exec command#
Description#
The exec command allows to execute a command inside the nodes (containers).
This command is similar to docker exec, but it allows to run the same command across multiple lab nodes using filters. Users can provide a path to the topology file and --label filter to narrow down the list of nodes to execute the command on.
Usage#
containerlab [global-flags] exec [local-flags]
Flags#
topology#
With the global --topo | -t flag a user can set a path to the topology file that will be used to filter the nodes targeted for execution of the command. The nodes can further be filtered with the --label flag.
Note, that with the nodes of ext-container type, the topology must not be provided.
cmd#
The command to be executed on the nodes is provided with --cmd flag. The command is provided as a string, thus it needs to be quoted to accommodate for spaces or special characters.
format#
The --format | -f flag allows selecting between plain text format output or a json variant. Consult with the examples below to see the differences between these two formatting options.
Defaults to plain output format.
label#
Using --laber it is possible to filter the nodes to execute the command on using labels attached to the nodes. The label is provided as a string in the form of key=value. The key is the label name, and the value is the label value.
Exec command should either be provided with a topology file, or labels, or both.
Recall that you can check the labels attached to the nodes with docker inspect -f '{{.Config.Labels | json}}' <container-name> command.
node-filter#
The local --node-filter flag allows a user to specify a subset of nodes from the topology to exec the command(s) on, instead of all (default). Applies to executions where the topology file is provided.
Examples#
Execute a command on all nodes of the lab#
Show ipv4 information from all the nodes of the lab defined in srl02.clab.yml with a plain text output
❯ containerlab exec -t srl02.clab.yml --cmd 'ip -4 a show dummy-mgmt0'
INFO[0000] clab-srl02-srl1: stdout:
6: dummy-mgmt0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
inet 172.20.20.3/24 brd 172.20.20.255 scope global dummy-mgmt0
valid_lft forever preferred_lft forever
INFO[0000] clab-srl02-srl2: stdout:
6: dummy-mgmt0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
inet 172.20.20.2/24 brd 172.20.20.255 scope global dummy-mgmt0
valid_lft forever preferred_lft forever
Execute a command on a node referenced by its name#
Show ipv4 information from a specific node of the lab with a plain text output
❯ containerlab exec -t srl02.clab.yml --label clab-node-name=srl2 --cmd 'ip -4 a show dummy-mgmt0'
INFO[0000] Parsing & checking topology file: srl02.yml
INFO[0000] Executed command 'ip -4 a show dummy-mgmt0' on clab-srl02-srl2. stdout:
6: dummy-mgmt0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
inet 172.20.20.5/24 brd 172.20.20.255 scope global dummy-mgmt0
valid_lft forever preferred_lft forever
Execute a command on multiple nodes referenced by a filter and no topology file#
Since containerlab injects default labels to the nodes, it is possible to leverage clab-node-kind label that is attached to all the nodes. This label contains the node kind (type) information. In this example we will execute a command on all the nodes of the lab that are of nokia_srlinux kind.
❯ sudo clab exec --label clab-node-kind=nokia_srlinux --cmd "ip -4 addr show dummy-mgmt0"
INFO[0000] Executed command "ip -4 addr show dummy-mgmt0" on the node "greeter-srl". stdout:
2: dummy-mgmt0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
inet 172.20.20.2/24 brd 172.20.20.255 scope global dummy-mgmt0
valid_lft forever preferred_lft forever
INFO[0000] Executed command "ip -4 addr show dummy-mgmt0" on the node "srl". stdout:
2: dummy-mgmt0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 1000
inet 172.20.20.3/24 brd 172.20.20.255 scope global dummy-mgmt0
valid_lft forever preferred_lft forever
Execute a CLI Command#
❯ containerlab exec -t srl02.yml --cmd 'sr_cli "show version"'
INFO[0001] clab-srl02-srl1: stdout:
----------------------------------------------------
Hostname : srl1
Chassis Type : 7250 IXR-6
Part Number : Sim Part No.
Serial Number : Sim Serial No.
System MAC Address: 02:00:6B:FF:00:00
Software Version : v20.6.3
Build Number : 145-g93496a3f8c
Architecture : x86_64
Last Booted : 2021-06-24T10:25:26.722Z
Total Memory : 24052875 kB
Free Memory : 21911906 kB
----------------------------------------------------
INFO[0003] clab-srl02-srl2: stdout:
----------------------------------------------------
Hostname : srl2
Chassis Type : 7250 IXR-6
Part Number : Sim Part No.
Serial Number : Sim Serial No.
System MAC Address: 02:D8:A9:FF:00:00
Software Version : v20.6.3
Build Number : 145-g93496a3f8c
Architecture : x86_64
Last Booted : 2021-06-24T10:25:26.904Z
Total Memory : 24052875 kB
Free Memory : 21911914 kB
----------------------------------------------------
Execute a Command with json formatted output#
{
"clab-srl02-srl1": {
"stderr": "",
"stdout": {
"basic system info": {
"Architecture": "x86_64",
"Build Number": "145-g93496a3f8c",
"Chassis Type": "7250 IXR-6",
"Free Memory": "21911367 kB",
"Hostname": "srl1",
"Last Booted": "2021-06-24T10:25:26.722Z",
"Part Number": "Sim Part No.",
"Serial Number": "Sim Serial No.",
"Software Version": "v20.6.3",
"System MAC Address": "02:00:6B:FF:00:00",
"Total Memory": "24052875 kB"
}
}
},
"clab-srl02-srl2": {
"stderr": "",
"stdout": {
"basic system info": {
"Architecture": "x86_64",
"Build Number": "145-g93496a3f8c",
"Chassis Type": "7250 IXR-6",
"Free Memory": "21911367 kB",
"Hostname": "srl2",
"Last Booted": "2021-06-24T10:25:26.904Z",
"Part Number": "Sim Part No.",
"Serial Number": "Sim Serial No.",
"Software Version": "v20.6.3",
"System MAC Address": "02:D8:A9:FF:00:00",
"Total Memory": "24052875 kB"
}
}
}
}