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

# Setting a Container Hostname

> This article explains how to set a hostname for a Docker container and the difference between container name and hostname.

When you start a Docker container, you often assign it a name with `--name`, but this doesn’t change the hostname inside the container. Understanding the difference between a container’s name and its hostname is crucial when your application uses hostname-based logic for logging, inter-service communication, or constructing URLs.

## Container Name vs Hostname

| Option              | Scope         | Affects                                                  |
| ------------------- | ------------- | -------------------------------------------------------- |
| `--name <name>`     | Docker Engine | User-friendly container identifier at the CLI            |
| `--hostname <name>` | Container OS  | The hostname returned by `hostname` inside the container |

<Callout icon="lightbulb" color="#1CB2FE">
  The container *name* and *hostname* serve different purposes. Some applications generate logs or metrics based on the hostname, so setting it appropriately simplifies debugging and monitoring.
</Callout>

## Default Hostname Behavior

By default, Docker sets the hostname to the short version of the container’s unique ID. For example:

```bash theme={null}
docker container run -it --name webapp ubuntu
```

Inside that container, checking the hostname shows the truncated ID:

```bash theme={null}
root@3484d738:/# hostname
3484d738
```

Here, `3484d738` is the container ID—not the friendly `webapp` name you provided.

## Overriding the Hostname

To assign a meaningful hostname inside your container, use the `--hostname` (or `-h`) flag. This helps when services rely on consistent hostnames:

```bash theme={null}
docker container run -it \
  --name webapp \
  --hostname webapp \
  ubuntu
```

Now, the `hostname` command returns your custom name:

```bash theme={null}
root@webapp:/# hostname
webapp
```

Your application can now reference a predictable, human-readable hostname.

## References

* [Docker Run Reference](https://docs.docker.com/engine/reference/commandline/run/)
* [Docker Container CLI](https://docs.docker.com/engine/reference/commandline/container/)

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