Sensu Integration

Sensu is a tool that functions as an observability pipeline which delivers monitoring as code on any cloud.

In ilert: Create a Sensu alert source

1. Go to Alert sources --> Alert sources and click on Create new alert source

   
2. Search for Sensu in the search field, click on the Sensu tile and click on Next.

   
3. Give your alert source a name, optionally assign teams and click Next.

4. Select an escalation policy by creating a new one or assigning an existing one.

   
5. Select you Alert grouping preference and click Continue setup. You may click Do not group alerts for now and change it later.

   
6. The next page show additional settings such as customer alert templates or notification prioritiy. Click on Finish setup for now.

7. On the final page, an API key and / or webhook URL will be generated that you will need later in this guide.

   

In Sensu

1. Add Sensu ilert Handler

sensuctl asset add iLert/sensu-ilert

1. Make sure that the asset was added to your Sensu backend. Run:

sensuctl asset info iLert/sensu-ilert

1. In the following command, replace <ilert_key> with your ilert API key.

Then run the updated command:

sensuctl handler create ilert \
--type pipe \
--runtime-assets iLert/sensu-ilert \
--command "sensu-ilert -t <ilert_key>"

1. Make sure that your handler was added by retrieving the complete handler definition in YAML or JSON format:

sensuctl handler info ilert --format yaml

1. Trigger an event. You can try it with the file_exists check and an ilert handler workflow in place - remove a file to cause Sensu to send a non-OK event.

You can refer to the next section for more instructions.

Triggering an event

Add system subscription to entity

1. Find your entity name:

sensuctl entity list

1. The ID in the response is the name of your entity and replace <entity_name> with the name of your entity in the sensuctl command below. Then run the command to add the system subscription to your entity:

sensuctl entity update <entity_name>

1. For Entity Class, press enter.

2. For Subscriptions, type system and press enter.

3. Confirm both sensu-backend and sensu-agent are running. You can use docker ps if you are running both from docker.

Add the file_exists check

1. Before you can add the check, you need to add the Nagios Foundation asset to your Sensu configuration:

sensuctl asset add ncr-devops-platform/nagiosfoundationCopy

1. To confirm that the asset was added to your Sensu backend, run:

sensuctl asset info ncr-devops-platform/nagiosfoundationCopy

1. The check command includes the path for the file that the check will look for on your system, /tmp/my-file.txt. For this guide, you’ll add /tmp/my-file.txt as a temporary file:

touch /tmp/my-file.txt

1. You should see === ncr-devops-platform/nagiosfoundation followed by a list of available builds for the asset. Now that you’ve added the Nagios Foundation dynamic runtime asset, you can add its file_exists check to your Sensu backend. Use sensuctl to add the check:

sensuctl check create file_exists \
--command "check_file_exists --pattern /tmp/my-file.txt" \
--subscriptions system \
--handlers ilert \
--interval 10 \
--runtime-assets ncr-devops-platform/nagiosfoundationCopy

1. To confirm that the check was added to your Sensu backend and view the check definition in YAML or JSON format,

sensuctl check info file_exists --format yaml

Trigger a file_exists check

1. Remove the file /tmp/my-file.txt:

rm /tmp/my-file.txtCopy

1. This will make sure the file is not there for Sensu to find the next time the file_exists check runs. After about 10 seconds, Sensu will detect that my-file.txt is missing and reflect that in an event. To view the event with sensuctl, run:

sensuctl event listCopy

1. The response should show that the file removal resulted in a CRITICAL (2) event:

     Entity         Check                                      Output                                   Status   Silenced             Timestamp                             UUID                  
 ────────────── ───────────── ──────────────────────────────────────────────────────────────────────── ──────── ────────── ─────────────────────────────── ────────────────────────────────────── 
  host01         file_exists   CheckFileExists CRITICAL - 0 files matched pattern /tmp/my-file.txt           2   false      2021-03-15 19:28:21 +0000 UTC   1b4266ae-7200-4728-a0n4-2f50f7a56613Copy

1. Open the Sensu web UI to see the events the file_exists check is generating. Visit http://127.0.0.1:3000, and log in as the admin user (created during initialization when you installed the Sensu backend). The failing check’s events will be listed on the Events page.

2. The Alert should be created on the Sensu Alert Source on ilert's side as well

3. To complete your workflow, restore the file that you removed so Sensu sends a resolution to ilert:

touch /tmp/my-file.txt