I find "distributed systems" to be a huge source of imposter syndrome. Despite having worked almost exclusively with distributed applications for several years now, it is difficult to consider myself experienced. When I'm asked if I've worked with distributed systems, I don't think they are asking me if I've managed a Hadoop cluster. They are interested in building new applications using some of the primitives discussed in this post. All of these links are great, but the fact is that building and operating tools like this is hard. In addition to consensus primitives, your system may need very precise error handling, structured logging, distributed tracing, resource monitoring, schema evolution, etc. In the end, I probably pause for a second too long when answering that question, but I don't think its because of a lack of experience, quite the opposite!