Containerlab – The Anti-Pattern

Posted on by Claudia de Luna
Enjoying the beach and containerlab

An intellectual is a man who says a simple thing in a difficult way; an artist is a man who says a difficult thing in a simple way.

  • Charles Bukowski - Notes of a Dirty Old Man, 1969

In a world where technology seems to be working against us and seemingly simple things require far more effort than expected and warranted, Nokia's containerlab gives us a little art with our technology.

Already making spinning up labs nearly effortless and fully automation friendly, it is no surprise that Roman Dodin's containerlab team has gone a step further.

How about spinning up a lab right from its GitHub repository?

Lets take a look.

Environment

My containerlab environment is on a VPS-3 Virtual Machine (VM) running on OVHcloud (Very cost effective as you see!)

OVHCloud VM Options
OVHCloud VM Options

Deploying Locally

I have a mock up of a data center topology in a public GitHub repository.

Normally I would clone the repository and deploy the topology. 

claudia@vps-ovh:~/containerlab$ git clone https://github.com/cldeluna/clab-via-remote.git
Cloning into 'clab-via-remote'...
remote: Enumerating objects: 10, done.
remote: Counting objects: 100% (10/10), done.
remote: Compressing objects: 100% (7/7), done.
remote: Total 10 (delta 3), reused 10 (delta 3), pack-reused 0 (from 0)
Receiving objects: 100% (10/10), 5.34 KiB | 5.34 MiB/s, done.
Resolving deltas: 100% (3/3), done.
claudia@vps-ovh:~/containerlab$ cd clab-via-remote/

Say my teammate had made updates, i would git pull and then clab deploy

claudia@vps-ovh:~/containerlab/clab-via-remote$ git pull origin main
From https://github.com/cldeluna/clab-via-remote
 * branch            main       -> FETCH_HEAD
Already up to date.

claudia@vps-ovh:~/containerlab/clab-via-remote$ clab deploy --reconfigure

Absolutly nothing wrong with this workflow and there are many use cases where you will continue to use this workflow.

In my environment, deploying the lab locally took 1 minute 9.096s.

Deploying the topology via the GitHub URL

I don't have time for all this cloning stuff!

I have created a "github-lab" directory and I run all of my "remote" topologies in there. Organize the way it makes sense for you (but please do organize!).

clab deploy -t https://github.com/cldeluna/clab-via-remote

It does not get much simpler, does it?
Notice that I didn't even give it the URL to the topology YAML file, just the repository URL!

claudia@vps-ovh:~/containerlab/github-lab$ clab deploy -t https://github.com/cldeluna/clab-via-remote
19:38:47 INFO Containerlab started version=0.70.2
19:38:47 INFO Parsing & checking topology file=sea_datacenter.clab.yml
19:38:47 INFO Creating docker network name=clab IPv4 subnet=172.20.20.0/24 IPv6 subnet=3fff:172:20:20::/64 MTU=0
19:38:47 INFO Creating lab directory path=/home/claudia/containerlab/github-lab/clab-via-remote/clab-dc1
19:38:48 INFO Creating container name=sea-dc-host4
19:38:48 INFO Creating container name=sea-dc-host2
19:38:48 INFO Creating container name=sea-dc-host5
19:38:48 INFO Creating container name=sea-dc-host1
19:38:48 INFO Creating container name=sea-dc-spine1
19:38:48 INFO Creating container name=sea-dc-spine2
19:38:48 INFO Creating container name=sea-dc-leaf4
19:38:48 INFO Creating container name=sea-dc-host3
19:38:48 INFO Creating container name=sea-dc-leaf1
19:38:48 INFO Creating container name=sea-dc-leaf2
19:38:48 INFO Creating container name=sea-dc-leaf3
19:38:48 INFO Creating container name=sea-dc-host7
19:38:48 INFO Created link: sea-dc-spine1:eth1 ▪┄┄▪ sea-dc-spine2:eth1
19:38:49 INFO Created link: sea-dc-spine1:eth6 ▪┄┄▪ sea-dc-spine2:eth6
19:38:49 INFO Creating container name=sea-dc-host6
<snip>

Now in my "github-lab" directory I have a new directory for this remote topology.

claudia@vps-ovh:~/containerlab/github-lab$ ls
clab_sea_datacenter
claudia@vps-ovh:~/containerlab$ tree github-lab/ -L 2
github-lab/
└── clab_sea_datacenter
    ├── README.md
    ├── clab-dc1
    ├── sea-dc-leaf1-config.txt
    ├── sea-dc-leaf2-config.txt
    ├── sea-dc-leaf3-config.txt
    ├── sea-dc-leaf4-config.txt
    ├── sea-dc-spine1-config.txt
    ├── sea-dc-spine2-config.txt
    └── sea_datacenter.clab.yml

2 directories, 8 files

That directory is in fact a clone. I hope this is starting to feel familiar. Containerlab is just saving us steps.

claudia@vps-ovh:~/containerlab/github-lab/clab_sea_datacenter$ git remote -v
origin  https://github.com/cldeluna/clab_sea_datacenter (fetch)
origin  https://github.com/cldeluna/clab_sea_datacenter (push)

In my environment, deploying the lab via the repo URL took 1m9.967s.

I can live with 871 milliseconds slower and that is assuming you are manually interacting with the lab. Think of the power of this in your automated workflows!

A few considerations

I executed my deploy command from the "github-lab" directory.

Keep in mind that when working locally you have a local topology file ( .clab.yml or .clab.yaml ) and your clab commands are optimized so you can use shortcuts like clab inspect and clab destroy if you are working in your topology directory.

My topology directory "github-lab" has no topology YAML file so those commands will fail.

claudia@vps-ovh:~/containerlab/github-lab$ clab destroy --cleanup

   ERROR  

  No topology files matching the pattern *.clab.yml or *.clab.yaml found.

Simply move into the newly created topology directory and you can resume your usual workflow with your abbreviated commands.

Alternatively, use the broader commands (if this is the only lab you have up)

This lets you inspect all your labs.

clab inspect --all

This lets you shut down all your labs (without prompting).

clab destroy -a -y

[!NOTE]
When using -a, the --cleanup option will not remove all the lab directories (this is documented behavior).

Conclusion

It's hard to believe it could get easier, but it has.

[!IMPORTANT]
Network Engineers, there is no excuse for not testing and modeling!

The only thing easier than containerlab (and consider that clab is a component), if you want quick fully formed topologies, is netlab from ipSpace and guess what? Netlab also supports URL deployment. Stay tuned...

My containerlab cheat sheet

I need to spin up a local topology

# cd <to the directory with your xxx.clab.yml (or xxx.clab.yaml) topology file>
clab deploy

I need to spin up a topology from a GitHub repository

 # cd <to the directory where you want to lab items created>
clab deploy --topo https://github.com/cldeluna/clab-via-remote.git

What labs are running?

# you can execute this command from anywhere 
clab inspect --all

I need to shut it all down!

clab destroy -a -y

I have a lingering topology with a status of "exit".

 docker container prune

I need to shut down a specific topology.

clab destroy -t <path and name of topology YAML file> -y --cleanup

Launching from GitHub Repo URL

claudia@vps-ovh:~$ time containerlab deploy --topo https://github.com/cldeluna/clab-via-remote.git
17:24:52 INFO Containerlab started version=0.70.1

<snip>

17:26:02 INFO Adding host entries path=/etc/hosts
17:26:02 INFO Adding SSH config for nodes path=/etc/ssh/ssh_config.d/clab-dc1.conf
🎉 A newer containerlab version (0.70.2) is available!
Release notes: https://containerlab.dev/rn/0.70/#0702
Run 'sudo clab version upgrade' or see https://containerlab.dev/install/ for installation options.
╭────────────────────────┬───────────────┬─────────┬───────────────────╮
│          Name          │   Kind/Image  │  State  │   IPv4/6 Address  │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host1  │ linux         │ running │ 172.20.20.107     │
│                        │ alpine:latest │         │ 3fff:172:20:20::2 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host2  │ linux         │ running │ 172.20.20.108     │
│                        │ alpine:latest │         │ 3fff:172:20:20::7 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host3  │ linux         │ running │ 172.20.20.109     │
│                        │ alpine:latest │         │ 3fff:172:20:20::a │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host4  │ linux         │ running │ 172.20.20.110     │
│                        │ alpine:latest │         │ 3fff:172:20:20::b │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host5  │ linux         │ running │ 172.20.20.111     │
│                        │ alpine:latest │         │ 3fff:172:20:20::5 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host6  │ linux         │ running │ 172.20.20.112     │
│                        │ alpine:latest │         │ 3fff:172:20:20::c │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host7  │ linux         │ running │ 172.20.20.113     │
│                        │ alpine:latest │         │ 3fff:172:20:20::d │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-leaf1  │ ceos          │ running │ 172.20.20.103     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::8 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-leaf2  │ ceos          │ running │ 172.20.20.104     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::e │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-leaf3  │ ceos          │ running │ 172.20.20.105     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::6 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-leaf4  │ ceos          │ running │ 172.20.20.106     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::4 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-spine1 │ ceos          │ running │ 172.20.20.101     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::9 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-spine2 │ ceos          │ running │ 172.20.20.102     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::3 │
╰────────────────────────┴───────────────┴─────────┴───────────────────╯

