Post Syndicated from Aleksandr Kotsegubov original https://blog.zabbix.com/forward-zabbix-events-to-event-driven-ansible-and-automate-your-workflows/25893/

Zabbix is highly regarded for its ability to integrate with a variety of systems right out of the box. That list of systems has recently been expanded with the addition of Event-Driven Ansible. Bringing Zabbix and Event-Driven Ansible together lets you completely automate your IT processes, with Zabbix being the source of events and Ansible serving as the executor. This article will explore in detail how to send events from Zabbix to Event-Driven Ansible.

What is Event-Driven Ansible?

Currently available in developer preview, Event-Driven Ansible is an event-based automation solution that automatically matches each new event to the conditions you specified. This eliminates routine tasks and lets you spend your time on more important issues. And because it’s a fully automated system, it doesn’t get sick, take lunch breaks, or go on vacation – by working around the clock, it can speed up important IT processes.

Sending an event from Zabbix to Event-Driven Ansible

From the Zabbix side, the implementation is a media type that uses a webhook – a tool that’s already familiar to most users. This solution allows you to take advantage of the flexibility of setting up alerts from Zabbix using actions. This media type is delivered to Zabbix out of the box, and if your installation doesn’t have it, you can import it yourself from our integrations page.

On the Event-Driven Ansible side, the webhook plugin from the ansible.eda standard collection is used. If your system doesn’t have this collection, you can get it by running the following command:

ansible-galaxy collection install ansible.eda

Let’s look at the process of sending events in more detail with the diagram below.

From the Zabbix side:

1. An event is created in Zabbix.

2. The Zabbix server checks the created event according to the conditions in the actions. If all the conditions in an action configured to send an event to Event-Driven Ansible are met, the next step (running the operations configured in the action) is executed. 

3. Sending through the “Event-Driven Ansible” media type is configured as an operation. The address specified by the service user for the “Event-Driven Ansible” media is taken as the destination.

4. The media type script processes all the information about the event, generates a JSON, and sends it to Event-Driven Ansible.
   

From the Ansible side:

1. An event sent from Zabbix arrives at the specified address and port. The webhook plugin listens on this port.

2. After receiving an event, ansible-rulebook starts checking the conditions in order to find a match between the received event and the set of rules in ansible-rulebook.

3. If the conditions for any of the rules match the incoming event, then the ansible-rulebook performs the specified action. It can be either a single command or a playbook launch.

Let’s look at the setup process from each side.

Sending events from Zabbix

Setting up sending alerts is described in detail on the Zabbix – Ansible integration page. Here are the basic steps:

1. Import the media type of the required version if it is not present in your system.

2. Create a service user. Select “Event-Driven Ansible” as the media and specify the address of your server and the port which the webhook plugin will listen in on as the destination in the format xxx.xxx.xxx.xxx:port. This article will use the value 5001 as the port. This value will still be needed to configure ansible-rulebook.

3. Configure an action to send notifications. As an operation, specify sending via “Event-Drive Ansible.” Specify the service user created in the previous step as the recipient.

Receiving events in Event-Driven Ansible

First things first – you need to have an eda-server installed. You can find detailed installation and configuration instructions here.

After installing an eda-server, you can make your first ansible-rulebook. To do this, you need to create a file with the “yml” extension. Call it zabbix-test.yml and put the following code in it:

---
- name: Zabbix test rulebook
  hosts: all
  sources:
    - ansible.eda.webhook:
        host: 0.0.0.0
        port: 5001
  rules:
    - name: debug
      condition: event.payload is defined
      action:
        debug:

Ansible-rulebook, as you may have noticed, uses the yaml format. In this case, it has 4 parameters – name, hosts, source, and rules.

Name and Host parameters

The first 2 parameters are typical for Ansible users. The name parameter contains the name of the ansible-rulebook. The hosts parameter specifies which hosts the ansible-rulebook applies to. Hosts are usually listed in the inventory file. You can learn more about the inventory file in the ansible documentation. The most interesting options are source and rules, so let’s take a closer look at them.

Source parameter

The source parameter specifies the origin of events for the ansible-rulebook. In this case, the ansible.eda.webhook plugin is specified as the event source. This means that after the start of the ansible-rulebook, the webhook plugin starts listening in on the port to receive the event. This also means that it needs 2 parameters to work:

1. Parameter “host” – a value of 0.0.0.0 used to receive events from all addresses.
2. Parameter “port” – with 5001 as the value. This plugin will accept all incoming messages received on this particular port. The value of the port parameter must match the port you specified when creating the service user in Zabbix.

