Month: June 2020

BGP-Free Core

This week I have been following a discussion in NANOG about LDPv6 (there are lot of emails but it is VERY interesting) and I realized that I didnt recognize the term “BGP-Free Core”. So I searched about it. It seems it wasnt an obscure subject and funny enough I have used that design in my MPLS labs in GNS3… So what is BGP-Free core? These are the links I read:

https://blog.ipspace.net/2012/01/bgp-free-service-provider-core-in.html

And this is my favourite.

As in my basic MPLS lab, we only use BGP between PEs, and the P router only does IGP and LDP, it doesnt have to know anything about VRFs.

So for that reason, you need to increase the MTU in your links (4bytes per MPLS label) and link usage increases for the extra overhead.

So it is important to know stuff but as well how to name that stuff 😛

Indistractable

Just finished reading this book. I wanted to follow up with more info about how to improve my concentration and attention after “Deep Work”. This book is more dense. I liked the first part as there was a strong focus in the person’s psychology for distraction. We have our internal and external triggers that push us to traction (what we have to do) or distraction, and we need to identify those triggers. We need to master our internal triggers and hack back the external ones (email, app notifications, etc). We need to make time for traction and prevent distraction. And a simple timetable can give you visibility to where you are “spending” your time. Even more, you can adjust the timetable to be aligned with your values. I see connections with meditation and that works for me.

And the attention needs to start with ourselves. Then the important people around us and finally work.

I enjoyed the examples of companies like Slack to help employees to disconnect and be productive. And how important is “psychological safety” in a team..

Nowadays it is the social media the evil for our lack of attention. But in the past we have had others like television, video games, radios, books, etc. It seems Socrates complained about the written word. So there is nothing new. I liked the example of Tantalus’ curse. And now I understand the curse. He was trying to reach for things that he didnt actually need.

This is a nice screensaver:

“What we fear doing most is usually what we most need do”

And at the end there is a section for kids that I think it is very useful and original.

In summary, I have enjoyed the book and gives me more reasons to carry on my goal of better focus ( deep work / indistractable).

I hope I re-read this book at some time in the future.

Docker MTU + Docker tcpdump

I am troubleshooting an issue in a docker setup with some Arista cEOS where I can’t ping inside a VRF. First I though it was a MTU issue as when you use MPLS, there is an extra tag in the L2 frame.

…But my pings weren’t that big.

Still wanted to increase the MTU because that’s the expected thing to do in your WAN links if you run MPLS and want your users in different VRFs to be able to use the full 1500 bytes.

After some searching, It seems you can change the default value using the config file as per this link:

$ ip link show docker0
9: docker0: mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default
link/ether 02:42:be:73:8c:d3 brd ff:ff:ff:ff:ff:ff
$ cat /etc/docker/daemon.json
{
"data-root": "/home/somebody/storage/docker",
"mtu": 1600
}
$ sudo service docker restart
..
$ ip link show docker0
9: docker0: mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default
link/ether 02:42:fb:c0:cf:a2 brd ff:ff:ff:ff:ff:ff

And restart docker. But still had mtu 1500. Checking another link it seems I actually need to create a container so the bridge come up with the new value

$ docker run -d busybox top
...
9: docker0: mtu 1600 qdisc noqueue state UP mode DEFAULT group default
link/ether 02:42:fb:c0:cf:a2 brd ff:ff:ff:ff:ff:ff

Funny thing, once I started my lab again (using docker-topo) still got MTU 1500!!!

Will have to dig a bit why docker-topo doesnt take the docker mtu 1600 from the config file.

Solution: docker-topo is creating user-defined bridges, so it needs to be told that the mtu is different. The “mtu:1600” in the docker config it is only for the default bridge so when you start the busybox, it is attached to the default bridge and you see 1600.

The other thing I was curious was if I could tcpdump the networks created by docker.

Yes, you can!

# docker network ls

# ifconfig 

# tcpdump -i br-xxxx

Arancini

Sometime ago I tried these typical Italian rice bowls and like them. So I wanted to give it a go one day. The ones I tried had spinach and cheese inside. I quick search showed me videos for arancini but with meat. It looks good but wanted to try the spinach version so I went a bit free style.

These are the videos used as reference: link1 and link2

Ingredients for the rice balls

  • 1 and 1/2 cup of arborio/paella rice
  • 3 cups of boiling water
  • half onion chopped + splash of olive oil
  • pinch of sea salt
  • knob of butter
  • 1 tsp of tumeric

Process

  • Fry the onion with the oil in a deep pan until soft
  • Add the rice and mix all together for a minute
  • Add the boiling water, salt, butter and tumeric
  • Cook at middle temperature and stir often
  • Once all liquid is absorbed, spread the rice in a tray to cool down.

Ingredients for the filling

  • 500g of washed spinachs
  • half onion chopped + splash of olive oil
  • 1 garlic clove
  • splash of milk
  • 1 big tsp flour

Process

  • Fry the onion with the olive oil until soft.
  • Add the garlic and fry until golden
  • Add the spinach. They will reduce quite a lot.
  • Stir often and once the spinach are like a paste, add the milk and flour
  • Remove from heat and let it cool down

Frying the rice balls

Ingredients

  • 2 eggs
  • Breadcrumbs
  • sunflower oil (never through olive in the sink please!)
  • Cheese

Process

  • Heat up a deep pan with the sunflower oil.
  • have a plate with the breadcrumbs and another with the mixed eggs
  • For making the balls, as per videos, wet your hands, make a decent ball, and make a hole with a finger.
  • Fill the hole with the cheese and spinach.
  • Cover the ball with a bit more rice and follow the technique to shape it like an egg
  • Pass the ball by the egg, then breadcrumbs and finally into the hot oil.
  • Fry until golden

This is my result:

Veredict:

To be honest, they look as I remembered but my spinach filling wasnt as great as the ones I tried.

I think I need to use mozarella cheese and add something else to the spinach mix (salt? nutmeg?)

Next time I will try to find the Arancini recipe with spinach.

As usual, with practice, comes mastery.

Will try again.