Inventory
To accommodate for smooth transition from lab deployment to subsequent automation activities, containerlab generates inventory files for different automation tools.
Ansible#
Ansible inventory is generated automatically for every lab. The inventory file can be found in the lab directory under the ansible-inventory.yml name.
Lab nodes are grouped under their kinds in the inventory so that the users can selectively choose the right group of nodes in the playbooks.
Removing ansible_host var#
If you want to use a plugin1 that doesn't play well with the ansible_host variable injected by containerlab in the inventory file, you can leverage the ansible-no-host-var label. The label can be set on per-node, kind, or default levels; if set, containerlab will not generate the ansible_host variable in the inventory for the nodes with that label.
Note that without the ansible_host variable, the connection plugin will use the inventory_hostname and resolve the name accordingly if network reachability is needed.
User-defined groups#
Users can enforce custom grouping of nodes in the inventory by adding the ansible-inventory label to the node definition:
name: custom-groups
topology:
nodes:
node1:
# <some node config data>
labels:
ansible-group: spine
node2:
# <some node config data>
labels:
ansible-group: extra_group
As a result of this configuration, the generated inventory will look like this:
children:
srl:
hosts:
clab-custom-groups-node1:
ansible_host: 172.100.100.11
clab-custom-groups-node2:
ansible_host: 172.100.100.12
extra_group:
hosts:
clab-custom-groups-node2:
ansible_host: 172.100.100.12
spine:
hosts:
clab-custom-groups-node1:
ansible_host: 172.100.100.11
Topology Data#
Every time a user runs a deploy command, containerlab automatically exports information about the topology into topology-data.json file in the lab directory. Schema of exported data is determined based on a Go template specified in --export-template parameter, or a default template /etc/containerlab/templates/export/auto.tmpl, if the parameter is not provided.
Containerlab internal data that is submitted for export via the template, has the following structure:
type TopologyExport struct {
Name string `json:"name"` // Containerlab topology name
Type string `json:"type"` // Always 'clab'
Clab *CLab `json:"clab,omitempty"` // Data parsed from a topology definitions yaml file
NodeConfigs map[string]*types.NodeConfig `json:"nodeconfigs,omitempty"` // Definitions of nodes expanded with dynamically created data
}
To get the full list of fields available for export, you can export topology data with the following template --export-template /etc/containerlab/templates/export/full.tmpl. Note, some fields exported via full.tmpl might contain sensitive information like TLS private keys. To customize export data, it is recommended to start with a copy of auto.tmpl and change it according to your needs.
Example of exported data when using default auto.tmpl template:
{
"name": "srl02",
"type": "clab",
"clab": {
"config": {
"prefix": "clab",
"mgmt": {
"network": "clab",
"bridge": "br-<...>",
"ipv4-subnet": "172.20.20.0/24",
"ipv6-subnet": "2001:172:20:20::/64",
"mtu": "1500",
"external-access": true
},
"config-path": "<full path to a directory with srl02.clab.yml>"
}
},
"nodes": {
"srl1": {
"index": "0",
"shortname": "srl1",
"longname": "clab-srl02-srl1",
"fqdn": "srl1.srl02.io",
"group": "",
"labdir": "<full path to the lab node directory>",
"kind": "srl",
"image": "ghcr.io/nokia/srlinux",
"mgmt-net": "",
"mgmt-intf": "",
"mgmt-ipv4-address": "172.20.20.3",
"mgmt-ipv4-prefix-length": 24,
"mgmt-ipv6-address": "2001:172:20:20::3",
"mgmt-ipv6-prefix-length": 64,
"mac-address": "",
"labels": {
"clab-mgmt-net-bridge": "br-<...>",
"clab-node-group": "",
"clab-node-kind": "srl",
"clab-node-lab-dir": "<full path to the lab node directory>",
"clab-node-name": "srl1",
"clab-node-type": "ixrd3",
"clab-topo-file": "<full path to the srl02.clab.yml file>",
"containerlab": "srl02"
}
},
"srl2": {
"index": "1",
"shortname": "srl2",
"longname": "clab-srl02-srl2",
"fqdn": "srl2.srl02.io",
"group": "",
"labdir": "<full path to the lab node directory>",
"kind": "srl",
"image": "ghcr.io/nokia/srlinux",
"mgmt-net": "",
"mgmt-intf": "",
"mgmt-ipv4-address": "172.20.20.2",
"mgmt-ipv4-prefix-length": 24,
"mgmt-ipv6-address": "2001:172:20:20::2",
"mgmt-ipv6-prefix-length": 64,
"mac-address": "",
"labels": {
"clab-mgmt-net-bridge": "br-<...>",
"clab-node-group": "",
"clab-node-kind": "srl",
"clab-node-lab-dir": "<full path to the lab node directory>",
"clab-node-name": "srl2",
"clab-node-type": "ixrd3",
"clab-topo-file": "<full path to the srl02.clab.yml file>",
"containerlab": "srl02"
}
}
},
"links": [
{
"a": {
"node": "srl1",
"interface": "e1-1",
"mac": "<mac address>",
"peer": "z"
},
"z": {
"node": "srl2",
"interface": "e1-1",
"mac": "<mac address>",
"peer": "a"
}
}
]
}
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For example Ansible Docker connection plugin. ↩