Rules parameter

The rules parameter contains a set of rules with conditions for matching with an incoming event. If the condition matches the received event, then the action specified in the actions section will be performed. Since this ansible-rulebook is only for reference, it is enough to specify only one rule. For simplicity, you can use event.payload is defined as a condition. This simple condition means that the rule will check for the presence of the “event.payload” field in the incoming event. When you specify debug in the action, ansible-rulebook will show you the full text of the received event. With debug you can also understand which fields will be passed in the event and set the conditions you need.

The name, host, source parameters only affect the event source. In our case, the webhook plugin will always be the event source. Accordingly, these parameters will not change and in all the following examples they will be skipped. As an example, only the value of the rules parameter will be specified.

To start your ansible-rulebook you can use the command:

ansible-rulebook --rulebook /path/to/your/rulebook/zabbix-test.yml –verbose

The line Waiting for events in the output indicates that the ansible-rulebook has successfully loaded and is ready to receive events.

Examples 

Ansible-rulebook provides a wide variety of opportunities for handling incoming events. We will look into some of the possible conditions and scenarios for using ansible-rulebook, but please remember that a more detailed list of all supported conditions and examples can be found on the official documentation page. For a general understanding of the principles of working with ansible-rulebook, please read the documentation.

Let’s see how to build conditions for precise event filtering in more detail with a few examples.

Example #1

You need to run a playbook to change the NGINX configuration at the Berlin office when you receive an event from Zabbix. The host is in three groups:

1. Linux servers
2. Web servers
3. Berlin.

And it has 3 tags:

1. target: nginx
2. class: software
3. component: configuration.
   

You can see all these parameters in the diagram below:

On the left side you can see a host with configured monitoring. To determine whether an event belongs to a given rule, you will work with two fields – host groups and tags. These parameters will be used to determine whether the event belongs to the required server and configuration. According to the diagram, all event data is sent to the media type script to generate and send JSON. On the Ansible side, the webhook receives an event with JSON from Zabbix and passes it to the ansible-rulebook to check the conditions. If the event matches all the conditions, the ansible-rulebook starts the specified action. In this case, it’s the start of the playbook.

In accordance with the specified settings for host groups and tags, the event will contain information as in the block below. However, only two fields from the output are needed – “host_groups” and “event_tags.”

{
    ...,
    "host_groups": [
        "Berlin",
        "Linux servers",
        "Web servers"],
    "event_tags": {
        "class": ["os"],
        "component": ["configuration"],
        "target": ["nginx"]},
    ...
}

Search by host groups

First, you need to determine that the host is a web server. You can understand this by the presence of the “Web servers” group in the host in the diagram above. The second point that you can determine according to the scheme is that the host also has the group “Berlin” and therefore refers to the office in Berlin. To filter the event on the Event-Driven Ansible side, you need to build a condition by checking for the presence of two host groups in the received event – “Web servers” and “Berlin.” The “host_groups” field in the resulting JSON is a list, which means that you can use the is select construct to find an element in the list.

Search by tag value

The third condition for the search applies if this event belongs to a configuration. You can understand this by the fact that the event has a “component” tag with a value of “configuration.” However, the event_tags field in the resulting JSON is worth looking at in more detail. It is a dictionary containing tag names as keys, and because of that, you can refer to each tag separately on the Ansible side. What’s more, each tag will always contain a list of tag values, as tag names can be duplicated with different values. To search by the value of a tag, you can refer to a specific tag and use the is select construction for locating an element in the list.

To solve this example, specify the following rules block in ansible-rulebook:

  rules:
    - name: Run playbook for office in Berlin
      condition: >-
        event.payload.host_groups is select("==","Web servers") and
        event.payload.host_groups is select("==","Berlin") and
        event.payload.event_tags.component is select("==","configuration")
      action:
        run_playbook:
          name: deploy-nginx-berlin.yaml

Solution

The condition field contains 3 elements, and you can see all conditions on the right side of the diagram. In all three cases, you can use the is select construct and check if the required element is in the list.

The first two conditions check for the presence of the required host groups in the list of groups in “event.payload.host_groups.” In the diagram, you can see with a green dotted line how the first two conditions correspond to groups on the host in Zabbix. According to the condition of the example, this host must belong to both required groups, meaning that you need to set the logical operation and between the two conditions.

In the last condition, the event_tags field is a dictionary. Therefore, you can refer to the tag by specifying its name in the “event.payload.event_tags.component“ path and check for the presence of “configuration” among the tag values. In the diagram, you can see the relationship between the last condition and the tags on the host with a dotted line.

Since all three conditions must match according to the condition of the example, you once again need to put the logical operation and between them.

Action block

Let’s analyze the action block. If both conditions match, the ansible-rulebook will perform the specified action. In this case, that means the launch of the playbook using the run_playbook construct. Next, the name block contains the name of the playbook to run: deploy-nginx-berlin.yaml.

