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Adds documentation for gRPC health checks.

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James Phillips 2018-02-02 17:53:49 -08:00
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website/source/docs/agent/checks.html.md
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@ -15,7 +15,7 @@ service. If not associated with a service, the check monitors the health of the
A check is defined in a configuration file or added at runtime over the HTTP interface. Checks
created via the HTTP interface persist with that node.
There are five different kinds of checks:
There are several different kinds of checks:
* Script + Interval - These checks depend on invoking an external application
that performs the health check, exits with an appropriate exit code, and potentially
@ -44,7 +44,7 @@ There are five different kinds of checks:
10 seconds. It is possible to configure a custom HTTP check timeout value by
specifying the `timeout` field in the check definition. The output of the
check is limited to roughly 4KB. Responses larger than this will be truncated.
HTTP checks also support SSL. By default, a valid SSL certificate is expected.
HTTP checks also support TLS. By default, a valid TLS certificate is expected.
Certificate verification can be turned off by setting the `tls_skip_verify`
field to `true` in the check definition.
@ -91,6 +91,16 @@ There are five different kinds of checks:
must be configured with [`enable_script_checks`](/docs/agent/options.html#_enable_script_checks)
set to `true` in order to enable Docker health checks.
* gRPC + Interval - These checks are intended for applications that support the standard
[gRPC health checking protocol](https://github.com/grpc/grpc/blob/master/doc/health-checking.md).
The state of the check will be updated at the given interval by probing the configured
endpoint. By default, gRPC checks will be configured with a default timeout of 10 seconds.
It is possible to configure a custom timeout value by specifying the `timeout` field in
the check definition. gRPC checks will default to not using TLS, but TLS can be enabled by
setting `grpc_use_tls` in the check definition. If TLS is enabled, then by default, a valid
TLS certificate is expected. Certificate verification can be turned off by setting the
`tls_skip_verify` field to `true` in the check definition.
## Check Definition
A script check:
@ -166,6 +176,20 @@ A Docker check:
}
```
A gRPC check:
```javascript
{
"check": {
"id": "mem-util",
"name": "Service health status",
"grpc": "127.0.0.1:12345",
"grpc_use_tls": true,
"interval": "10s"
}
}
```
Each type of definition must include a `name` and may optionally provide an
`id` and `notes` field. The `id` must be unique per _agent_ otherwise only the
last defined check with that `id` will be registered. If the `id` is not set
@ -187,8 +211,8 @@ Checks may also contain a `token` field to provide an ACL token. This token is
used for any interaction with the catalog for the check, including
[anti-entropy syncs](/docs/internals/anti-entropy.html) and deregistration.
Script, TCP, Docker and HTTP checks must include an `interval` field. This field is
parsed by Go's `time` package, and has the following
Script, TCP, HTTP, Docker, and gRPC checks must include an `interval` field. This
field is parsed by Go's `time` package, and has the following
[formatting specification](https://golang.org/pkg/time/#ParseDuration):
> A duration string is a possibly signed sequence of decimal numbers, each with
> optional fraction and a unit suffix, such as "300ms", "-1.5h" or "2h45m".
@ -206,8 +230,8 @@ any expected recoverable outage for the given service.
To configure a check, either provide it as a `-config-file` option to the
agent or place it inside the `-config-dir` of the agent. The file must
end in the ".json" extension to be loaded by Consul. Check definitions can
also be updated by sending a `SIGHUP` to the agent. Alternatively, the
end in a ".json" or ".hcl" extension to be loaded by Consul. Check definitions
can also be updated by sending a `SIGHUP` to the agent. Alternatively, the
check can be registered dynamically using the [HTTP API](/api/index.html).
## Check Scripts