---
title: "Dynamic Configuration via Templating"
slug: "dynamic-configuration-via-templating"
description: "Automate router-specific configurations in icom Router Management using config change templates and custom fields—ideal for scalable, location-based rollouts."
tags: ["icom Router Management"]
updated: 2025-09-02T14:53:11Z
published: 2025-09-16T07:00:05Z
canonical: "docs.insys-icom.com/dynamic-configuration-via-templating"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://docs.insys-icom.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Dynamic Configuration via Templating

**icom Router Management (iRM)** supports the creation of **reusable configuration templates** that are dynamically rendered for each router. This feature allows administrators to centrally manage configurations while adapting key values for individual devices.

> [!NOTE]
> **Note:** Using configuration templates requires an active **iRM Cloud Basic**, **iRM Server**, or **iRM Data Center** license.

**The Core Concept**

Templates contain **placeholders** that are replaced with **device-specific values** at deployment time, using iRM's **Custom Fields** and **parameters**. This approach reduces manual effort, prevents configuration errors, and ensures consistent structure across distributed router fleets — even when per-device customization is needed.

---

## Use Case: Site-Specific NTP and DNS Configuration

### Goal

An organization manages ~50 routers across various industrial sites. Each router must be configured with:

- A **unique hostname**
- A **custom domain suffix** (for internal DNS resolution)
- A **local NTP server IP** (for time synchronization with local systems)

These values vary per site but follow a standard structure. Instead of maintaining 50 separate configurations, the administrator wants to **use a single template**, populated dynamically with values from each router’s profile.

### Template Example

Below is a sample ASCII-style configuration template using iRM’s custom field placeholders:

```ini
administration.hostnames.hostname={{ .hostname }}
administration.hostnames.domainname={{ .domainname }}
administration.time.ntp_peer={{ .ntp_ip }}
```

> [!TIP]
> How it works
> 
> Each placeholder (e.g. {{ .hostname }}) will be replaced by iRM at deployment time with the value stored in the router's Custom Fields.

---

## Step-by-Step: How to Use Templates with Custom Fields

### 1. Define Custom Fields

Create the following custom fields in iRM (if not already defined):

| Field Name | Description | Example Value |
| --- | --- | --- |
| `hostname` | Desired router hostname | `mrx-berlin-001` |
| `domainname` | Desired domain name | `berlin.insys.local` |
| `ntp_ip` | IP of local NTP server | `192.168.100.10` |

To define or edit custom fields for a router:

- Navigate to the router’s detail view
- Open the **Custom Fields** section
- Enter the appropriate values

---

### 2. Create the Configuration Template

1. Go to **Inventory → Templates.**
2. Click **Add.**
3. Name the template (e.g., `Site-Specific NTP and DNS`).
4. Click **Add** to create the template. ![](https://cdn.document360.io/c690fe99-a3eb-474c-a449-c2c75e5df119/Images/Documentation/Create Template 1.png)
5. Paste the template content (see example above) and remove the placeholders (e.g. `{{ .hostname }}`). ![](https://cdn.document360.io/c690fe99-a3eb-474c-a449-c2c75e5df119/Images/Documentation/Create Template 2.png)
6. Rename the default parameter to your desired name, e.g. `hostname`
7. Use the **Type** drop-down and choose **Custom field: hostname** ![](https://cdn.document360.io/c690fe99-a3eb-474c-a449-c2c75e5df119/Images/Documentation/Create Template 3.png)
8. Next, place your cursor after the equal sign in line 1 and click on the ![application braces plus outline](https://docs.insys-icom.de/assets/icons/application-braces-plus-outline.png) **Copy parameter into template** button. This will paste the parameter in the right format at the cursor position. **![](https://cdn.document360.io/c690fe99-a3eb-474c-a449-c2c75e5df119/Images/Documentation/Create Template 4.png)**
9. Add the next parameter by clicking on **Add new parameter.**
10. Repeat steps 7 - 9 until you have all parameters added to the corresponding line of configuration. ![](https://cdn.document360.io/c690fe99-a3eb-474c-a449-c2c75e5df119/Images/Documentation/Create Template 5.png)
11. Save the template by clicking on **Save**.

---

### 3. Create an Update Job

To deploy the rendered template:

1. Use the **Select action** menu and choose **Apply to router**. ![](https://cdn.document360.io/c690fe99-a3eb-474c-a449-c2c75e5df119/Images/Documentation/Create Template 6.png)
2. Choose the target router(s) or group(s) and click on **Continue**. ![](https://cdn.document360.io/c690fe99-a3eb-474c-a449-c2c75e5df119/Images/Documentation/Create Template 7.png)
3. Review the job details. ![](https://cdn.document360.io/c690fe99-a3eb-474c-a449-c2c75e5df119/Images/Documentation/Create Template 8.png)
4. You can trigger the rollout of the template immediately by selecting **Run immediately**, or schedule it for manual execution at a later time by selecting **Start manually later**. The resulting Update Job can be viewed in **Update Management → Update Jobs**. ![](https://cdn.document360.io/c690fe99-a3eb-474c-a449-c2c75e5df119/Images/Documentation/Create Template 9.png)

> [!WARNING]
> Attention
> 
> - If a required custom field is missing on a router, the job will **fail for that device** — check the logs to identify and fix issues.
> - Templates support more complex configurations (ACLs, firewall rules, routes, etc.) using the same pattern.

For more advanced use cases or help setting up your templates, please contact our support team.