What are Runbooks?

Runbooks are detailed guides that help IT teams perform recurring tasks and processes efficiently and consistently. They are particularly useful for incident management, providing step-by-step instructions to resolve issues. A well-structured runbook can reduce response times and minimize errors.

Contents of a Runbook

A typical runbook should include the following elements:

  1. Title: The title of the runbook should include the name of the alert or task. This helps in quickly identifying the runbook.

    Example:

    ---
title: "HostDown"
alert_group: "blackbox_alert"
alert_name: "HostDown"
---

  2. Alert Details: This section contains specific information about the alert, such as the name and the expression that triggers the alert.

    Example:

    ### Alert Details
- **Alert Name**: HostDown
- **Expression**: `sum without (cluster, job) (probe_success{nanocosmosGroup=~".+", environment=~".+"}) == 0`

  3. Description: A description of the alert, explaining what it monitors and why it is important.

    Example:

    ### Description
This alert is triggered when the sum of successful probes (`probe_success`) for all hosts in a specific group (`nanocosmosGroup`) and environment (`environment`) is equal to zero. This indicates that all hosts in this group and environment are unreachable.

  4. Possible Causes: A list of potential reasons why the alert might be triggered. This helps in quickly identifying the problem.

    Example:

    ### Possible Causes
1. Network issues affecting the reachability of the hosts.
2. All hosts in the group are down or powered off.
3. Misconfiguration of probes or monitoring tools.
4. Power supply issues or hardware failures.

  5. Troubleshooting Steps: Step-by-step instructions to diagnose and resolve the issue. This is the most important part of the runbook as it describes the specific actions to be taken.

    Example:

    ### Troubleshooting Steps

#### 1. Check Network Connectivity
Verify the network connections to the affected hosts.

```bash
# Example: Check network connectivity to a host
ping <hostname_or_ip>

    Expected Output:

    PING <hostname_or_ip> (<ip_address>) 56(84) bytes of data.
64 bytes from <hostname_or_ip>: icmp_seq=1 ttl=64 time=0.123 ms
...

    2. Verify Host Status

    Ensure that the hosts are running and reachable.

    # Example: Check the status of a host
ssh <hostname_or_ip> 'systemctl status'

    Expected Output:

    ● <service_name>.service - <Service Description>
   Loaded: loaded (/etc/systemd/system/<service_name>.service; enabled; vendor preset: enabled)
   Active: active (running) since <date>; <time> ago
...

    3. Check Probe Configuration

    Ensure that the probes are correctly configured and running.

    # Example: Check probe configuration
cat /etc/prometheus/prometheus.yml | grep -A 10 'scrape_configs:'

    Expected Output:

    scrape_configs:
  - job_name: 'probe'
    metrics_path: /probe
    params:
      module: [http_2xx]
    static_configs:
      - targets:
        - <hostname_or_ip>
...

    4. Review Logs

    Check the logs of the affected hosts and probes for errors.

    # Example: Review logs
journalctl -u <service_name> --since "1 hour ago"

    Expected Output:

    Nov 13 12:00:00 <hostname> <service_name>[1234]: Starting <service_name>...
Nov 13 12:00:01 <hostname> <service_name>[1234]: <Log message>
...

Why are Runbooks Important?

Runbooks are crucial for the smooth operation of IT systems because they:

  • Ensure Consistency: Standardized instructions ensure that all team members follow the same steps.
  • Increase Efficiency: Clear and precise instructions help resolve issues faster.
  • Reduce Errors: Detailed guides minimize human errors.
  • Support Knowledge Management: Runbooks serve as documentation and a knowledge base for new team members.