This endpoint aggregates all checks related to <service id> on the agent
and return an appropriate http code + the string describing the worst
check.
This allows to cleanly expose service status to other component, hiding
complexity of multiple checks.
This is especially useful to use consul to feed a load balancer which
would delegate health checking to consul agent.
Exposing this endpoint on the agent is necessary to avoid a hit on
consul servers and avoid decreasing resiliency (this endpoint will work
even if there is no consul leader in the cluster).
This PR is almost a complete rewrite of the ACL system within Consul. It brings the features more in line with other HashiCorp products. Obviously there is quite a bit left to do here but most of it is related docs, testing and finishing the last few commands in the CLI. I will update the PR description and check off the todos as I finish them over the next few days/week.
Description
At a high level this PR is mainly to split ACL tokens from Policies and to split the concepts of Authorization from Identities. A lot of this PR is mostly just to support CRUD operations on ACLTokens and ACLPolicies. These in and of themselves are not particularly interesting. The bigger conceptual changes are in how tokens get resolved, how backwards compatibility is handled and the separation of policy from identity which could lead the way to allowing for alternative identity providers.
On the surface and with a new cluster the ACL system will look very similar to that of Nomads. Both have tokens and policies. Both have local tokens. The ACL management APIs for both are very similar. I even ripped off Nomad's ACL bootstrap resetting procedure. There are a few key differences though.
Nomad requires token and policy replication where Consul only requires policy replication with token replication being opt-in. In Consul local tokens only work with token replication being enabled though.
All policies in Nomad are globally applicable. In Consul all policies are stored and replicated globally but can be scoped to a subset of the datacenters. This allows for more granular access management.
Unlike Nomad, Consul has legacy baggage in the form of the original ACL system. The ramifications of this are:
A server running the new system must still support other clients using the legacy system.
A client running the new system must be able to use the legacy RPCs when the servers in its datacenter are running the legacy system.
The primary ACL DC's servers running in legacy mode needs to be a gate that keeps everything else in the entire multi-DC cluster running in legacy mode.
So not only does this PR implement the new ACL system but has a legacy mode built in for when the cluster isn't ready for new ACLs. Also detecting that new ACLs can be used is automatic and requires no configuration on the part of administrators. This process is detailed more in the "Transitioning from Legacy to New ACL Mode" section below.
* agent/debug: add package for debugging, host info
* api: add v1/agent/host endpoint
* agent: add v1/agent/host endpoint
* command/debug: implementation of static capture
* command/debug: tests and only configured targets
* agent/debug: add basic test for host metrics
* command/debug: add methods for dynamic data capture
* api: add debug/pprof endpoints
* command/debug: add pprof
* command/debug: timing, wg, logs to disk
* vendor: add gopsutil/disk
* command/debug: add a usage section
* website: add docs for consul debug
* agent/host: require operator:read
* api/host: improve docs and no retry timing
* command/debug: fail on extra arguments
* command/debug: fixup file permissions to 0644
* command/debug: remove server flags
* command/debug: improve clarity of usage section
* api/debug: add Trace for profiling, fix profile
* command/debug: capture profile and trace at the same time
* command/debug: add index document
* command/debug: use "clusters" in place of members
* command/debug: remove address in output
* command/debug: improve comment on metrics sleep
* command/debug: clarify usage
* agent: always register pprof handlers and protect
This will allow us to avoid a restart of a target agent
for profiling by always registering the pprof handlers.
Given this is a potentially sensitive path, it is protected
with an operator:read ACL and enable debug being
set to true on the target agent. enable_debug still requires
a restart.
If ACLs are disabled, enable_debug is sufficient.
* command/debug: use trace.out instead of .prof
More in line with golang docs.
* agent: fix comment wording
* agent: wrap table driven tests in t.run()
- A new endpoint `/v1/agent/service/:service_id` which is a generic way to look up the service for a single instance. The primary value here is that it:
- **supports hash-based blocking** and so;
- **replaces `/agent/connect/proxy/:proxy_id`** as the mechanism the built-in proxy uses to read its config.
- It's not proxy specific and so works for any service.
- It has a temporary shim to call through to the existing endpoint to preserve current managed proxy config defaulting behaviour until that is removed entirely (tested).
- The built-in proxy now uses the new endpoint exclusively for it's config
- The built-in proxy now has a `-sidecar-for` flag that allows the service ID of the _target_ service to be specified, on the condition that there is exactly one "sidecar" proxy (that is one that has `Proxy.DestinationServiceID` set) for the service registered.
- Several fixes for edge cases for SidecarService
- A fix for `Alias` checks - when running locally they didn't update their state until some external thing updated the target. If the target service has no checks registered as below, then the alias never made it past critical.
There are also a lot of small bug fixes found when testing lots of things end-to-end for the first time and some cleanup now it's integrated with real CA code.
- Includes some bug fixes for previous `api` work and `agent` that weren't tested
- Needed somewhat pervasive changes to support hash based blocking - some TODOs left in our watch toolchain that will explicitly fail on hash-based watches.
- Integration into `connect` is partially done here but still WIP
- register endpoints with supported methods
- support OPTIONS requests, indicating supported methods
- extract method validation (error 405) from individual endpoints
- on 405 where multiple methods are allowed, create a single Allow
header with comma-separated values, not multiple Allow headers.
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