Containerlab Utilities

netlab clab performs these containerlab-related functions:

Building a Containerlab Distribution

The netlab clab tarball command:

  • Collects device configurations from the current lab

  • Creates a new copy of containerlab configuration file (clab.config.yml) that contains pointers to startup configurations

  • Creates a tar archive containing clab.config.yml and related device configurations.

You can use this command only after starting a containerlab-only lab topology with devices that support the startup-config containerlab parameter.

You can use the tar archive created by the netlab clab tarball to recreate the lab in a containerlab environment without installing netlab.

$ netlab clab tarball -h
usage: netlab clab tarball [-h] [-v] [-q] [--config [OUTPUT]] [--cleanup] tarball

Create a tar archive from the current clab/device configuration

positional arguments:
  tarball            Destination tarball (.tar.gz will be added if needed)

options:
  -h, --help         show this help message and exit
  -v, --verbose      Verbose logging
  -q, --quiet        Run Ansible playbook and tar with minimum output
  --config [OUTPUT]  Startup configuration directory (default: config)
  --cleanup          Clean up config directory and modified configuration file after
                     creating tarball

Building a Docker Container

netlab package includes Dockerfiles for several well-known routing daemons. You can use the netlab clab build image command to build a Docker container running the specified routing daemon.

$ netlab clab build -h
usage: netlab clab build [-h] [-l] [-t TAG] [image]

Build a routing daemon Docker container

positional arguments:
  image              Routing daemon name

options:
  -h, --help         show this help message and exit
  -l, --list         List available routing daemons
  -t TAG, --tag TAG  Specify a non-default tag for the container image

For example, use netlab clab build bird to build the netlab/bird:latest container:

To list the available Dockerfiles, use the netlab clab build –list command:

$ netlab clab build -l

The 'netlab clab build' command can be used to build the following container images

┏━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ daemon  ┃ default tag           ┃ description                                       ┃
┡━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ bird    │ netlab/bird:latest    │ BIRD Internet Routing Daemon (bird.network.cz)    │
│ bird.v3 │ netlab/bird.v3:latest │ BIRD Internet Routing Daemon (bird.network.cz) v3 │
│ dnsmasq │ netlab/dnsmasq:latest │ dnsmasq DHCP server                               │
└─────────┴───────────────────────┴───────────────────────────────────────────────────┘

For some daemons, you can build containers using different versions of that daemon. To use a non-default version of the daemon, you can:

  • Specify the default container tag with the --tag parameter, for example:

$ netlab clab build bird.v3 --tag netlab/bird:latest

  • Change the container image with the image node parameter or the defaults.daemons.daemon.clab.image default setting.

Docker Cleanup

Containerlab might refuse to bring down a lab when it encounters containers in an unexpected state, preventing netlab down from bringing down a container-based lab. Alternatively, forcing a lab shutdown with netlab down –force might result in dangling containers or Docker networks.

The easiest way to recover from these situations is to clean up the Docker containers and related objects manually. The netlab clab cleanup provides a convenient wrapper around the docker kill and docker system prune commands.

$ netlab clab cleanup -h
usage: netlab clab cleanup [-h] [-f]

Remove running containers and Docker networks

options:
  -h, --help   show this help message and exit
  -f, --force  Perform the cleanup without asking for confirmation