In a previous post, I noticed that all my Kubernetes services with type=LoadBalancer were exposing some internal services as NodePorts which meant that I might be exposing internal services to the Internet at high ports. I was running Kubernetes directly on my dedicated servers and not behind a load balancer. Kubernetes expected everybody to sit behind a LB which often times required a NodePort.

The solution was to set the Service spec.allocateLoadBalancerNodePorts value to false when the service is created. This works if I can set it while I create the Service, however Helm based templates often wouldn’t allow me to set this and once it was set to true and the node port was allocated it was difficult to deallocate the NodePort.

In this post, I walk through using a Kubernetes mutating webhook to automatically set the value for all Services.

I’ve worked on several different teams over the past 8 years I’ve worked at Amazon. Each one of them had on-call in which the engineers were on-call to keep the system running 24/7 for a week. If something broke at 2am, they’d get paged to fix it.

Now, Amazon’s a big company. On-call varied quite a bit. Some teams had more ops load, others had barely any. I had my fair share of weeks with lots of tickets, but usually I sought out teams where it was more manageable. However, those engineers frequently struggled to get anywhere, playing a bit of on-call hot potato with the next on-call. Sadly, Amazon largely did not leverage SREs or dedicated support groups except for the most critical systems. I do wish they would have leveraged them.

Quick, what is this diagram trying to show?

I’ve previously explored the world of home energy monitoring systems and in the past arrived at using the Brultech GreenEye Monitor for a project in a friend’s house. It had the advantage of being local out-of-the-box and had a wide range of compact CTs that made fitting the electronics in the breaker box a lot easier, but it had one flaw that made it not suitable for my condo. It had to be mounted outside the breaker box with wires running into the box. I had no space in my condo, so I instead explored other options.

I upgraded to Apache Zeppelin v0.10.x from v0.9.x and randomly my Python Matplotlib scripts stopped rendering images. Anything that called the plot method would just return the string response of the function. Like below:

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%python
import matplotlib.pyplot as plt
plt.plot([1, 2, 3])

[<matplotlib.lines.Line2D at 0x7ff547624210>]

If this happens to you, just add the following directive after %python: