I needed to add parser settings for CoreDNS working on my Kubernetes cluster for troubleshooting but I got an error "nested repeat operator '+' and '' was replaced with '' in regular expression." I had no idea why it happened because the additional regular expression was valid. The cause of the error was my …

Fluentd is necessary software for operating Kubernetes clusters. Variables in the Fluentd’s configs are useful because they reduce redundant writing and also it will come in handy to switch environments between development and production. For example, I configure the fluentd which is running on our Kubernetes cluster …

One day, I realized that the fluentd on our Kubernetes cluster was logging a lot of "invalid date" errors like this. 1#0 dump an error event: error_class=ArgumentError error="invalid date" …