to be `warning`.
This allows for more visibility for detected issues without creating
alerts and pinging administrators. Unlike the previous behavior, which
caused the service status to not update until it reached the configured
`failures_before_critical` setting, now Consul updates the Web UI view
with the `warning` state and the output of the service check when
`failures_before_warning` is breached.
The default value of `FailuresBeforeWarning` is the same as the value of
`FailuresBeforeCritical`, which allows for retaining the previous default
behavior of not triggering a warning.
When `FailuresBeforeWarning` is set to a value higher than that of
`FailuresBeforeCritical it has no effect as `FailuresBeforeCritical`
takes precedence.
Resolves: https://github.com/hashicorp/consul/issues/10680
Signed-off-by: Jakub Sokołowski <jakub@status.im>
Co-authored-by: Jakub Sokołowski <jakub@status.im>
This field has been unnecessary for a while now. It was always set to the same value
as PrimaryDatacenter. So we can remove the duplicate field and use PrimaryDatacenter
directly.
This change was made by GoLand refactor, which did most of the work for me.
The blocking query backend sets the default value on the server side.
The streaming backend does not using blocking queries, so we must set the timeout on
the client.
This field was documented as enabling TLS for outgoing RPC, but that was not the case.
All this field did was set the use_tls serf tag.
Instead of setting this field in a place far from where it is used, move the logic to where
the serf tag is set, so that the code is much more obvious.
tlsutil.Config already presents an excellent structure for this
configuration. Copying the runtime config fields to agent/consul.Config
makes code harder to trace, and provides no advantage.
Instead of copying the fields around, use the tlsutil.Config struct
directly instead.
This is one small step in removing the many layers of duplicate
configuration.
The bulk of this commit is moving the LeaderRoutineManager from the agent/consul package into its own package: lib/gort. It also got a renaming and its Start method now requires a context. Requiring that context required updating a whole bunch of other places in the code.
* Save exposed HTTP or GRPC ports to the agent's store
* Add those the health checks API so we can retrieve them from the API
* Change redirect-traffic command to also exclude those ports from inbound traffic redirection when expose.checks is set to true.
* WIP reloadable raft config
* Pre-define new raft gauges
* Update go-metrics to change gauge reset behaviour
* Update raft to pull in new metric and reloadable config
* Add snapshot persistance timing and installSnapshot to our 'protected' list as they can be infrequent but are important
* Update telemetry docs
* Update config and telemetry docs
* Add note to oldestLogAge on when it is visible
* Add changelog entry
* Update website/content/docs/agent/options.mdx
Co-authored-by: Matt Keeler <mkeeler@users.noreply.github.com>
Co-authored-by: Matt Keeler <mkeeler@users.noreply.github.com>
This adds support for the Incremental xDS protocol when using xDS v3. This is best reviewed commit-by-commit and will not be squashed when merged.
Union of all commit messages follows to give an overarching summary:
xds: exclusively support incremental xDS when using xDS v3
Attempts to use SoTW via v3 will fail, much like attempts to use incremental via v2 will fail.
Work around a strange older envoy behavior involving empty CDS responses over incremental xDS.
xds: various cleanups and refactors that don't strictly concern the addition of incremental xDS support
Dissolve the connectionInfo struct in favor of per-connection ResourceGenerators instead.
Do a better job of ensuring the xds code uses a well configured logger that accurately describes the connected client.
xds: pull out checkStreamACLs method in advance of a later commit
xds: rewrite SoTW xDS protocol tests to use protobufs rather than hand-rolled json strings
In the test we very lightly reuse some of the more boring protobuf construction helper code that is also technically under test. The important thing of the protocol tests is testing the protocol. The actual inputs and outputs are largely already handled by the xds golden output tests now so these protocol tests don't have to do double-duty.
This also updates the SoTW protocol test to exclusively use xDS v2 which is the only variant of SoTW that will be supported in Consul 1.10.
xds: default xds.Server.AuthCheckFrequency at use-time instead of construction-time
Setting this field to a value is equivalent to using the 'near' query paramter.
The intent is to sort the results by proximity to the node requesting
them. However with connect we send the results to envoy, which doesn't
care about the order, so setting this field is increasing the work
performed for no gain.
It is necessary to unset this field now because we would like connect
to use streaming, but streaming does not support sorting by proximity.
