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How to Regulate Egress Access in Kubernetes with Istio
Usually I don’t mind to give pods unlimited egress access, ie. the pods I deployed can access the whole internet if it needs to. However when the pods take input from users it’s a whole different story. For example, running some sandbox applications such as an online Python learning environment, the workload can be abused…
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Flyway Container, MySQL and SSL/mTLS
Flyway is a handy utility to manage database schema migrations. Very similar to the schema migration mechanism in Ruby on Rails or Django, but Flyway is a standalone tool. So it’s best suited for some project which doesn’t have database schema management yet. I needed to use Flyway for a project I worked with, the…
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Bill Shock: The Real Cost of Tesla Model 3 After 1 Year
VicRoads timely reminded me that it’s time to renew my Tesla Model 3’s registration(rego), so it’s been a year already. I think it might be interesting to calculate the real cost of owning a (Tesla) EV. I also put imaginary figures of my previous diesel BMW there for an unfair comparison. Tesla Model 3 Previous…
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Some Field Test with Google Cloud Run
Recently I got a chance to migrate on-premise applications to GCP(Google Cloud Platform), and ran the apps in containers via Cloud Run. Here are some pros and cons that I think about the fully managed Cloud Run. Pros: Very easy to get started. As long as the app can run in a container, it can…
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Some Tips for CKA Exams
I’ve passed my CKA exam on my first attempt, it’s not hard because it’s the entry level certificate for Kubernetes but still a good preparation is necessary even for someone already experienced in Kubernetes. First of all, the exam is fully hands-on: every question requires a set of commands done in a terminal provided in…
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Passing Environment Variables to Terraform with RegExp
In a Terraform template, an input variable can be used to set some configuration point for a resource, such as In some scenario the input variable can get its value from an environment variable in the shell where terraform runs. It looks like This is handy where there is just a few variables. If there…
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Share Environment Variables in GNU Make
I think writing up a cheat sheet for GNU Make and environment variables before Christmas is a good idea, right? In GNU Make, by default a single line runs in its own shell. ie. We can use backslash to fake multi-line like this: With .ONESHELL directive multiple lines in one target run in a same…