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graph command#


The graph command generates graphical representations of a topology.

Two graphing options are available:


The HTML-based graph representation is the default graphing option. The topology will be graphed and served online using the embedded web server.

The default graph template is based on the NeXt UI framework2.


To render a topology using this default graph engine:

containerlab graph -t <path/to/topo.clab.yml>
NeXt UI#

Topology graph created with NeXt UI has some control elements that allow you to choose the color theme of the web view, scaling and panning. Besides these generic controls it is possible to enable auto-layout of the components using buttons at the top of the screen.

Layout and sorting#

The graph engine can automatically pan and sort elements in your topology based on their role. We encode the role via group property of a node.

Today we have the following sort orders available to users:

sortOrder: ['10', '9', 'superspine', '8', 'dc-gw', '7', '6', 'spine', '5', '4', 'leaf', 'border-leaf', '3', 'server', '2', '1'],
The values are sorted so that 10 is placed higher in the hierarchy than 9 and so on.

Consider the following snippet:

    ### SPINES ###
      group: spine

    ### LEAFS ###
      group: leaf

    ### CLIENTS ###
      kind: linux
      group: server

The group property set to the predefined value will automatically auto-align the elements based on their role.


When graph command is called without the --srv flag, containerlab will generate a graph description file in dot format.

The dot file can be used to view the graphical representation of the topology either by rendering the dot file into a PNG file or using online dot viewer.

Online vs offline graphing#

When HTML graph option is used, containerlab will try to build the topology graph by inspecting the running containers which are part of the lab. This essentially means, that the lab must be running. Although this method provides some additional details (like IP addresses), it is not always convenient to run a lab to see its graph.

The other option is to use the topology file solely to build the graph. This is done by adding --offline flag.

If --offline flag was not provided and no containers were found matching the lab name, containerlab will use the topo file only (as if offline mode was set).


containerlab [global-flags] graph [local-flags]



With the global --topo | -t flag a user sets the path to the topology file that will be used to get the nodes of a lab.

When the topology file flag is omitted, containerlab will try to find the matching file name by looking at the current working directory. If a single file is found, it will be used.


The --srv flag allows a user to customize the HTTP address and port for the web server. Default value is :50080.

A single path / is served, where the graph is generated based on either a default template or on the template supplied using --template.


The --template flag allows to customize the HTML based graph by supplying a user defined template that will be rendered and exposed on the address specified by --srv.


The --static-dir flag enables the embedded HTML web-server to serve static files from the specified directory. Must be used together with the --template flag.

With this flag, it is possible to link to local files (JS, CSS, fonts, etc.) from the custom HTML template.


With --dot flag provided containerlab will generate the dot file instead of serving the topology with embedded HTTP server.


# render a graph from running lab or topo file if lab is not running#
# using HTML graph option with default server address :50080
containerlab graph --topo /path/to/topo1.clab.yml

# start an http server on :3002 where topo1 graph will be rendered using a custom template my_template.html
containerlab graph --topo /path/to/topo1.clab.yml --srv ":3002" --template my_template.html

# start an http server on default port :50080 
# using a custom template that links to local files located at /path/to/static_files directory
containerlab graph --topo /path/to/topo1.clab.yml --template my_template.html --static-dir /path/to/static_files

  1. This method is prone to errors when node names contain dashes and special symbols. Use with caution, and prefer the HTML server alternative. 

  2. NeXt UI css/js files can be found at /etc/containerlab/templates/graph/nextui directory