* add http2 ping checks
* fix test issue
* add h2ping check to config resources
* add new test and docs for h2ping
* fix grammatical inconsistency in H2PING documentation
* resolve rebase conflicts, add test for h2ping tls verification failure
* api documentation for h2ping
* update test config data with H2PING
* add H2PING to protocol buffers and update changelog
* fix typo in changelog entry
The streaming cache type for service health has no way to handle v1/health/ingress/:service queries as there is no equivalent topic that would return the appropriate data.
Ensure that attempts to use this endpoint will use the old cache-type for now so that they return appropriate data when streaming is enabled.
Some TLS servers require SNI, but the Golang HTTP client doesn't
include it in the ClientHello when connecting to an IP address. This
change adds a new TLSServerName field to health check definitions to
optionally set it. This fixes#9473.
Previously the ServiceManager had to run a separate goroutine so that it could block on a channel
send/receive instead of a lock. Using this mutex with TryLock allows us to cancel the lock when
the serviceConfigWatch is stopped.
Without this change removing the ServiceManager.Start goroutine would not be possible because
when AddService is called it acquires the stateLock. While that lock is held, if there are
existing watches for the service, the old watch will be stopped, and the goroutine holding the
lock will attempt to wait for that watcher goroutine to exit.
If the goroutine is handling an update (serviceConfigWatch.handleUpdate) then it can block on
acquiring the stateLock and deadlock the agent. With this change the context is cancelled as
and the goroutine will exit instead of waiting on the stateLock.
The ServiceManager.Start goroutine was used to serialize calls to
agent.addServiceInternal.
All the goroutines which sent events to the channel would block waiting
for a response from that same goroutine, which is effectively the same
as a synchronous call without any channels.
This commit removes the goroutine and channels, and instead calls
addServiceInternal directly. Since all of these goroutines will need to
take the agent.stateLock, the mutex handles the serializing of calls.
Move the field into the struct for addServiceLocked. Also don't require
setting a default value, so that the callers can leave it as nil if they
don't already have a snapshot.
Handle the decision to use ServiceManager in a single place. Instead of
calling ServiceManager.AddService, then calling back into
addServiceInternal, only call ServiceManager.AddService if we are going
to use it.
This change removes some small duplication and removes a branch from the
AddService flow.
The temprorary variables make it much harder to trace where and how struct
fields are used. If a field is only used a small number of times than
refer to the field directly.
The method is only used in tests, and only exists for legacy calls.
There was one other package which used this method in tests. Export
the AddServiceRequest and a couple of its fields so the new function can
be used in those tests.
I believe this commit also fixes a bug. Previously RPCMaxConnsPerClient was not being re-read from the RuntimeConfig, so passing it to Server.ReloadConfig was never changing the value.
Also improve the test runtime by not doing a lot of unnecessary work.
* create consul version metric with version label
* agent/agent.go: add pre-release Version as well as label
Co-Authored-By: Radha13 <kumari.radha3@gmail.com>
* verion and pre-release version labels.
* hyphen/- breaks prometheus
* Add Prometheus gauge defintion for version metric
* Add new metric to telemetry docs
Co-authored-by: Radha Kumari <kumari.radha3@gmail.com>
Co-authored-by: Aestek <thib.gilles@gmail.com>
Co-authored-by: Daniel Nephin <dnephin@hashicorp.com>
Previously the listener was being passed to a closure in a loop without
capturing the loop variable. The result is only the last listener is
used, so the http/https servers only listen on one address.
This problem is fixed by capturing the variable by passing it into a
function.
When a service is deregistered, we check whever matching services were
registered as sidecar along with it and deregister them as well.
To determine if a service is indeed a sidecar we check the
structs.ServiceNode.LocallyRegisteredAsSidecar property. However, to
avoid interal API leakage, it is excluded from JSON serialization,
meaning it is not persisted to disk either.
When the agent is restarted, this property lost and sidecars are no
longer deregistered along with their parent service.
To fix this, we now specifically save this property in the persisted
service file.
This allows for client agent to be run in a more stateless manner where they may be abruptly terminated and not expected to come back. If advertising a per-agent reconnect timeout using the advertise_reconnect_timeout configuration when that agent leaves, other agents will wait only that amount of time for the agent to come back before reaping it.
This has the advantageous side effect of causing servers to deregister the node/services/checks for that agent sooner than if the global reconnect_timeout was used.
This new package provides a client agent implementation of an interface
for fetching the health of services.
This approach has a number of benefits:
1. It provides a much more explicit interface. Instead of everything
dependency on `RPC()` and `Cache.Get()` for many unrelated things
they can depend on a type that are named according to the behaviour
it provides.
