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Merge pull request #1356 from hashicorp/docker-check-docs 

Added some docs for the docker check
This commit is contained in:
Diptanu Choudhury 2015-10-28 14:57:14 -07:00
parent 402b3ea9e3 1e379f45f0
commit f38c6a8814
1 changed files with 26 additions and 2 deletions
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website/source/docs/agent/checks.html.markdown
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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 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. created via the HTTP interface persist with that node.
There are three different kinds of checks: There are four different kinds of checks:
* Script + Interval - These checks depend on invoking an external application * Script + Interval - These checks depend on invoking an external application
that performs the health check, exits with an appropriate exit code, and potentially that performs the health check, exits with an appropriate exit code, and potentially
@ -60,6 +60,16 @@ There are three different kinds of checks:
last known status of the check across restarts. Persisted check status is last known status of the check across restarts. Persisted check status is
valid through the end of the TTL from the time of the last check. valid through the end of the TTL from the time of the last check.
* Docker + Interval - These checks depend on invoking an external application which
is packaged within a Docker Container. The application is triggered within the running
container via the Docker Exec API. We expect that the Consul agent user has access
to either the Docker HTTP API or the unix socket. Consul uses ```$DOCKER_HOST``` to
determine the Docker API endpoint. The application is expected to run, perform a health
check of the service running inside the container, and exit with an appropriate exit code.
The check should be paired with an invocation interval. The shell on which the check
has to be performed is configurable which makes it possible to run containers which
have different shells on the same host.
## Check Definition ## Check Definition
A script check: A script check:
@ -116,6 +126,20 @@ A TTL check:
} }
``` ```
A Docker check:
```javascript
{
"check": {
"id": "mem-util",
"name": "Memory utilization",
"docker_container_id": "f972c95ebf0e",
"shell": "/bin/bash",
"script": "/usr/local/bin/check_mem.py",
"interval": "10s"
}
}
```
Each type of definition must include a `name` and may optionally Each type of definition must include a `name` and may optionally
provide an `id` and `notes` field. The `id` is set to the `name` if not provide an `id` and `notes` field. The `id` is set to the `name` if not
provided. It is required that all checks have a unique ID per node: if names provided. It is required that all checks have a unique ID per node: if names
@ -130,7 +154,7 @@ 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 used for any interaction with the catalog for the check, including
[anti-entropy syncs](/docs/internals/anti-entropy.html) and deregistration. [anti-entropy syncs](/docs/internals/anti-entropy.html) and deregistration.
Script, TCP and HTTP checks must include an `interval` field. This field is Script, TCP, Docker and HTTP checks must include an `interval` field. This field is
parsed by Go's `time` package, and has the following parsed by Go's `time` package, and has the following
[formatting specification](http://golang.org/pkg/time/#ParseDuration): [formatting specification](http://golang.org/pkg/time/#ParseDuration):
> A duration string is a possibly signed sequence of decimal numbers, each with > A duration string is a possibly signed sequence of decimal numbers, each with