Example #2

Here is an example using the standard template Docker by Zabbix agent 2. For events triggered by “Container {#NAME}: Container has been stopped with error code”, the administrator additionally configured an action to send it to Event-Driven Ansible as well. Let’s assume that in the case of stopping the container “internal_portal” with the status “137”, its restart requires preparation, with the logic of that preparation specified in the playbook.

There are more details in the diagram above. On the left side, you can see a host with configured monitoring. The event from the example will have many parameters, but you will work with two – operational data and all tags of this event. According to the general concept, all this data will go into the media type script, which will generate JSON for sending to Event-Driven Ansible. On the Ansible side, the ansible-rulebook checks the received event for compliance with the specified conditions. If the event matches all the conditions, the ansible-rulebook starts the specified action, in this case, the start of the playbook.

In the block below you can see part of the JSON to send to Event-Driven Ansible. To solve the task, you need to be concerned only with two fields from the entire output: “event_tags” and “operation_data”:

{
    ...,
    "event_tags": {
        "class": ["software"],
        "component": ["system"],
        "container": ["/internal_portal"],
        "scope": ["availability"],
        "target": ["docker"]},
    "operation_data": "Exit code: 137",
    ...
}

Search by tag value

The first step is to determine that the event belongs to the required container. Its name is displayed in the “container” tag, so you need to add a condition to search for the name of the container “/internal_portal” in the tag. However, as discussed in the previous example, the event_tags field in the resulting JSON is a dictionary containing tag names as keys. By referring to the key to a specific tag, you can get a list of its values. Since tags can be repeated with different values, you can get all the values of this tag by key in the received JSON, and this field will always be a list. Therefore, to search by value, you can always refer to a specific tag and use the is select construction.

Search by operational data field

The second step is to check the exit code. According to the trigger settings, this information is displayed in the operational data and passed to Event-Driven Ansible in the “operation_data” field. This field is a string, and you need to check with a regular expression if this field contains the value “Exit code: 137.” On the ansible-rulebook side, the is regex construct will be used to search for a regular expression.

To solve this example, specify the following rules block in ansible-rulebook:

  rules:
    - name: Run playbook for container "internal_portal"
      condition: >-
        event.payload.event_tags.container is select("==","/internal_portal") and
        event.payload.operation_data is regex("Exit code.*137")
      action:
        run_playbook:
          name: restart_internal_portal.yaml

Solution

In the first condition, the event_tags field is a dictionary and you are referring to a specific tag, so the final path will contain the tag name, including “event.payload.event_tags.container.” Next, using the is select construct, the list of tag values is checked. This allows you to check that the required “internal_portal” container is present as the value of the tag. If you refer to the diagram, you can see the green dotted line relationship between the condition in the ansible-rulebook and the tags in the event from the Zabbix side.

In the second condition, access the event.payload.operation_data field using the is regex construct and the regular expression “Exit code.*137.” This way you check for the presence of the status “137” as a value. You can also see he link between the green dotted line of the condition on the ansible-rulebook side and the operational data of the event in Zabbix in the diagram.

Since both conditions must match, you can specify the and logical operation between the conditions.

Action block

Taking a look at the action block, if both conditions match, the ansible-rulebook will perform the specified action. In this case, it’s the launch of the playbook using the run_playbook construct. Next, the name block contains the name of the playbook to run:restart_internal_portal.yaml.

Conclusion

It’s clear that both tools (and especially their interconnected work) are great for implementing automation. Zabbix is a powerful monitoring solution, and Ansible is a great orchestration software. Both of these tools complement each other, creating an excellent tandem that takes on all routine tasks. This article has shown how to send events from Zabbix to Event-Driven Ansible and how to configure it on each side, and it has also proven that it’s not as difficult as it might initially seem. But remember – we’ve only looked at the simplest examples. The rest depends only on your imagination.

Questions

Q: How can I get the full list of fields in an event?

A: The best way is to make an ansible-rulebook with action “debug” and condition “event.payload is defined.” In this case, all events from Zabbix will be displayed. This example is described in the section “Receiving Events in Event-Driven Ansible.”

Q: Does the list of sent fields depend on the situation?

A: No. The list of fields in the sent event is always the same. If there are no objects in the event, the field will be empty. The case with tags is a good example – the tags may not be present in the event, but the “tags” field will still be sent.

Q: What events can be sent from Zabbix to Event-Drive Ansible?

A: In the current version (Zabbix 6.4)n, only trigger-based events and problems can be sent.

Q: Is it possible to use the values of received events in the ansible-playbook?

A: Yes. On the ansible-playbook side, you can get values using the ansible_eda namespace. To access the values in an event, you need to specify ansible_eda.event.

For example, to display all the details of an event, you can use:

  tasks:
    - debug:
        msg: "{{ ansible_eda.event }}"

To get the name of the container from example #2 of this article, you can use the following code:

  tasks:
    - debug:
        msg: "{{ ansible_eda.event.payload.event_tags.container }}"

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