2. It gives us a single place to vary the behaviour and migrate to
a new form of RPC (gRPC). The current implementation has two options
(cache, or direct RPC), and in the future we will have more.
It is also a great opporunity to start adding `context.Context` args
to these operations, which in the future will allow us to cancel
the operations.
3. As a concequence of the first, in the Server agent where we make
these calls we can replace the current in-memory RPC calls with
a thin adapter for the real method. This removes the `net/rpc`
machinery from the call in places where it is not needed.
This new package is quite small right now, but I think we can expect it
to grow to a more reasonable size as other RPC calls are replaced.
This change also happens to replace two very similar implementations with
a single implementation.
In an upcoming change we will need to pass a grpc.ClientConnPool from
BaseDeps into Server. While looking at that change I noticed all of the
existing consulOption fields are already on BaseDeps.
Instead of duplicating the fields, we can create a struct used by
agent/consul, and use that struct in BaseDeps. This allows us to pass
along dependencies without translating them into different
representations.
I also looked at moving all of BaseDeps in agent/consul, however that
created some circular imports. Resolving those cycles wouldn't be too
bad (it was only an error in agent/consul being imported from
cache-types), however this change seems a little better by starting to
introduce some structure to BaseDeps.
This change is also a small step in reducing the scope of Agent.
Also remove some constants that were only used by tests, and move the
relevant comment to where the live configuration is set.
Removed some validation from NewServer and NewClient, as these are not
really runtime errors. They would be code errors, which will cause a
panic anyway, so no reason to handle them specially here.
And into token.Store. This change isolates any awareness of token
persistence in a single place.
It is a small step in allowing Agent.New to accept its dependencies.
This will apply cache throttling parameters are properly applied:
* cache.EntryFetchMaxBurst
* cache.EntryFetchRate
When values are updated, a log is displayed in info.
This might be better handled by allowing configuration for the InMemSink interval and retail, and disabling
the global. For now this is a smaller change to remove the goroutine leak caused by tests because go-metrics
does not provide any way of shutting down the global goroutine.
With this change, Agent.New() accepts many of the dependencies instead
of creating them in New. Accepting fully constructed dependencies from
a constructor makes the type easier to test, and easier to change.
There are still a number of dependencies created in Start() which can
be addressed in a follow up.
Previsouly it was done in Agent.Start, which is much later then it needs to be.
The new 'dns' package was required, because otherwise there would be an
import cycle. In the future we should move more of the dns server into
the dns package.
There are a couple reasons for this change:
1. agent.go is way too big. Smaller files makes code eaasier to read
because tools that show usage also include filename which can give
a lot more context to someone trying to understand which functions
call other functions.
2. these two functions call into a large number of functions already in
keyring.go.
This is a small step to allowing Agent to accept its dependencies
instead of creating them in New.
There were two fields in autoconfig.Config that were used exclusively
to load config. These were replaced with a single function, allowing us
to move LoadConfig back to the config package.
Also removed the WithX functions for building a Config. Since these were
simple assignment, it appeared we were not getting much value from them.
Making these functions allows us to cleanup how an agent is initialized. They only make use of a config and a logger, so they do not need to be agent methods.
Also cleanup the testing to use t.Run and require.
Now that it is no longer used, we can remove this unnecessary field. This is a pre-step in cleanup up RuntimeConfig->Consul.Config, which is a pre-step to adding a gRPCHandler component to Server for streaming.
Removing this field also allows us to remove one of the return values from logging.Setup.
Most of the groundwork was laid in previous PRs between adding the cert-monitor package to extracting the logic of signing certificates out of the connect_ca_endpoint.go code and into a method on the server.
This also refactors the auto-config package a bit to split things out into multiple files.
This implements a solution for #7863
It does:
Add a new config cache.entry_fetch_rate to limit the number of calls/s for a given cache entry, default value = rate.Inf
Add cache.entry_fetch_max_burst size of rate limit (default value = 2)
The new configuration now supports the following syntax for instance to allow 1 query every 3s:
command line HCL: -hcl 'cache = { entry_fetch_rate = 0.333}'
in JSON
{
"cache": {
"entry_fetch_rate": 0.333
}
}
The fallback method would still work but it would get into a state where it would let the certificate expire for 10s before getting a new one. And the new one used the less secure RPC endpoint.
This is also a pretty large refactoring of the auto encrypt code. I was going to write some tests around the certificate monitoring but it was going to be impossible to get a TestAgent configured in such a way that I could write a test that ran in less than an hour or two to exercise the functionality.