real    1m9.967s
user    0m0.008s
sys     0m0.004s

Launching locally from cloned repo

Clone the repository and change directory (cd) into the new directory.

claudia@vps-ovh:~/containerlab$ git clone https://github.com/cldeluna/clab_sea_datacenter.git
Cloning into 'clab_sea_datacenter'...
remote: Enumerating objects: 10, done.
remote: Counting objects: 100% (10/10), done.
remote: Compressing objects: 100% (7/7), done.
remote: Total 10 (delta 3), reused 10 (delta 3), pack-reused 0 (from 0)
Receiving objects: 100% (10/10), 5.34 KiB | 5.34 MiB/s, done.
Resolving deltas: 100% (3/3), done.
claudia@vps-ovh:~/containerlab$ cd clab_sea_datacenter/

Deploy the topology

claudia@vps-ovh:~/containerlab/clab-via-remote$ time clab deploy
17:29:03 INFO Containerlab started version=0.70.1
17:29:03 INFO Parsing & checking topology file=sea_datacenter.clab.yml

<snip>

17:30:11 INFO Adding host entries path=/etc/hosts
17:30:11 INFO Adding SSH config for nodes path=/etc/ssh/ssh_config.d/clab-dc1.conf
🎉 A newer containerlab version (0.70.2) is available!
Release notes: https://containerlab.dev/rn/0.70/#0702
Run 'sudo clab version upgrade' or see https://containerlab.dev/install/ for installation options.
╭────────────────────────┬───────────────┬─────────┬───────────────────╮
│          Name          │   Kind/Image  │  State  │   IPv4/6 Address  │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host1  │ linux         │ running │ 172.20.20.107     │
│                        │ alpine:latest │         │ 3fff:172:20:20::6 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host2  │ linux         │ running │ 172.20.20.108     │
│                        │ alpine:latest │         │ 3fff:172:20:20::a │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host3  │ linux         │ running │ 172.20.20.109     │
│                        │ alpine:latest │         │ 3fff:172:20:20::b │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host4  │ linux         │ running │ 172.20.20.110     │
│                        │ alpine:latest │         │ 3fff:172:20:20::9 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host5  │ linux         │ running │ 172.20.20.111     │
│                        │ alpine:latest │         │ 3fff:172:20:20::5 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host6  │ linux         │ running │ 172.20.20.112     │
│                        │ alpine:latest │         │ 3fff:172:20:20::7 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-host7  │ linux         │ running │ 172.20.20.113     │
│                        │ alpine:latest │         │ 3fff:172:20:20::2 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-leaf1  │ ceos          │ running │ 172.20.20.103     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::8 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-leaf2  │ ceos          │ running │ 172.20.20.104     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::e │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-leaf3  │ ceos          │ running │ 172.20.20.105     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::4 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-leaf4  │ ceos          │ running │ 172.20.20.106     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::3 │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-spine1 │ ceos          │ running │ 172.20.20.101     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::c │
├────────────────────────┼───────────────┼─────────┼───────────────────┤
│ clab-dc1-sea-dc-spine2 │ ceos          │ running │ 172.20.20.102     │
│                        │ ceos:latest   │         │ 3fff:172:20:20::d │
╰────────────────────────┴───────────────┴─────────┴───────────────────╯

real    1m9.096s
user    0m0.007s
sys     0m0.006s