consul-alerts

A simple daemon to send notifications based on Consul health checks.

Requirement

1. Consul 0.4+. Get it here.
2. Configured GOPATH.

Releases

Stable release are here.

Latest release are found here:

• darwin-amd64
• linux-386
• linux-amd64

Installation

$ go get github.com/AcalephStorage/consul-alerts
$ go install

This should install consul-alerts to $GOPATH/bin

or pull the image from docker:

$ docker pull acaleph/consul-alerts

Usage

$ consul-alerts start

or using docker:

$ docker run acaleph/consul-alerts start

By default, this runs the daemon and API at localhost:9000 and connects to the local consul agent (localhost:8500) and default datacenter (dc1). These can be overriden by the following flags:

$ consul-alerts start --alert-addr=localhost:9000 --consul-addr=localhost:8500 --consul-dc=dc1

Note: Don't change --alert-addr when using the docker container.

Once the daemon is running, it can act as a handler for consul watches. At the moment only checks and events are supported.

$ consul watch -type checks consul-alerts watch checks [--alert-addr=localhost:9000]
$ consul watch -type event consul-alerts watch event [--alert-addr=localhost:9000]

or run the watchers on the agent the daemon connects by adding the following flags during consul-alerts run:

$ consul-alerts start --watch-events --watch-checks

Configuration

All configurations are stored in consul's KV with the prefix: consul-alerts/config/. The daemon is using default values and the KV entries will only override the defaults.

Health Checks

Health checking is enabled by default. This also triggers the notification when a check has changed status for a configured duration. Health checks can be disabled by setting the kvconsul-alerts/config/checks/enabled to false.

To prevent flapping, notifications are only sent when a check status has been stable for a specific time in seconds (60 by default). this value can be changed by adding/changing the kv consul-alerts/config/checks/change-threshold to an integer greater than and divisible by 10.

eg. consul-alerts/config/checks/change-threshold = 30

Enable/Disable Specific Health Checks

There are four ways to enable/disable health check notifications: mark them by node, serviceID, checkID, or mark individually by node/serviceID/checkID. This is done by adding a KV entry in consul-alerts/config/checks/blacklist/.... Removing the entry will re-enable the check notifications.

Disable all notification by node

Add a KV entry with the key consul-alerts/config/checks/blacklist/nodes/{{ nodeName }}. This will disable notifications for the specified nodeName.

Disable all notification by service

Add a KV entry with the key consul-alerts/config/checks/blacklist/services/{{ serviceId }}. This will disable notifications for the specified serviceId.

Disable all notification by healthCheck

Add a KV entry with the key consul-alerts/config/checks/blacklist/checks/{{ checkId }}. This will disable notifications for the specified checkId.

Disable a single health check

Add a KV entry with the key consul-alerts/config/checks/blacklist/single/{{ node }}/{{ serviceId }}/{{ checkId }}. This will disable the specific health check. If the health check is not associated with a service, use the _ as the serviceId.

Events

Event handling is enabled by default. This delegates any consul event received by the agent to the list of handlers configured. To disable event handling, set consul-alerts/config/events/enabled to false.

Handlers can be configured by adding them to consul-alerts/config/events/handlers. This should be a JSON array of string. Each string should point to any executable. The event data should be read from stdin.

Notifiers

There are four builtin notifiers. Only the Log notifier is enabled by default. It is also possible to add custom notifiers similar to custom event handlers. Custom notifiers can be added in consul-alerts/config/notifiers/custom.

Logger

This logs any health check notification to a file. To disable this notifier, set consul-alerts/config/notifiers/log/enabled to false.

The log file is set to /tmp/consul-notifications.log by default. This can be changed by changing consul-alerts/config/notifiers/log/path.

Email

This emails the health notifications. To enable this, set consul-alerts/config/notifiers/email/enabled to true.

The email and smtp details needs to be configured:

prefix: consul-alerts/config/notifiers/email/

key	description
enabled	Enable the email notifier. [Default: false]
cluster-name	The name of the cluster. [Default: "Consul Alerts"]
url	The SMTP server url
port	The SMTP server port
username	The SMTP username
password	The SMTP password
sender-alias	The sender alias. [Default: "Consul Alerts"]
sender-email	The sender email
receivers	The emails of the receivers. JSON array of string
template	Path to custom email template. [Default: internal template]

The template can be any go html template. An EmailData instance will be passed to the template.

InfluxDB

This sends the notifications as series points in influxdb. Set consul-alerts/config/notifiers/influxdb/enabled to true to enabled. InfluxDB details need to be set too.

prefix: consul-alerts/config/notifiers/influxdb/

key	description
enabled	Enable the influxdb notifier. [Default: false]
host	The influxdb host. (eg. localhost:8086)
username	The influxdb username
password	The influxdb password
database	The influxdb database name
series-name	The series name for the points

Slack

Slack integration is also supported. To enable, set consul-alerts/config/notifiers/slack/enabled to true. Slack details needs to be configured.

prefix: consul-alerts/config/notifiers/slack/

key	description
enabled	Enable the Slack notifier. [Default: false]
cluster-name	The name of the cluster. [Default: "Consul Alerts"]
url	The incoming-webhook url (mandatory)
channel	The channel to post the notification (mandatory)
username	The username to appear on the post
icon-url	URL of a custom image for the notification
icon-emoji	Emoji (if not using icon-url) for the notification

In order to enable slack integration, you have to create a new Incoming WebHooks. Then use the token created by the previous action.

PagerDuty

To enable PagerDuty built-in notifier, set consul-alerts/config/notifiers/pagerduty/enabled to true. This is disabled by default. Service key and client details also needs to be configured.

prefix: consul-alerts/config/notifiers/pagerduty/

key	description
enabled	Enable the PagerDuty notifier. [Default: false]
service-key	Service key to access PagerDuty
client-name	The monitoring client name
client-url	The monitoring client url

Health Check via API

Health status can also be queried via the API. This can be used for compatibility with nagios, sensu, or other monitoring tools. To get the status of a specific check, use the following entrypoint.

http://consul-alerts:9000/v1/health?node=<node>&service=<serviceId>&check=<checkId>

This will return the output of the check and the following HTTP codes:

Status	Code
passing	200
warning	503
critical	503
unknown	404

Contribution

PRs are more than welcome. Just fork, create a feature branch, and open a PR. We love PRs. :)

TODO

This is a port from a tool we developed recently, there are still a few things missing like loading a custom configuration via command/api instead of manually editing consul's KV. Also need to set up a reminder feature. Needs better doc and some cleanup too. :)