Moving the certificate monitoring into its own package will allow for dependency injection and in particular mocking the cache types to control how it hands back certificates and how long those certificates should live. This will allow for exercising the main loop more than would be possible with it coupled so tightly with the Agent.
In all cases (oss/ent, client/server) this method was returning a value from config. Since the
value is consistent, it doesn't need to be part of the delegate interface.
Fixes#7527
I want to highlight this and explain what I think the implications are and make sure we are aware:
* `HTTPConnStateFunc` closes the connection when it is beyond the limit. `Close` does not block.
* `HTTPConnStateFuncWithDefault429Handler(10 * time.Millisecond)` blocks until the following is done (worst case):
1) `conn.SetDeadline(10*time.Millisecond)` so that
2) `conn.Write(429error)` is guaranteed to timeout after 10ms, so that the http 429 can be written and
3) `conn.Close` can happen
The implication of this change is that accepting any new connection is worst case delayed by 10ms. But only after a client reached the limit already.
The embedded HTTPServer struct is not used by the large HTTPServer
struct. It is used by tests and the agent. This change is a small first
step in the process of removing that field.
The eventual goal is to reduce the scope of HTTPServer making it easier
to test, and split into separate packages.
The initial auto encrypt CSR wasn’t containing the user supplied IP and DNS SANs. This fixes that. Also We were configuring a default :: IP SAN. This should be ::1 instead and was fixed.
There are a couple of things in here.
First, just like auto encrypt, any Cluster.AutoConfig RPC will implicitly use the less secure RPC mechanism.
This drastically modifies how the Consul Agent starts up and moves most of the responsibilities (other than signal handling) from the cli command and into the Agent.
Right now this is only hooked into the insecure RPC server and requires JWT authorization. If no JWT authorizer is setup in the configuration then we inject a disabled “authorizer” to always report that JWT authorization is disabled.
Three of the checks are temporarily disabled to limit the size of the
diff, and allow us to enable all the other checks in CI.
In a follow up we can fix the issues reported by the other checks one
at a time, and enable them.
Based on work done in https://github.com/hashicorp/memberlist/pull/196
this allows to restrict the IP ranges that can join a given Serf cluster
and be a member of the cluster.
Restrictions on IPs can be done separatly using 2 new differents flags
and config options to restrict IPs for LAN and WAN Serf.
Previously this happened to be using the method on the Server/Client that was meant to allow the ACLResolver to locally resolve tokens. On Servers that had tokens (primary or secondary dc + token replication) this function would lookup the token from raft and return the ACLIdentity. On clients this was always a noop. We inadvertently used this function instead of creating a new one when we added logging accessor ids for permission denied RPC requests.
With this commit, a new method is used for resolving the identity properly via the ACLResolver which may still resolve locally in the case of being on a server with tokens but also supports remote token resolution.
Previously the SupportsBlocking option was specified by a method on the
type, and all the other options were specified from RegisterOptions.
This change moves RegisterOptions to a method on the type, and moves
SupportsBlocking into the options struct.
Currently there are only 2 cache-types. So all cache-types can implement
this method by embedding a struct with those predefined values. In the
future if a cache type needs to be registered more than once with different
options it can remove the embedded type and implement the method in a way
that allows for paramaterization.
* Implements a simple, tcp ingress gateway workflow
This adds a new type of gateway for allowing Ingress traffic into Connect from external services.
Co-authored-by: Chris Piraino <cpiraino@hashicorp.com>
The Init method provided the same functionality as the New constructor.
The constructor is both more widely used, and more idiomatic, so remove
the Init method.
This change is in preparation for fixing printing of these IDs.
Exposing checks is supposed to allow a Consul agent bound to a different
IP address (e.g., in a different Kubernetes pod) to access healthchecks
through the proxy while the underlying service binds to localhost. This
is an important security feature that makes sure no external traffic
reaches the service except through the proxy.
However, as far as I can tell, this is subtly broken in the case where
the Consul agent cannot reach the proxy over localhost.
If a proxy is configured with: `{ LocalServiceAddress: "127.0.0.1",
Checks: true }`, as is typical with a sidecar proxy, the Consul checks
are currently rewritten to `127.0.0.1:<random port>`. A Consul agent
that does not share the loopback address cannot reach this address. Just
to make sure I was not misunderstanding, I tried configuring the proxy
with `{ LocalServiceAddress: "<pod ip>", Checks: true }`. In this case,
while the checks are rewritten as expected and the agent can reach the
dynamic port, the proxy can no longer reach its backend because the
traffic is no longer on the loopback interface.
