Alerting

Connaisseur can send notifications on admission decisions to basically every REST endpoint that accepts JSON payloads.

Supported interfaces

Slack, Opsgenie, Keybase and Microsoft Teams have pre-configured payloads that are ready to use. Additionally, there is a template matching the Elastic Common Schema in version 1.12. However, you can use the existing payload templates as an example how to model your own custom one. It is also possible to configure multiple interfaces for receiving alerts at the same time.

Configuration options

Currently, Connaisseur supports alerting on either admittance of images, denial of images or both. These event categories can be configured independently of each other under the relevant category (i.e. admitRequest or rejectRequest):

Key	Accepted values	Default	Required	Description
alerting.clusterIdentifier	string	"not specified"	-	Cluster identifier used in alert payload to distinguish between alerts from different clusters.
alerting.<category>.receivers.[].template	opsgenie, slack, keybase, msteams, ecs-1-12-0 or custom*	-		File in helm/alert_payload_templates/ to be used as alert payload template.
alerting.<category>.receivers.[].receiverUrl	string	-		URL of alert-receiving endpoint.
alerting.<category>.receivers.[].priority	int	3	-	Priority of alert (to enable fitting Connaisseur alerts into alerts from other sources).
alerting.<category>.receivers.[].customHeaders	list[string]	-	-	Additional headers required by alert-receiving endpoint.
alerting.<category>.receivers.[].payloadFields	subyaml	-	-	Additional (yaml) key-value pairs to be appended to alert payload (as json).
alerting.<category>.receivers.[].failIfAlertSendingFails	bool	false	-	Whether to make Connaisseur deny images if the corresponding alert cannot be successfully sent.

^{*basename of the custom template file in helm/alerting_payload_templates without file extension}

Notes:

• The value for template needs to match an existing file of the pattern charts/connaisseur/alert_payload_templates/<template>.json; so if you want to use a predefined one it needs to be one of slack, keybase, opsgenie, msteams or ecs-1-12-0.
• For Opsgenie you need to configure an additional ["Authorization: GenieKey <Your-Genie-Key>"] header.
• For Elastic Common Schema 1.12.0 output, the receiverUrl has to be an HTTP/S log ingester, such as Fluentd HTTP input or Logstash HTTP input. Also customHeaders needs to be set to ["Content-Type: application/json"] for Fluentd HTTP endpoints.
• failIfAlertSendingFails only comes into play for requests that Connaisseur would have admitted as other requests would have been denied in the first place. The setting can come handy if you want to run Connaisseur in detection mode but still make sure that you get notified about what is going on in your cluster. However, this setting will significantly impact cluster interaction for everyone (i.e. block any cluster change associated to an image) if the alert sending fails permanently, e.g. accidental deletion of your Slack Webhook App, GenieKey expired...

Example

For example, if you would like to receive notifications in Keybase whenever Connaisseur admits a request to your cluster, your alerting configuration would look similar to the following snippet:

charts/connaisseur/values.yaml

alerting:
  admitRequest:
    receivers:
      - template: keybase
        receiverUrl: https://bots.keybase.io/webhookbot/<Your-Keybase-Hook-Token>

Additional notes

Creating a custom template

Along the lines of the templates that already exist you can easily define custom templates for other endpoints. The following variables can be rendered during runtime into the payload:

• alert_message
• priority
• connaisseur_pod_id
• namespace
• cluster
• timestamp
• request_id
• images

Referring to any of these variables in the templates works by Jinja2 notation (e.g. {{ timestamp }}). You can update your payload dynamically by adding payload fields in yaml representation in the payloadFields key which will be translated to JSON by Helm as is. If your REST endpoint requires particular headers, you can specify them as described above in customHeaders.

Payload fields in action

With payload fields, you can extend the same template depending on the receiver. For example, below Connaisseur's default Opsgenie template is used to send alerts that will be assigned to different users depending on whether the alert is for a successful admission or not. The payloadFields entries will be transformed to their JSON equivalents overwrite the respective entries of the template.

charts/connaisseur/values.yaml

alerting:
  admitRequest:
    receivers:
      - template: opsgenie
        receiverUrl: https://api.eu.opsgenie.com/v2/alerts
        priority: 4
        customHeaders: ["Authorization: GenieKey ABC-DEF"]
        payloadFields:
          responders:
            - username: "someone@testcompany.de"
              type: user
  rejectRequest:
    receivers:
      - template: opsgenie
        receiverUrl: https://api.eu.opsgenie.com/v2/alerts
        priority: 4
        customHeaders: ["Authorization: GenieKey ABC-DEF"]
        payloadFields:
          responders:
            - username: "cert@testcompany.de"
              type: user

The resulting payload sent to the webhook endpoint will then contain the field content:

{
    ...
    "responders": [{"type": "user", "username": "cert@testcompany.de"}],
    ...
}

Feel free to make a PR to share with the community if you add new neat templates for other third parties