I think rewriting the checks to use `proxy.Address`, the proxy's own
address, is more correct in this case. That is the IP where the proxy
can be reached, both by other proxies and by a Consul agent running on
a different IP. The local service address should continue to use
`127.0.0.1` in most cases.
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.
This fixes issue #7318
Between versions 1.5.2 and 1.5.3, a regression has been introduced regarding health
of services. A patch #6144 had been issued for HealthChecks of nodes, but not for healthchecks
of services.
What happened when a reload was:
1. save all healthcheck statuses
2. cleanup everything
3. add new services with healthchecks
In step 3, the state of healthchecks was taken into account locally,
so at step 3, but since we cleaned up at step 2, state was lost.
This PR introduces the snap parameter, so step 3 can use information from step 1
Fixes#7231. Before an agent would always emit a warning when there is
an encrypt key in the configuration and an existing keyring stored,
which is happening on restart.
Now it only emits that warning when the encrypt key from the
configuration is not part of the keyring.
* Add CreateCSRWithSAN
* Use CreateCSRWithSAN in auto_encrypt and cache
* Copy DNSNames and IPAddresses to cert
* Verify auto_encrypt.sign returns cert with SAN
* provide configuration options for auto_encrypt dnssan and ipsan
* rename CreateCSRWithSAN to CreateCSR
* Use consts for well known tagged adress keys
* Add ipv4 and ipv6 tagged addresses for node lan and wan
* Add ipv4 and ipv6 tagged addresses for service lan and wan
* Use IPv4 and IPv6 address in DNS
* Increase number to test ignore. Consul Enterprise has more flags and since we are trying to reduce the differences between both code bases, we are increasing the number in oss. The semantics don't change, it is just a cosmetic thing.
* Introduce agent.initEnterprise for enterprise related hooks.
* Sync test with ent version.
* Fix import order.
* revert error wording.
A check may be set to become passing/critical only if a specified number of successive
checks return passing/critical in a row. Status will stay identical as before until
the threshold is reached.
This feature is available for HTTP, TCP, gRPC, Docker & Monitor checks.
Fixes: #5396
This PR adds a proxy configuration stanza called expose. These flags register
listeners in Connect sidecar proxies to allow requests to specific HTTP paths from outside of the node. This allows services to protect themselves by only
listening on the loopback interface, while still accepting traffic from non
Connect-enabled services.
Under expose there is a boolean checks flag that would automatically expose all
registered HTTP and gRPC check paths.
This stanza also accepts a paths list to expose individual paths. The primary
use case for this functionality would be to expose paths for third parties like
Prometheus or the kubelet.
Listeners for requests to exposed paths are be configured dynamically at run
time. Any time a proxy, or check can be registered, a listener can also be
created.
In this initial implementation requests to these paths are not
authenticated/encrypted.
Also:
* Finished threading replaceExistingChecks setting (from GH-4905)
through service manager.
* Respected the original configSource value that was used to register a
service or a check when restoring persisted data.
* Run several existing tests with and without central config enabled
(not exhaustive yet).
* Switch to ioutil.ReadFile for all types of agent persistence.
The embedded `Server` field on a `DNSServer` is only set inside of the
`ListenAndServe` method. If that method fails for reasons like the
address being in use and is not bindable, then the `Server` field will
not be set and the overall `Agent.Start()` will fail.
This will trigger the inner loop of `TestAgent.Start()` to invoke
`ShutdownEndpoints` which will attempt to pretty print the DNS servers
using fields on that inner `Server` field. Because it was never set,
this causes a nil pointer dereference and crashes the test.
This fixes pathological cases where the write throughput and snapshot size are both so large that more than 10k log entries are written in the time it takes to restore the snapshot from disk. In this case followers that restart can never catch up with leader replication again and enter a loop of constantly downloading a full snapshot and restoring it only to find that snapshot is already out of date and the leader has truncated its logs so a new snapshot is sent etc.
In general if you need to adjust this, you are probably abusing Consul for purposes outside its design envelope and should reconsider your usage to reduce data size and/or write volume.
* Support for maximum size for Output of checks
This PR allows users to limit the size of output produced by checks at the agent
and check level.
When set at the agent level, it will limit the output for all checks monitored
by the agent.
When set at the check level, it can override the agent max for a specific check but
only if it is lower than the agent max.
Default value is 4k, and input must be at least 1.
Daniel Nephin